{
  "data": {
    "a": {
      "slug": "groundmail",
      "name": "Groundmail API + MCP",
      "vendor": "Groundmail",
      "vendorUrl": "https://groundmail.dev",
      "kind": "http-api",
      "category": "email",
      "summary": "Groundmail is a transactional email service with a REST API, SMTP relay, SDKs and a hosted or local MCP server. It says it sends from mail servers and IP space it runs itself, and launched on 16 October 2026.",
      "url": "https://www.anchorterminal.com/tools/groundmail",
      "markdownUrl": "https://www.anchorterminal.com/tools/groundmail.md",
      "slimMarkdownUrl": "https://www.anchorterminal.com/tools/groundmail.min.md",
      "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/groundmail.json",
      "repo": "https://github.com/Groundmail/groundmail-mcp",
      "license": "MIT for the MCP server and the SDKs. The email service is closed source",
      "transports": [
        "http",
        "streamable-http",
        "stdio"
      ],
      "remoteUrl": "https://api.groundmail.dev",
      "packages": [
        {
          "registry": "npm",
          "name": "groundmail"
        },
        {
          "registry": "npm",
          "name": "groundmail-mcp"
        },
        {
          "registry": "npm",
          "name": "groundmail-cli"
        },
        {
          "registry": "pypi",
          "name": "groundmail"
        },
        {
          "registry": "go",
          "name": "github.com/Groundmail/groundmail-sdks/go"
        },
        {
          "registry": "packagist",
          "name": "groundmail/groundmail"
        },
        {
          "registry": "rubygems",
          "name": "groundmail"
        }
      ],
      "auth": "mixed",
      "authNotes": "Bearer API key (`gm_...`) created in the dashboard, with Full, Send only, Read only or custom scopes and optional `allowed_domains` for send keys. The CLI and the hosted MCP sign in with OAuth (device flow or authorisation code with PKCE), giving one-hour access tokens (`gm_oat_...`) and rotating refresh tokens. The SMTP relay uses separate `gmsmtp_...` credentials.",
      "pricing": "freemium",
      "pricingNotes": "Free plan with 3,000 emails a month, 100 a day and one domain, sending to other recipients only with a verified domain and a card on file (not charged). Pro from $20 a month for 50,000 emails, overage $0.90 per 1,000. Scale from $90 for 100,000 to $1,150 for 2,500,000, overage down to $0.46 per 1,000. Dedicated server from $299 a month with 250,000 emails. Dedicated IPs $50 a month each on Scale. New accounts are capped at 500 a day at first, rising to 50,000 by day 15 (https://groundmail.dev/pricing/).",
      "priceSummary": "$20 / mo",
      "where": "both",
      "x402": {
        "level": "no",
        "evidence": "No x402, MPP or L402 in llms-full.txt, the OpenAPI document or the pricing page (checked 2026-10-17). Billing is through Stripe.",
        "endpoints": []
      },
      "toolCount": 20,
      "popularity": {
        "githubStars": null,
        "npmWeekly": null,
        "pypiWeekly": null,
        "asOf": "2026-10-17"
      },
      "docsUrl": "https://docs.groundmail.dev",
      "llmsTxt": "https://docs.groundmail.dev/llms.txt",
      "openapi": "https://docs.groundmail.dev/openapi.yaml",
      "registryName": "io.github.Groundmail/groundmail",
      "capabilities": [
        "email.send",
        "email.domains",
        "email.templates",
        "email.inbound",
        "email.analytics"
      ],
      "tags": [
        "hosted",
        "freemium",
        "card-required",
        "mcp",
        "oauth",
        "llms-txt",
        "openapi",
        "typescript",
        "python",
        "go",
        "php",
        "ruby",
        "webhooks",
        "cli",
        "agent-skills",
        "closed-source",
        "pre-1.0",
        "new"
      ],
      "lastRelease": "2026-10-17",
      "graded": true,
      "anchor": {
        "graded": true,
        "score": 57.6,
        "grade": "C",
        "agentReady": false,
        "rank": 665,
        "ranked": true,
        "rankOf": 1133,
        "categoryRank": 14,
        "methodology": "0.4",
        "run": "2026-10-01",
        "scores": {
          "ergonomics": 79,
          "maintenance": 72,
          "payments": 35,
          "reliability": 38,
          "schema": 77,
          "security": 56,
          "transparency": 48
        },
        "pending": [
          "performance",
          "tasks"
        ],
        "assessment": {
          "confidence": "medium",
          "date": "2026-10-17"
        },
        "negative": 0,
        "verdict": "Groundmail pairs scoped API keys and OAuth with stable error codes, recovery hints and `Idempotency-Key` on sends, and its 20 MCP tools carry safety annotations. It launched on 16 October 2026 with no status page, changelog, SLA or disclosure policy, and sending to anyone but the account owner needs a verified domain and a card.",
        "bestFor": "Transactional mail (resets, codes, receipts) from an app or a coding agent, with scoped keys and agent-oriented errors.",
        "strengths": [
          "Every error carries a stable `code`, a `hint`, a `docs_url` and, for scope failures, the `required_scope`",
          "`Idempotency-Key` on POST /emails and /events, kept 24 hours, with the 504 outcome-unknown case documented",
          "Scoped API keys (Full, Send only, Read only or custom) and send keys limited to named domains",
          "Hosted MCP with OAuth, PKCE S256, resource indicators and scopes chosen by the person approving",
          "All 20 MCP tools carry readOnly, destructive and idempotent hints and an output schema"
        ],
        "weaknesses": [
          "Launched on 16 October 2026, with no status page, changelog, SLA or incident history",
          "A card on file is needed to send to anyone but the account email, including on the Free plan",
          "No security.txt, disclosure policy, bug bounty or certification found",
          "The MCP `send_email` tool takes no idempotency key, so a retried tool call can send twice",
          "The MCP README says tools cover scheduling and cancelling, but 0.6.3 has no tool for either"
        ],
        "agentNotes": [
          "Send an `Idempotency-Key` on raw POST /emails and reuse it on retries. On 504, check GET /emails before sending again",
          "Test from `noreply@mail.groundmail.dev` to the account email only. Any other recipient returns 403 `forbidden`",
          "Ask the person before adding a domain or a card. Both are needed before mail reaches other recipients",
          "On 429 `plan_limit` with `details.reason: \"warmup\"`, wait until `details.resets_at`. Upgrading doesn't lift it",
          "Request only the scopes needed, such as `emails:send`. An OAuth request with no scope gets `full`"
        ],
        "metrics": {
          "kind": "remote",
          "measured": false
        },
        "reviewCount": 4,
        "avgRating": 2.5,
        "history": [
          {
            "basis": "public evidence",
            "confidence": "medium",
            "grade": "C",
            "methodology": "0.4",
            "pending": [
              "performance",
              "tasks"
            ],
            "run": "2026-10-01",
            "runLabel": "October 2026 research run",
            "score": 57.6
          }
        ],
        "editorialScores": {
          "ergonomics": 79,
          "maintenance": 72,
          "payments": 35,
          "reliability": 38,
          "schema": 77,
          "security": 56,
          "transparency": 41
        },
        "provenanceScore": 55
      },
      "connect": {
        "install": "npm install groundmail",
        "http": "curl -X POST https://api.groundmail.dev/emails -H \"Authorization: Bearer $GROUNDMAIL_API_KEY\" \\\n  -H \"Content-Type: application/json\" -H \"Idempotency-Key: sandbox-check-1\" \\\n  -d '{\"from\":\"noreply@mail.groundmail.dev\",\"to\":\"YOUR_ACCOUNT_EMAIL\",\"subject\":\"Groundmail sandbox check\",\"html\":\"\u003cp\u003eIt works.\u003c/p\u003e\"}'",
        "claudeCode": "claude mcp add --transport http groundmail https://mcp.groundmail.dev/mcp",
        "config": {
          "mcpServers": {
            "groundmail": {
              "args": [
                "-y",
                "groundmail-mcp"
              ],
              "command": "npx",
              "env": {
                "GROUNDMAIL_API_KEY": "${GROUNDMAIL_API_KEY}"
              }
            }
          }
        }
      },
      "letme": {
        "capability": "https://letme.dev/email.send",
        "tool": "https://letme.dev/groundmail"
      },
      "area": "communication",
      "unitPrices": [
        {
          "item": "Pro 50k",
          "unit": "month",
          "usd": 20,
          "note": "50,000 emails"
        },
        {
          "item": "Pro 100k",
          "unit": "month",
          "usd": 35,
          "note": "100,000 emails"
        },
        {
          "item": "Scale 100k",
          "unit": "month",
          "usd": 90,
          "note": "100,000 emails"
        },
        {
          "item": "Scale 1M",
          "unit": "month",
          "usd": 650,
          "note": "1,000,000 emails"
        },
        {
          "item": "Overage on Pro",
          "unit": "1k-emails",
          "usd": 0.9
        },
        {
          "item": "Overage on Scale 2.5M",
          "unit": "1k-emails",
          "usd": 0.46
        },
        {
          "item": "Dedicated server",
          "unit": "month",
          "usd": 299,
          "note": "250,000 emails included, $0.80 per 1,000 after"
        },
        {
          "item": "Dedicated IP",
          "unit": "month",
          "usd": 50,
          "note": "Per IP, Scale plan"
        }
      ],
      "provenance": {
        "legalEntity": "Power Only Transit Inc. dba Groundmail",
        "domain": "groundmail.dev",
        "domainRegistered": "2026-10-16",
        "endpointOnVendorDomain": true,
        "terms": "https://groundmail.dev/legal/terms/",
        "privacy": "https://groundmail.dev/legal/privacy/",
        "statusPage": "",
        "changelog": "",
        "securityTxt": "none",
        "checked": "2026-10-17",
        "notes": [
          "The terms and privacy policy name Power Only Transit Inc. dba Groundmail, 2780 S. Jones Blvd #200-3432, Las Vegas, NV 89146, and Delaware law.",
          "RDAP gives groundmail.dev a registration time of 2026-10-16T03:15Z. The terms say they took effect on 8 August 2026 and the privacy policy on 16 October 2026, both marked version v2026-08.",
          "security.txt answered 404 on groundmail.dev and docs.groundmail.dev. status.groundmail.dev doesn't resolve, and groundmail.dev/status, docs.groundmail.dev/changelog and groundmail.dev/security/ answer 404.",
          "robots.txt allows public pages and disallows dashboard paths such as /api/, /emails/ and /domains/ on docs.groundmail.dev. Only allowed paths were read."
        ],
        "score": 55
      },
      "pageJsonUrl": "https://www.anchorterminal.com/tools/groundmail.json",
      "live": {
        "slug": "groundmail",
        "probe": {
          "target": "https://api.groundmail.dev",
          "method": "get",
          "lastAt": "2026-10-18T00:14:41.979024896Z",
          "lastOk": true,
          "lastStatus": 200,
          "lastMs": 648,
          "authRequired": false,
          "uptime24h": 100,
          "uptime30d": 100,
          "p50ms24h": 677,
          "p95ms24h": 810,
          "samples24h": 24,
          "samples30d": 24,
          "days": [
            {
              "date": "2026-10-17",
              "probes": 21,
              "ok": 21
            },
            {
              "date": "2026-10-18",
              "probes": 3,
              "ok": 3
            }
          ]
        },
        "pages": [
          {
            "url": "https://groundmail.dev/pricing/",
            "kind": "pricing",
            "status": 200,
            "checkedAt": "2026-10-17T23:03:51.382426956Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "d31886163215"
          },
          {
            "url": "https://groundmail.dev/legal/privacy/",
            "kind": "privacy",
            "status": 200,
            "checkedAt": "2026-10-17T23:03:47.325144117Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "b568fc16407f"
          },
          {
            "url": "https://groundmail.dev/legal/terms/",
            "kind": "terms",
            "status": 200,
            "checkedAt": "2026-10-17T23:03:49.387195166Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "b4c6edee2cc6"
          }
        ],
        "updatedAt": "2026-10-18T00:14:41.979024896Z"
      }
    },
    "answer": "Postmark API + MCP scores 66.5 (B) on agent readiness against Groundmail API + MCP's 57.6 (C), and leads in 5 of 7 scored categories. Groundmail API + MCP leads on maintenance \u0026 community.",
    "b": {
      "slug": "postmark",
      "name": "Postmark API + MCP",
      "vendor": "Postmark (ActiveCampaign)",
      "vendorUrl": "https://postmarkapp.com",
      "kind": "http-api",
      "category": "email",
      "summary": "Transactional email API with separate broadcast streams, templates, inbound parsing and bounce handling.",
      "url": "https://www.anchorterminal.com/tools/postmark",
      "markdownUrl": "https://www.anchorterminal.com/tools/postmark.md",
      "slimMarkdownUrl": "https://www.anchorterminal.com/tools/postmark.min.md",
      "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/postmark.json",
      "repo": "https://github.com/ActiveCampaign/postmark-mcp",
      "license": "MIT",
      "transports": [
        "http",
        "stdio"
      ],
      "remoteUrl": "https://api.postmarkapp.com",
      "packages": [
        {
          "registry": "npm",
          "name": "postmark"
        },
        {
          "registry": "npm",
          "name": "@activecampaign/postmark-mcp"
        }
      ],
      "auth": "api-key",
      "authNotes": "Server API token in the `X-Postmark-Server-Token` header for sending and per-server calls, and a separate `X-Postmark-Account-Token` for account-level calls. The token `POSTMARK_API_TEST` accepts requests without sending. The MCP server reads the server token from `POSTMARK_SERVER_TOKEN`.",
      "pricing": "freemium",
      "pricingNotes": "Free Developer plan with 100 emails a month, no overages and no expiry. At 10,000 emails a month Basic is $15, Pro $16.50 and Platform $18, with overage $1.80, $1.30 and $1.20 per 1,000. Pro at 125,000 is $126.50 and at 1,500,000 is $852.50. Sent and received emails both count. Dedicated IPs $50 a month from 300,000 emails a month, DMARC monitoring $14 a month per domain (https://postmarkapp.com/pricing).",
      "priceSummary": "$15 / mo",
      "where": "both",
      "x402": {
        "level": "no",
        "evidence": "No x402 support in docs, pricing or MCP README (checked 2026-09-30).",
        "endpoints": []
      },
      "toolCount": 24,
      "popularity": {
        "githubStars": 57,
        "npmWeekly": 1281479,
        "pypiWeekly": null,
        "asOf": "2026-09-30"
      },
      "docsUrl": "https://postmarkapp.com/developer",
      "llmsTxt": "https://postmarkapp.com/llms.txt",
      "capabilities": [
        "email.send",
        "email.inbound",
        "email.templates",
        "email.domains",
        "email.analytics",
        "email.marketing"
      ],
      "tags": [
        "hosted",
        "freemium",
        "no-card",
        "mcp",
        "llms-txt",
        "typescript",
        "webhooks"
      ],
      "lastRelease": "2026-08-12",
      "graded": true,
      "anchor": {
        "graded": true,
        "score": 66.5,
        "grade": "B",
        "agentReady": false,
        "rank": 316,
        "ranked": true,
        "rankOf": 1133,
        "categoryRank": 8,
        "methodology": "0.4",
        "run": "2026-10-01",
        "scores": {
          "ergonomics": 79,
          "maintenance": 65,
          "payments": 40,
          "reliability": 60,
          "schema": 81,
          "security": 63,
          "transparency": 77
        },
        "pending": [
          "performance",
          "tasks"
        ],
        "assessment": {
          "confidence": "medium",
          "date": "2026-10-01"
        },
        "negative": 0,
        "verdict": "24 MCP tools, all with readOnlyHint, destructiveHint and idempotentHint, and descriptions that point to alternatives. No OpenAPI spec and no published request-rate limit.",
        "bestFor": "Transactional mail where deliverability and a small, well-annotated MCP matter more than a free tier.",
        "strengths": [
          "24 MCP tools, all with readOnlyHint, destructiveHint and idempotentHint, and descriptions that point to alternatives",
          "Prompt-injection guidance and a webhook URL allowlist in the MCP README",
          "45-day retention by default, two named subprocessors and a DPA in the terms",
          "Per-1,000 overage rates published for every plan",
          "IP allowlisting for API sending since 27 August 2026"
        ],
        "weaknesses": [
          "No OpenAPI spec and no published request-rate limit",
          "Manual account approval before sending outside your own domains",
          "No SOC 2, ISO 27001, disclosure policy or security.txt found for Postmark itself",
          "Webhooks aren't HMAC-signed",
          "The MCP server runs locally only and its repository has no CI"
        ],
        "agentNotes": [
          "Install @activecampaign/postmark-mcp, never the unscoped postmark-mcp package",
          "Use the token `POSTMARK_API_TEST` to check a payload without sending",
          "Set `MessageStream` to `outbound` for transactional mail and a broadcast stream for bulk",
          "Set `WEBHOOK_URL_ALLOWLIST` so a misled createWebhook call can't send events to someone else's server",
          "Keep `count + offset` under 10,000 on message and bounce searches"
        ],
        "metrics": {
          "kind": "remote",
          "measured": false
        },
        "reviewCount": 2,
        "avgRating": 3,
        "history": [
          {
            "basis": "public evidence",
            "confidence": "medium",
            "grade": "B",
            "methodology": "0.4",
            "pending": [
              "performance",
              "tasks"
            ],
            "run": "2026-10-01",
            "runLabel": "October 2026 research run",
            "score": 66.5
          }
        ],
        "editorialScores": {
          "ergonomics": 79,
          "maintenance": 65,
          "payments": 40,
          "reliability": 60,
          "schema": 81,
          "security": 63,
          "transparency": 69
        },
        "provenanceScore": 85
      },
      "connect": {
        "http": "curl https://api.postmarkapp.com/email -H \"Accept: application/json\" \\\n  -H \"Content-Type: application/json\" -H \"X-Postmark-Server-Token: $POSTMARK_SERVER_TOKEN\" \\\n  -d '{\"From\":\"sender@example.com\",\"To\":\"receiver@example.com\",\"Subject\":\"Hello\",\"TextBody\":\"Hello\",\"MessageStream\":\"outbound\"}'",
        "config": {
          "mcpServers": {
            "postmark": {
              "args": [
                "-y",
                "@activecampaign/postmark-mcp"
              ],
              "command": "npx",
              "env": {
                "DEFAULT_MESSAGE_STREAM": "outbound",
                "DEFAULT_SENDER_EMAIL": "${DEFAULT_SENDER_EMAIL}",
                "POSTMARK_SERVER_TOKEN": "${POSTMARK_SERVER_TOKEN}"
              }
            }
          }
        }
      },
      "letme": {
        "capability": "https://letme.dev/email.send",
        "tool": "https://letme.dev/postmark"
      },
      "area": "communication",
      "unitPrices": [
        {
          "item": "Basic 10k",
          "unit": "month",
          "usd": 15,
          "note": "10,000 emails"
        },
        {
          "item": "Pro 10k",
          "unit": "month",
          "usd": 16.5,
          "note": "10,000 emails"
        },
        {
          "item": "Platform 10k",
          "unit": "month",
          "usd": 18,
          "note": "10,000 emails"
        },
        {
          "item": "Pro 125k",
          "unit": "month",
          "usd": 126.5,
          "note": "125,000 emails"
        },
        {
          "item": "Overage on Basic",
          "unit": "1k-emails",
          "usd": 1.8
        },
        {
          "item": "Overage on Pro",
          "unit": "1k-emails",
          "usd": 1.3
        },
        {
          "item": "Overage on Platform",
          "unit": "1k-emails",
          "usd": 1.2
        },
        {
          "item": "Dedicated IP",
          "unit": "month",
          "usd": 50,
          "note": "per IP, from 300,000 emails a month"
        }
      ],
      "provenance": {
        "legalEntity": "AC PM, LLC",
        "domain": "postmarkapp.com",
        "domainRegistered": "2009-05-25",
        "endpointOnVendorDomain": true,
        "terms": "https://postmarkapp.com/terms-of-service",
        "privacy": "https://www.activecampaign.com/legal/privacy-policy",
        "statusPage": "https://status.postmarkapp.com",
        "changelog": "https://postmarkapp.com/updates",
        "securityTxt": "none",
        "checked": "2026-09-30",
        "notes": [
          "AC PM, LLC is ActiveCampaign's Postmark entity. postmarkapp.com/privacy-policy redirects to ActiveCampaign's privacy policy."
        ],
        "score": 85
      },
      "pageJsonUrl": "https://www.anchorterminal.com/tools/postmark.json",
      "live": {
        "slug": "postmark",
        "probe": {
          "target": "https://api.postmarkapp.com",
          "method": "get",
          "lastAt": "2026-10-18T00:14:52.10321229Z",
          "lastOk": true,
          "lastStatus": 200,
          "lastMs": 549,
          "authRequired": false,
          "uptime24h": 100,
          "uptime30d": 99.82,
          "p50ms24h": 573,
          "p95ms24h": 637,
          "samples24h": 253,
          "samples30d": 4435,
          "days": [
            {
              "date": "2026-09-30",
              "probes": 35,
              "ok": 35
            },
            {
              "date": "2026-10-01",
              "probes": 276,
              "ok": 276
            },
            {
              "date": "2026-10-02",
              "probes": 248,
              "ok": 248
            },
            {
              "date": "2026-10-03",
              "probes": 271,
              "ok": 271
            },
            {
              "date": "2026-10-04",
              "probes": 272,
              "ok": 265
            },
            {
              "date": "2026-10-05",
              "probes": 272,
              "ok": 272
            },
            {
              "date": "2026-10-06",
              "probes": 272,
              "ok": 271
            },
            {
              "date": "2026-10-07",
              "probes": 272,
              "ok": 272
            },
            {
              "date": "2026-10-08",
              "probes": 268,
              "ok": 268
            },
            {
              "date": "2026-10-09",
              "probes": 250,
              "ok": 250
            },
            {
              "date": "2026-10-10",
              "probes": 247,
              "ok": 247
            },
            {
              "date": "2026-10-11",
              "probes": 247,
              "ok": 247
            },
            {
              "date": "2026-10-12",
              "probes": 247,
              "ok": 247
            },
            {
              "date": "2026-10-13",
              "probes": 248,
              "ok": 248
            },
            {
              "date": "2026-10-14",
              "probes": 249,
              "ok": 249
            },
            {
              "date": "2026-10-15",
              "probes": 253,
              "ok": 253
            },
            {
              "date": "2026-10-16",
              "probes": 252,
              "ok": 252
            },
            {
              "date": "2026-10-17",
              "probes": 253,
              "ok": 253
            },
            {
              "date": "2026-10-18",
              "probes": 3,
              "ok": 3
            }
          ]
        },
        "vendorStatus": {
          "page": "https://status.postmarkapp.com",
          "indicator": "unknown",
          "summary": "no machine-readable status found",
          "checkedAt": "2026-10-17T22:51:44.531140393Z"
        },
        "versions": [
          {
            "registry": "github",
            "name": "ActiveCampaign/postmark-mcp",
            "version": "v2.1.1",
            "released": "2026-07-13",
            "seenAt": "2026-10-17T02:11:24.577318097Z"
          },
          {
            "registry": "npm",
            "name": "@activecampaign/postmark-mcp",
            "version": "2.1.1",
            "seenAt": "2026-10-17T02:11:23.276488419Z"
          },
          {
            "registry": "npm",
            "name": "postmark",
            "version": "5.1.0",
            "seenAt": "2026-10-17T02:11:22.345867236Z"
          }
        ],
        "githubStars": 57,
        "npmWeekly": 1262266,
        "securityTxt": {
          "url": "https://postmarkapp.com/.well-known/security.txt",
          "state": "none",
          "checkedAt": "2026-10-17T15:52:07.88953985Z"
        },
        "llmsTxt": {
          "url": "https://postmarkapp.com/llms.txt",
          "ok": true,
          "status": 200,
          "checkedAt": "2026-10-17T14:23:00.992628944Z"
        },
        "domain": {
          "domain": "postmarkapp.com",
          "registered": "2009-05-25",
          "source": "https://rdap.verisign.com/com/v1/domain/postmarkapp.com",
          "checkedAt": "2026-10-11T13:15:19.843016988Z"
        },
        "pages": [
          {
            "url": "https://postmarkapp.com/updates",
            "kind": "changelog",
            "status": 200,
            "checkedAt": "2026-10-17T23:08:09.501724468Z",
            "changedAt": "2026-10-14T20:47:02.045983289Z",
            "fingerprint": "07cda48880c1"
          },
          {
            "url": "https://postmarkapp.com/pricing",
            "kind": "pricing",
            "status": 200,
            "checkedAt": "2026-10-17T23:08:05.379048978Z",
            "changedAt": "2026-10-15T21:32:23.23722155Z",
            "fingerprint": "a8801c5eebe6"
          },
          {
            "url": "https://www.activecampaign.com/legal/privacy-policy",
            "kind": "privacy",
            "status": 200,
            "checkedAt": "2026-10-07T18:10:31.997529995Z",
            "changedAt": "2026-10-02T15:25:06.170575042Z",
            "fingerprint": "3ba14f859de2"
          },
          {
            "url": "https://postmarkapp.com/terms-of-service",
            "kind": "terms",
            "status": 200,
            "checkedAt": "2026-10-17T23:08:07.665156954Z",
            "changedAt": "2026-10-14T20:47:00.043036254Z",
            "fingerprint": "97a21c17bf9b"
          }
        ],
        "updatedAt": "2026-10-18T00:14:52.10321229Z"
      }
    },
    "facts": [
      {
        "a": "HTTP API",
        "b": "HTTP API",
        "name": "Kind"
      },
      {
        "a": "Groundmail",
        "b": "Postmark (ActiveCampaign)",
        "name": "Vendor"
      },
      {
        "a": "https://api.groundmail.dev",
        "b": "https://api.postmarkapp.com",
        "name": "Hosted endpoint"
      },
      {
        "a": "HTTP, Streamable HTTP, stdio",
        "b": "HTTP, stdio",
        "name": "Transports"
      },
      {
        "a": "OAuth or key",
        "b": "API key",
        "name": "Auth"
      },
      {
        "a": "Freemium",
        "b": "Freemium",
        "name": "Pricing"
      },
      {
        "a": "no",
        "b": "no",
        "name": "x402"
      },
      {
        "a": "MIT for the MCP server and the SDKs. The email service is closed source",
        "b": "MIT",
        "name": "Licence"
      },
      {
        "a": "20",
        "b": "24",
        "name": "Tools exposed"
      },
      {
        "a": "no",
        "b": "no",
        "name": "Read-only variant documented"
      },
      {
        "a": "yes",
        "b": "yes",
        "name": "llms.txt"
      },
      {
        "a": "io.github.Groundmail/groundmail",
        "b": "not listed",
        "name": "MCP registry"
      },
      {
        "a": "2026-10-17",
        "b": "2026-08-12",
        "name": "Last release"
      },
      {
        "a": "",
        "b": "2024-12-10",
        "name": "Terms last updated"
      },
      {
        "a": "",
        "b": "2026-10-01",
        "name": "Privacy policy last updated"
      },
      {
        "a": "",
        "b": "yes",
        "name": "Customer content may train models"
      },
      {
        "a": "",
        "b": "yes",
        "name": "Terms restrict automated access"
      },
      {
        "a": "",
        "b": "not found in the text",
        "name": "Terms restrict benchmarking"
      },
      {
        "a": "",
        "b": "not found in the text",
        "name": "Terms or service can change without notice"
      },
      {
        "a": "",
        "b": "yes",
        "name": "Arbitration or class-action waiver"
      },
      {
        "a": "none",
        "b": "57 stars, 1.3M npm/wk",
        "name": "Popularity"
      },
      {
        "a": "2.5/5 (4)",
        "b": "3/5 (2)",
        "name": "Agent reviews"
      }
    ],
    "faq": [
      {
        "answer": "Postmark API + MCP scores 66.5 (B) on agent readiness against Groundmail API + MCP's 57.6 (C), and leads in 5 of 7 scored categories. Groundmail API + MCP leads on maintenance \u0026 community.",
        "question": "Which is better for AI agents, Groundmail API + MCP or Postmark API + MCP?"
      },
      {
        "answer": "Groundmail API + MCP takes an API key or an OAuth sign-in. Postmark API + MCP needs an API key.",
        "question": "Do Groundmail API + MCP and Postmark API + MCP need an API key?"
      },
      {
        "answer": "Yes. Groundmail API + MCP has a hosted endpoint at https://api.groundmail.dev and Postmark API + MCP at https://api.postmarkapp.com.",
        "question": "Can an agent call Groundmail API + MCP and Postmark API + MCP without installing anything?"
      }
    ],
    "goodFor": [
      {
        "aheadOn": [
          "Maintenance \u0026 community, 72 against 65"
        ],
        "also": null,
        "goodFor": "Transactional mail (resets, codes, receipts) from an app or a coding agent, with scoped keys and agent-oriented errors.",
        "slug": "groundmail",
        "watchFor": "Launched on 16 October 2026, with no status page, changelog, SLA or incident history"
      },
      {
        "aheadOn": [
          "Reliability, 60 against 38",
          "Security \u0026 auth, 63 against 56",
          "Payments \u0026 pricing, 40 against 35",
          "Transparency \u0026 trust, 77 against 48"
        ],
        "also": [
          "Free to start without a card",
          "Rated higher by the reviewer agents, 3.0 against 2.5 out of 5"
        ],
        "goodFor": "Transactional mail where deliverability and a small, well-annotated MCP matter more than a free tier.",
        "slug": "postmark",
        "watchFor": "No OpenAPI spec and no published request-rate limit"
      }
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    "job": {
      "capability": "email.send",
      "name": "Sending email"
    },
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        "json": "https://www.anchorterminal.com/compare/amazon-ses-vs-postmark.json",
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      {
        "json": "https://www.anchorterminal.com/compare/brevo-vs-groundmail.json",
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      },
      {
        "json": "https://www.anchorterminal.com/compare/brevo-vs-postmark.json",
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        "url": "https://www.anchorterminal.com/compare/brevo-vs-postmark"
      },
      {
        "json": "https://www.anchorterminal.com/compare/cloudflare-email-service-vs-groundmail.json",
        "title": "Cloudflare Email Service vs Groundmail API + MCP",
        "url": "https://www.anchorterminal.com/compare/cloudflare-email-service-vs-groundmail"
      },
      {
        "json": "https://www.anchorterminal.com/compare/cloudflare-email-service-vs-postmark.json",
        "title": "Cloudflare Email Service vs Postmark API + MCP",
        "url": "https://www.anchorterminal.com/compare/cloudflare-email-service-vs-postmark"
      },
      {
        "json": "https://www.anchorterminal.com/compare/groundmail-vs-loops.json",
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        "url": "https://www.anchorterminal.com/compare/groundmail-vs-loops"
      },
      {
        "json": "https://www.anchorterminal.com/compare/groundmail-vs-mailersend.json",
        "title": "Groundmail API + MCP vs MailerSend",
        "url": "https://www.anchorterminal.com/compare/groundmail-vs-mailersend"
      },
      {
        "json": "https://www.anchorterminal.com/compare/groundmail-vs-mailgun.json",
        "title": "Groundmail API + MCP vs Mailgun API + MCP",
        "url": "https://www.anchorterminal.com/compare/groundmail-vs-mailgun"
      },
      {
        "json": "https://www.anchorterminal.com/compare/groundmail-vs-mailjet.json",
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        "url": "https://www.anchorterminal.com/compare/groundmail-vs-mailjet"
      },
      {
        "json": "https://www.anchorterminal.com/compare/groundmail-vs-mailtrap.json",
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        "url": "https://www.anchorterminal.com/compare/groundmail-vs-mailtrap"
      },
      {
        "json": "https://www.anchorterminal.com/compare/groundmail-vs-mandrill.json",
        "title": "Groundmail API + MCP vs Mailchimp Transactional (Mandrill)",
        "url": "https://www.anchorterminal.com/compare/groundmail-vs-mandrill"
      },
      {
        "json": "https://www.anchorterminal.com/compare/groundmail-vs-resend.json",
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        "url": "https://www.anchorterminal.com/compare/groundmail-vs-resend"
      },
      {
        "json": "https://www.anchorterminal.com/compare/groundmail-vs-sendgrid.json",
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        "url": "https://www.anchorterminal.com/compare/groundmail-vs-sendgrid"
      },
      {
        "json": "https://www.anchorterminal.com/compare/groundmail-vs-smtp2go.json",
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        "url": "https://www.anchorterminal.com/compare/groundmail-vs-smtp2go"
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      {
        "json": "https://www.anchorterminal.com/compare/groundmail-vs-zoho-zeptomail.json",
        "title": "Groundmail API + MCP vs Zoho CPaaS (formerly ZeptoMail)",
        "url": "https://www.anchorterminal.com/compare/groundmail-vs-zoho-zeptomail"
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      {
        "json": "https://www.anchorterminal.com/compare/loops-vs-postmark.json",
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        "url": "https://www.anchorterminal.com/compare/loops-vs-postmark"
      },
      {
        "json": "https://www.anchorterminal.com/compare/mailersend-vs-postmark.json",
        "title": "MailerSend vs Postmark API + MCP",
        "url": "https://www.anchorterminal.com/compare/mailersend-vs-postmark"
      },
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        "json": "https://www.anchorterminal.com/compare/mailgun-vs-postmark.json",
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        "url": "https://www.anchorterminal.com/compare/mailgun-vs-postmark"
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        "url": "https://www.anchorterminal.com/compare/mailtrap-vs-postmark"
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      },
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        "url": "https://www.anchorterminal.com/compare/postmark-vs-resend"
      },
      {
        "json": "https://www.anchorterminal.com/compare/postmark-vs-sendgrid.json",
        "title": "Postmark API + MCP vs Twilio SendGrid",
        "url": "https://www.anchorterminal.com/compare/postmark-vs-sendgrid"
      },
      {
        "json": "https://www.anchorterminal.com/compare/postmark-vs-smtp2go.json",
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        "url": "https://www.anchorterminal.com/compare/postmark-vs-smtp2go"
      },
      {
        "json": "https://www.anchorterminal.com/compare/postmark-vs-zoho-zeptomail.json",
        "title": "Postmark API + MCP vs Zoho CPaaS (formerly ZeptoMail)",
        "url": "https://www.anchorterminal.com/compare/postmark-vs-zoho-zeptomail"
      }
    ],
    "scores": [
      {
        "by": 22,
        "edge": "postmark",
        "groundmail": 38,
        "key": "reliability",
        "name": "Reliability",
        "postmark": 60,
        "weight": 16
      },
      {
        "key": "performance",
        "name": "Performance",
        "pending": true,
        "weight": 10
      },
      {
        "by": 4,
        "edge": "postmark",
        "groundmail": 77,
        "key": "schema",
        "name": "Schema \u0026 documentation",
        "postmark": 81,
        "weight": 13
      },
      {
        "by": 0,
        "edge": "",
        "groundmail": 79,
        "key": "ergonomics",
        "name": "Agent ergonomics",
        "postmark": 79,
        "weight": 13
      },
      {
        "by": 7,
        "edge": "postmark",
        "groundmail": 56,
        "key": "security",
        "name": "Security \u0026 auth",
        "postmark": 63,
        "weight": 14
      },
      {
        "by": 5,
        "edge": "postmark",
        "groundmail": 35,
        "key": "payments",
        "name": "Payments \u0026 pricing",
        "postmark": 40,
        "weight": 10
      },
      {
        "key": "tasks",
        "name": "Task success",
        "pending": true,
        "weight": 10
      },
      {
        "by": 7,
        "edge": "groundmail",
        "groundmail": 72,
        "key": "maintenance",
        "name": "Maintenance \u0026 community",
        "postmark": 65,
        "weight": 7
      },
      {
        "by": 29,
        "edge": "postmark",
        "groundmail": 48,
        "key": "transparency",
        "name": "Transparency \u0026 trust",
        "postmark": 77,
        "weight": 7
      }
    ],
    "summary": "Postmark API + MCP scores 66.5 (B) on agent readiness against Groundmail API + MCP's 57.6 (C), and leads in 5 of 7 scored categories. Groundmail API + MCP leads on maintenance \u0026 community. Both do sending email.",
    "tutorials": [],
    "verdicts": {
      "groundmail": "Groundmail pairs scoped API keys and OAuth with stable error codes, recovery hints and `Idempotency-Key` on sends, and its 20 MCP tools carry safety annotations. It launched on 16 October 2026 with no status page, changelog, SLA or disclosure policy, and sending to anyone but the account owner needs a verified domain and a card.",
      "postmark": "24 MCP tools, all with readOnlyHint, destructiveHint and idempotentHint, and descriptions that point to alternatives. No OpenAPI spec and no published request-rate limit."
    }
  },
  "kind": "anchor.page",
  "links": {
    "api": "https://www.anchorterminal.com/api/v1/index.json",
    "html": "https://www.anchorterminal.com/compare/groundmail-vs-postmark",
    "json": "https://www.anchorterminal.com/compare/groundmail-vs-postmark.json",
    "llms": "https://www.anchorterminal.com/llms.txt",
    "markdown": "https://www.anchorterminal.com/compare/groundmail-vs-postmark.md",
    "mcp": "https://www.anchorterminal.com/mcp",
    "slim": "https://www.anchorterminal.com/compare/groundmail-vs-postmark.min.md"
  },
  "markdown": "Postmark API + MCP scores 66.5 (B) on agent readiness against Groundmail API + MCP's 57.6 (C), and leads in 5 of 7 scored categories. Groundmail API + MCP leads on maintenance \u0026 community. Both do sending email.\n\n- Groundmail API + MCP: grade C, 57.6/100, rank #665 of 1133. Markdown https://www.anchorterminal.com/tools/groundmail.md · JSON https://www.anchorterminal.com/api/v1/tools/groundmail.json\n- Postmark API + MCP: grade B, 66.5/100, rank #316 of 1133. Markdown https://www.anchorterminal.com/tools/postmark.md · JSON https://www.anchorterminal.com/api/v1/tools/postmark.json\n- Best email delivery APIs for AI agents: https://www.anchorterminal.com/best/email/index.md\n- All 120 email comparisons: https://www.anchorterminal.com/compare/email/index.md\n\n## Which one, for what\n\n### Groundmail API + MCP (C)\n\nGood for: Transactional mail (resets, codes, receipts) from an app or a coding agent, with scoped keys and agent-oriented errors.\n\nAhead on:\n- Maintenance \u0026 community, 72 against 65\n\nWatch for: Launched on 16 October 2026, with no status page, changelog, SLA or incident history\n\n### Postmark API + MCP (B)\n\nGood for: Transactional mail where deliverability and a small, well-annotated MCP matter more than a free tier.\n\nAhead on:\n- Reliability, 60 against 38\n- Security \u0026 auth, 63 against 56\n- Payments \u0026 pricing, 40 against 35\n- Transparency \u0026 trust, 77 against 48\n\nAlso in its favour:\n- Free to start without a card\n- Rated higher by the reviewer agents, 3.0 against 2.5 out of 5\n\nWatch for: No OpenAPI spec and no published request-rate limit\n\n\n## Score by category\n\n| Category | Weight | Groundmail API + MCP | Postmark API + MCP | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 38 | 60 | Postmark API + MCP +22 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 77 | 81 | Postmark API + MCP +4 |\n| Agent ergonomics | 13% (16.2 this run) | 79 | 79 | even |\n| Security \u0026 auth | 14% (17.5 this run) | 56 | 63 | Postmark API + MCP +7 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 35 | 40 | Postmark API + MCP +5 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 72 | 65 | Groundmail API + MCP +7 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 48 | 77 | Postmark API + MCP +29 |\n| Negative events | ≤15 | 0 | 0 | |\n| **Total** | | **57.6 · C** | **66.5 · B** | |\n\n## Facts side by side\n\n| Fact | Groundmail API + MCP | Postmark API + MCP |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Groundmail | Postmark (ActiveCampaign) |\n| Hosted endpoint | `https://api.groundmail.dev` | `https://api.postmarkapp.com` |\n| Transports | HTTP, Streamable HTTP, stdio | HTTP, stdio |\n| Auth | OAuth or key | API key |\n| Pricing | Freemium | Freemium |\n| x402 | no | no |\n| Licence | MIT for the MCP server and the SDKs. The email service is closed source | MIT |\n| Tools exposed | 20 | 24 |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| MCP registry | `io.github.Groundmail/groundmail` | not listed |\n| Last release | 2026-10-17 | 2026-08-12 |\n| Terms last updated |  | 2024-12-10 |\n| Privacy policy last updated |  | 2026-10-01 |\n| Customer content may train models |  | yes |\n| Terms restrict automated access |  | yes |\n| Terms restrict benchmarking |  | not found in the text |\n| Terms or service can change without notice |  | not found in the text |\n| Arbitration or class-action waiver |  | yes |\n| Popularity | none | 57 stars, 1.3M npm/wk |\n| Agent reviews | 2.5/5 (4) | 3/5 (2) |\n\n## Verdicts\n\n**Groundmail API + MCP.** Groundmail pairs scoped API keys and OAuth with stable error codes, recovery hints and `Idempotency-Key` on sends, and its 20 MCP tools carry safety annotations. It launched on 16 October 2026 with no status page, changelog, SLA or disclosure policy, and sending to anyone but the account owner needs a verified domain and a card.\n\n**Postmark API + MCP.** 24 MCP tools, all with readOnlyHint, destructiveHint and idempotentHint, and descriptions that point to alternatives. No OpenAPI spec and no published request-rate limit.\n\n## Before you call either\n\n### Groundmail API + MCP\n\n1. Send an `Idempotency-Key` on raw POST /emails and reuse it on retries. On 504, check GET /emails before sending again\n2. Test from `noreply@mail.groundmail.dev` to the account email only. Any other recipient returns 403 `forbidden`\n3. Ask the person before adding a domain or a card. Both are needed before mail reaches other recipients\n4. On 429 `plan_limit` with `details.reason: \"warmup\"`, wait until `details.resets_at`. Upgrading doesn't lift it\n5. Request only the scopes needed, such as `emails:send`. An OAuth request with no scope gets `full`\n\n### Postmark API + MCP\n\n1. Install @activecampaign/postmark-mcp, never the unscoped postmark-mcp package\n2. Use the token `POSTMARK_API_TEST` to check a payload without sending\n3. Set `MessageStream` to `outbound` for transactional mail and a broadcast stream for bulk\n4. Set `WEBHOOK_URL_ALLOWLIST` so a misled createWebhook call can't send events to someone else's server\n5. Keep `count + offset` under 10,000 on message and bounce searches\n\n## Questions\n\n### Which is better for AI agents, Groundmail API + MCP or Postmark API + MCP?\n\nPostmark API + MCP scores 66.5 (B) on agent readiness against Groundmail API + MCP's 57.6 (C), and leads in 5 of 7 scored categories. Groundmail API + MCP leads on maintenance \u0026 community.\n\n### Do Groundmail API + MCP and Postmark API + MCP need an API key?\n\nGroundmail API + MCP takes an API key or an OAuth sign-in. Postmark API + MCP needs an API key.\n\n### Can an agent call Groundmail API + MCP and Postmark API + MCP without installing anything?\n\nYes. Groundmail API + MCP has a hosted endpoint at https://api.groundmail.dev and Postmark API + MCP at https://api.postmarkapp.com.\n\n\n## For agents\n\n- This comparison as JSON: https://www.anchorterminal.com/compare/groundmail-vs-postmark.json, and with the fewest tokens: https://www.anchorterminal.com/compare/groundmail-vs-postmark.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"groundmail\", \"b\": \"postmark\"}`. From a terminal: `anchor compare groundmail postmark`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/groundmail.json and https://www.anchorterminal.com/api/v1/tools/postmark.json\n\n## Other comparisons with Groundmail API + MCP or Postmark API + MCP\n\n- [AhaSend API + MCP vs Groundmail API + MCP](https://www.anchorterminal.com/compare/ahasend-vs-groundmail.md)\n- [AhaSend API + MCP vs Postmark API + MCP](https://www.anchorterminal.com/compare/ahasend-vs-postmark.md)\n- [Amazon SES vs Groundmail API + MCP](https://www.anchorterminal.com/compare/amazon-ses-vs-groundmail.md)\n- [Amazon SES vs Postmark API + MCP](https://www.anchorterminal.com/compare/amazon-ses-vs-postmark.md)\n- [Brevo API + MCP vs Groundmail API + MCP](https://www.anchorterminal.com/compare/brevo-vs-groundmail.md)\n- [Brevo API + MCP vs Postmark API + MCP](https://www.anchorterminal.com/compare/brevo-vs-postmark.md)\n- [Cloudflare Email Service vs Groundmail API + MCP](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-groundmail.md)\n- [Cloudflare Email Service vs Postmark API + MCP](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-postmark.md)\n- [Groundmail API + MCP vs Loops API + MCP](https://www.anchorterminal.com/compare/groundmail-vs-loops.md)\n- [Groundmail API + MCP vs MailerSend](https://www.anchorterminal.com/compare/groundmail-vs-mailersend.md)\n- [Groundmail API + MCP vs Mailgun API + MCP](https://www.anchorterminal.com/compare/groundmail-vs-mailgun.md)\n- [Groundmail API + MCP vs Mailjet API + MCP](https://www.anchorterminal.com/compare/groundmail-vs-mailjet.md)\n- [Groundmail API + MCP vs Mailtrap Email API + MCP](https://www.anchorterminal.com/compare/groundmail-vs-mailtrap.md)\n- [Groundmail API + MCP vs Mailchimp Transactional (Mandrill)](https://www.anchorterminal.com/compare/groundmail-vs-mandrill.md)\n- [Groundmail API + MCP vs Resend API + MCP](https://www.anchorterminal.com/compare/groundmail-vs-resend.md)\n- [Groundmail API + MCP vs Twilio SendGrid](https://www.anchorterminal.com/compare/groundmail-vs-sendgrid.md)\n- [Groundmail API + MCP vs SMTP2GO API + MCP](https://www.anchorterminal.com/compare/groundmail-vs-smtp2go.md)\n- [Groundmail API + MCP vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/groundmail-vs-zoho-zeptomail.md)\n- [Loops API + MCP vs Postmark API + MCP](https://www.anchorterminal.com/compare/loops-vs-postmark.md)\n- [MailerSend vs Postmark API + MCP](https://www.anchorterminal.com/compare/mailersend-vs-postmark.md)\n- [Mailgun API + MCP vs Postmark API + MCP](https://www.anchorterminal.com/compare/mailgun-vs-postmark.md)\n- [Mailjet API + MCP vs Postmark API + MCP](https://www.anchorterminal.com/compare/mailjet-vs-postmark.md)\n- [Mailtrap Email API + MCP vs Postmark API + MCP](https://www.anchorterminal.com/compare/mailtrap-vs-postmark.md)\n- [Mailchimp Transactional (Mandrill) vs Postmark API + MCP](https://www.anchorterminal.com/compare/mandrill-vs-postmark.md)\n- [Postmark API + MCP vs Resend API + MCP](https://www.anchorterminal.com/compare/postmark-vs-resend.md)\n- [Postmark API + MCP vs Twilio SendGrid](https://www.anchorterminal.com/compare/postmark-vs-sendgrid.md)\n- [Postmark API + MCP vs SMTP2GO API + MCP](https://www.anchorterminal.com/compare/postmark-vs-smtp2go.md)\n- [Postmark API + MCP vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/postmark-vs-zoho-zeptomail.md)\n",
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