{
  "data": {
    "a": {
      "slug": "mailjet",
      "name": "Mailjet API + MCP",
      "vendor": "Mailjet (Sinch)",
      "vendorUrl": "https://www.mailjet.com",
      "kind": "http-api",
      "category": "email",
      "summary": "Sinch-owned email API with Send API v3.1, SMTP relay, a Parse API for inbound mail, templates and a marketing editor.",
      "url": "https://www.anchorterminal.com/tools/mailjet",
      "markdownUrl": "https://www.anchorterminal.com/tools/mailjet.md",
      "slimMarkdownUrl": "https://www.anchorterminal.com/tools/mailjet.min.md",
      "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/mailjet.json",
      "repo": "https://github.com/mailjet/mailjet-apiv3-nodejs",
      "license": "MIT",
      "transports": [
        "http",
        "stdio"
      ],
      "remoteUrl": "https://api.mailjet.com/v3.1",
      "packages": [
        {
          "registry": "npm",
          "name": "node-mailjet"
        },
        {
          "registry": "npm",
          "name": "@mailjet/mailjet-mcp-server"
        },
        {
          "registry": "pypi",
          "name": "mailjet-rest"
        }
      ],
      "auth": "api-key",
      "authNotes": "HTTP Basic auth with the public API key as user and the secret key as password. The MCP server takes both as MAILJET_API_KEY in `key:secret` form, and MAILJET_API_REGION=eu switches to EU servers.",
      "pricing": "freemium",
      "pricingNotes": "Free 6,000 emails a month capped at 200 a day, no card. Starter $9 a month (8,000 emails), Essential $19 (15,000), Premium $29 (15,000), with prices rising by volume and 10 per cent off yearly. Emails over the plan are billed per extra 1,000 at a rate published in the help centre, which we couldn't read. Enterprise on quote (https://www.mailjet.com/pricing/).",
      "priceSummary": "$9 / mo",
      "where": "both",
      "x402": {
        "level": "no",
        "evidence": "No x402 or stablecoin payment path in docs or pricing (checked 2026-09-30).",
        "endpoints": []
      },
      "toolCount": 117,
      "popularity": {
        "githubStars": 255,
        "npmWeekly": 177150,
        "pypiWeekly": 244633,
        "asOf": "2026-09-30"
      },
      "docsUrl": "https://dev.mailjet.com",
      "llmsTxt": "https://dev.mailjet.com/llms.txt",
      "openapi": "https://dev.mailjet.com/_bundle/openapi/openapi-mailjet.yaml",
      "capabilities": [
        "email.send",
        "email.inbound",
        "email.templates",
        "email.domains",
        "email.analytics",
        "email.marketing"
      ],
      "tags": [
        "hosted",
        "freemium",
        "no-card",
        "mcp",
        "llms-txt",
        "openapi",
        "typescript",
        "python",
        "webhooks"
      ],
      "lastRelease": "2026-09-14",
      "graded": true,
      "anchor": {
        "graded": true,
        "score": 59.5,
        "grade": "C",
        "agentReady": false,
        "rank": 264,
        "ranked": true,
        "rankOf": 452,
        "categoryRank": 7,
        "methodology": "0.3",
        "run": "2026-10-01",
        "scores": {
          "ergonomics": 53,
          "maintenance": 79,
          "payments": 30,
          "reliability": 62,
          "schema": 76,
          "security": 52,
          "transparency": 73
        },
        "pending": [
          "performance",
          "tasks"
        ],
        "assessment": {
          "confidence": "medium",
          "date": "2026-10-01"
        },
        "negative": 0,
        "verdict": "SandboxMode on Send API v3.1 validates a payload without delivering it. The MCP server registers 117 GET-only tools and can't send.",
        "strengths": [
          "SandboxMode on Send API v3.1 validates a payload without delivering it",
          "Data stored on Google Cloud in Frankfurt and Saint-Ghislain",
          "Parse API routes inbound mail to a webhook",
          "OpenAPI files, llms.txt and Markdown pages",
          "Free plan of 6,000 emails a month with no card"
        ],
        "weaknesses": [
          "The MCP server registers 117 GET-only tools and can't send",
          "No numeric rate limits published",
          "Price per extra 1,000 emails isn't on the pricing page",
          "No bug bounty, disclosure policy or security.txt found",
          "npm has MCP 1.1.0 while the git tags stop at a beta"
        ],
        "agentNotes": [
          "Set `SandboxMode` to true on the first sends to check payloads without delivering",
          "Send with POST /v3.1/send and a `Messages` array, many messages per call",
          "Use the MCP for statistics and contact lookups only, since it can't send",
          "Pass `MAILJET_API_KEY` as `key:secret`. The server checks it at startup and exits if it's wrong",
          "On 429, wait and retry. Non-transactional endpoints have much lower limits than send"
        ],
        "metrics": {
          "kind": "remote",
          "measured": false
        },
        "reviewCount": 2,
        "avgRating": 2.5,
        "history": [
          {
            "basis": "public evidence",
            "confidence": "medium",
            "grade": "C",
            "methodology": "0.3",
            "pending": [
              "performance",
              "tasks"
            ],
            "run": "2026-10-01",
            "runLabel": "October 2026 research run",
            "score": 59.5
          }
        ],
        "editorialScores": {
          "ergonomics": 53,
          "maintenance": 79,
          "payments": 30,
          "reliability": 62,
          "schema": 76,
          "security": 52,
          "transparency": 55
        },
        "provenanceScore": 90
      },
      "connect": {
        "http": "curl -X POST https://api.mailjet.com/v3.1/send --user \"$MJ_APIKEY_PUBLIC:$MJ_APIKEY_PRIVATE\" \\\n  -H \"Content-Type: application/json\" -d '{\"Messages\":[{\"From\":{\"Email\":\"you@example.com\"},\"To\":[{\"Email\":\"them@example.com\"}],\"Subject\":\"Hello\",\"TextPart\":\"Hello from Mailjet\"}]}'",
        "claudeCode": "claude mcp add mailjet -e MAILJET_API_KEY=\"$MJ_APIKEY_PUBLIC:$MJ_APIKEY_PRIVATE\" -- npx -y @mailjet/mailjet-mcp-server",
        "config": {
          "mcpServers": {
            "mailjet": {
              "args": [
                "-y",
                "@mailjet/mailjet-mcp-server"
              ],
              "command": "npx",
              "env": {
                "MAILJET_API_KEY": "${MJ_APIKEY_PUBLIC}:${MJ_APIKEY_PRIVATE}"
              }
            }
          }
        }
      },
      "letme": {
        "capability": "https://letme.dev/email.send",
        "tool": "https://letme.dev/mailjet"
      },
      "area": "communication",
      "unitPrices": [
        {
          "item": "Starter",
          "unit": "month",
          "usd": 9,
          "note": "8,000 emails a month"
        },
        {
          "item": "Essential",
          "unit": "month",
          "usd": 19,
          "note": "15,000 emails a month"
        },
        {
          "item": "Premium",
          "unit": "month",
          "usd": 29,
          "note": "15,000 emails a month, automations and dedicated IP from 100k"
        }
      ],
      "provenance": {
        "legalEntity": "Mailjet SAS",
        "domain": "mailjet.com",
        "domainRegistered": "2006-11-08",
        "endpointOnVendorDomain": true,
        "terms": "https://www.mailjet.com/legal/terms/",
        "privacy": "https://www.mailjet.com/legal/privacy-policy/",
        "statusPage": "https://mailjet.statuspage.io/",
        "changelog": "https://www.mailjet.com/releases/",
        "securityTxt": "none",
        "checked": "2026-09-30",
        "notes": [
          "Mailjet is a Sinch brand. The terms list Mailjet SAS, Mailjet GmbH and Mailgun Technologies, Inc. as contracting entities depending on the customer."
        ],
        "score": 90
      },
      "pageJsonUrl": "https://www.anchorterminal.com/tools/mailjet.json",
      "live": {
        "slug": "mailjet",
        "probe": {
          "target": "https://api.mailjet.com/v3.1",
          "method": "get",
          "lastAt": "2026-10-05T00:57:23.456210136Z",
          "lastOk": true,
          "lastStatus": 404,
          "lastMs": 43,
          "authRequired": false,
          "uptime24h": 100,
          "uptime30d": 100,
          "p50ms24h": 48,
          "p95ms24h": 139,
          "samples24h": 272,
          "samples30d": 1113,
          "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": 272
            },
            {
              "date": "2026-10-05",
              "probes": 11,
              "ok": 11
            }
          ]
        },
        "vendorStatus": {
          "page": "https://mailjet.statuspage.io",
          "indicator": "none",
          "summary": "All Systems Operational",
          "checkedAt": "2026-10-05T00:53:56.181185609Z"
        },
        "versions": [
          {
            "registry": "github",
            "name": "mailjet/mailjet-apiv3-nodejs",
            "version": "v7.1.0",
            "released": "2026-08-19",
            "seenAt": "2026-10-04T16:32:25.488655721Z"
          },
          {
            "registry": "npm",
            "name": "@mailjet/mailjet-mcp-server",
            "version": "1.1.0",
            "seenAt": "2026-10-04T16:32:23.608016042Z"
          },
          {
            "registry": "npm",
            "name": "node-mailjet",
            "version": "6.0.11",
            "seenAt": "2026-10-04T16:32:23.044348854Z"
          },
          {
            "registry": "pypi",
            "name": "mailjet-rest",
            "version": "1.9.0",
            "released": "2026-09-14",
            "seenAt": "2026-10-04T16:32:25.305171581Z"
          }
        ],
        "githubStars": 255,
        "npmWeekly": 187414,
        "pypiWeekly": 238046,
        "securityTxt": {
          "url": "https://mailjet.com/.well-known/security.txt",
          "state": "none",
          "checkedAt": "2026-10-04T15:15:42.087773455Z"
        },
        "llmsTxt": {
          "url": "https://dev.mailjet.com/llms.txt",
          "ok": true,
          "status": 200,
          "checkedAt": "2026-10-04T15:17:57.772258273Z"
        },
        "domain": {
          "domain": "mailjet.com",
          "registered": "2006-11-08",
          "source": "https://rdap.verisign.com/com/v1/domain/mailjet.com",
          "checkedAt": "2026-10-04T13:08:17.150993109Z"
        },
        "pages": [
          {
            "url": "https://www.mailjet.com/releases/",
            "kind": "changelog",
            "status": 200,
            "checkedAt": "2026-10-04T15:51:18.13806271Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "67d03918114f"
          },
          {
            "url": "https://www.mailjet.com/pricing/",
            "kind": "pricing",
            "status": 304,
            "checkedAt": "2026-10-04T15:51:16.153493813Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "ca0a13159f03"
          },
          {
            "url": "https://www.mailjet.com/legal/privacy-policy/",
            "kind": "privacy",
            "status": 304,
            "checkedAt": "2026-10-04T15:51:12.111220481Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "43ec4206a3d6"
          },
          {
            "url": "https://www.mailjet.com/legal/terms/",
            "kind": "terms",
            "status": 304,
            "checkedAt": "2026-10-04T15:51:14.142260312Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "bd8f1e18634f"
          }
        ],
        "updatedAt": "2026-10-05T00:57:23.456210136Z"
      }
    },
    "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": 66.7,
        "grade": "B",
        "agentReady": false,
        "rank": 158,
        "ranked": true,
        "rankOf": 452,
        "categoryRank": 3,
        "methodology": "0.3",
        "run": "2026-10-01",
        "scores": {
          "ergonomics": 79,
          "maintenance": 65,
          "payments": 40,
          "reliability": 60,
          "schema": 81,
          "security": 63,
          "transparency": 80
        },
        "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.",
        "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": "0.3",
            "pending": [
              "performance",
              "tasks"
            ],
            "run": "2026-10-01",
            "runLabel": "October 2026 research run",
            "score": 66.7
          }
        ],
        "editorialScores": {
          "ergonomics": 79,
          "maintenance": 65,
          "payments": 40,
          "reliability": 60,
          "schema": 81,
          "security": 63,
          "transparency": 69
        },
        "provenanceScore": 90
      },
      "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": 90
      },
      "pageJsonUrl": "https://www.anchorterminal.com/tools/postmark.json",
      "live": {
        "slug": "postmark",
        "probe": {
          "target": "https://api.postmarkapp.com",
          "method": "get",
          "lastAt": "2026-10-05T00:57:26.416087567Z",
          "lastOk": true,
          "lastStatus": 200,
          "lastMs": 650,
          "authRequired": false,
          "uptime24h": 97.43,
          "uptime30d": 99.37,
          "p50ms24h": 591,
          "p95ms24h": 4196,
          "samples24h": 272,
          "samples30d": 1113,
          "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": 11,
              "ok": 11
            }
          ]
        },
        "vendorStatus": {
          "page": "https://status.postmarkapp.com",
          "indicator": "unknown",
          "summary": "no machine-readable status found",
          "checkedAt": "2026-10-04T21:40:24.509628112Z"
        },
        "versions": [
          {
            "registry": "github",
            "name": "ActiveCampaign/postmark-mcp",
            "version": "v2.1.1",
            "released": "2026-07-13",
            "seenAt": "2026-10-04T16:37:29.067665935Z"
          },
          {
            "registry": "npm",
            "name": "@activecampaign/postmark-mcp",
            "version": "2.1.1",
            "seenAt": "2026-10-04T16:37:27.105943117Z"
          },
          {
            "registry": "npm",
            "name": "postmark",
            "version": "5.1.0",
            "seenAt": "2026-10-04T16:37:26.847244966Z"
          }
        ],
        "githubStars": 57,
        "npmWeekly": 1390363,
        "securityTxt": {
          "url": "https://postmarkapp.com/.well-known/security.txt",
          "state": "none",
          "checkedAt": "2026-10-04T15:15:57.369008774Z"
        },
        "llmsTxt": {
          "url": "https://postmarkapp.com/llms.txt",
          "ok": true,
          "status": 200,
          "checkedAt": "2026-10-04T15:18:08.635997833Z"
        },
        "domain": {
          "domain": "postmarkapp.com",
          "registered": "2009-05-25",
          "source": "https://rdap.verisign.com/com/v1/domain/postmarkapp.com",
          "checkedAt": "2026-10-04T13:05:40.955344563Z"
        },
        "pages": [
          {
            "url": "https://postmarkapp.com/updates",
            "kind": "changelog",
            "status": 200,
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  "markdown": "Postmark API + MCP has a score of 66.7 (B) against Mailjet API + MCP's 59.5 (C). Both do email send. The largest gap is agent ergonomics, 26 points.\n\n- Mailjet API + MCP: grade C, 59.5/100, rank #264 of 452. Markdown https://www.anchorterminal.com/tools/mailjet.md · JSON https://www.anchorterminal.com/api/v1/tools/mailjet.json\n- Postmark API + MCP: grade B, 66.7/100, rank #158 of 452. Markdown https://www.anchorterminal.com/tools/postmark.md · JSON https://www.anchorterminal.com/api/v1/tools/postmark.json\n\n## Which one, for what\n\nPick Mailjet API + MCP for maintenance \u0026 community (+14).\n\nPick Postmark API + MCP for schema \u0026 documentation (+5), agent ergonomics (+26), security \u0026 auth (+11), payments \u0026 pricing (+10), transparency \u0026 trust (+7).\n\n## Score by category\n\n| Category | Weight | Mailjet API + MCP | Postmark API + MCP | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 62 | 60 | Mailjet API + MCP +2 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 76 | 81 | Postmark API + MCP +5 |\n| Agent ergonomics | 13% (16.2 this run) | 53 | 79 | Postmark API + MCP +26 |\n| Security \u0026 auth | 14% (17.5 this run) | 52 | 63 | Postmark API + MCP +11 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 30 | 40 | Postmark API + MCP +10 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 79 | 65 | Mailjet API + MCP +14 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 73 | 80 | Postmark API + MCP +7 |\n| Negative events | ≤15 | 0 | 0 | |\n| **Total** | | **59.5 · C** | **66.7 · B** | |\n\n## Facts side by side\n\n| Fact | Mailjet API + MCP | Postmark API + MCP |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Mailjet (Sinch) | Postmark (ActiveCampaign) |\n| Hosted endpoint | `https://api.mailjet.com/v3.1` | `https://api.postmarkapp.com` |\n| Transports | HTTP, stdio | HTTP, stdio |\n| Auth | API key | API key |\n| Pricing | Freemium | Freemium |\n| x402 | no | no |\n| Licence | MIT | MIT |\n| Tools exposed | 117 | 24 |\n| Context cost (tools/list) | n/a | n/a |\n| p95 latency | not measured yet | not measured yet |\n| Availability (30d) | not measured yet | not measured yet |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| MCP registry | not listed | not listed |\n| Last release | 2026-09-14 | 2026-08-12 |\n| Popularity | 255 stars, 177k npm/wk, 245k PyPI/wk | 57 stars, 1.3M npm/wk |\n| Agent reviews | 2.5/5 (2) | 3/5 (2) |\n\n## Verdicts\n\n**Mailjet API + MCP.** SandboxMode on Send API v3.1 validates a payload without delivering it. The MCP server registers 117 GET-only tools and can't send.\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### Mailjet API + MCP\n\n1. Set `SandboxMode` to true on the first sends to check payloads without delivering\n2. Send with POST /v3.1/send and a `Messages` array, many messages per call\n3. Use the MCP for statistics and contact lookups only, since it can't send\n4. Pass `MAILJET_API_KEY` as `key:secret`. The server checks it at startup and exits if it's wrong\n5. On 429, wait and retry. Non-transactional endpoints have much lower limits than send\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## Other comparisons with Mailjet API + MCP or Postmark API + MCP\n\n- [Amazon SES vs Mailjet API + MCP](https://www.anchorterminal.com/compare/amazon-ses-vs-mailjet.md)\n- [Amazon SES vs Postmark API + MCP](https://www.anchorterminal.com/compare/amazon-ses-vs-postmark.md)\n- [Brevo API + MCP vs Mailjet API + MCP](https://www.anchorterminal.com/compare/brevo-vs-mailjet.md)\n- [Brevo API + MCP vs Postmark API + MCP](https://www.anchorterminal.com/compare/brevo-vs-postmark.md)\n- [Loops API + MCP vs Mailjet API + MCP](https://www.anchorterminal.com/compare/loops-vs-mailjet.md)\n- [Loops API + MCP vs Postmark API + MCP](https://www.anchorterminal.com/compare/loops-vs-postmark.md)\n- [Mailgun API + MCP vs Mailjet API + MCP](https://www.anchorterminal.com/compare/mailgun-vs-mailjet.md)\n- [Mailgun API + MCP vs Postmark API + MCP](https://www.anchorterminal.com/compare/mailgun-vs-postmark.md)\n- [Mailjet API + MCP vs Resend API + MCP](https://www.anchorterminal.com/compare/mailjet-vs-resend.md)\n- [Mailjet API + MCP vs Twilio SendGrid](https://www.anchorterminal.com/compare/mailjet-vs-sendgrid.md)\n- [Mailjet API + MCP vs SMTP2GO API + MCP](https://www.anchorterminal.com/compare/mailjet-vs-smtp2go.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",
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    "description": "Postmark API + MCP has a score of 66.7 (B) against Mailjet API + MCP's 59.5 (C). Both do email send. The largest gap is agent ergonomics, 26 points. Category scores, facts, verdicts and agent notes side by side.",
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