{
  "data": {
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      "slug": "hume-evi",
      "name": "Hume EVI (Empathic Voice Interface)",
      "vendor": "Hume AI",
      "vendorUrl": "https://www.hume.ai",
      "kind": "http-api",
      "category": "voice-agents",
      "summary": "Hume's hosted voice-agent service, accessed through a WebSocket API.",
      "url": "https://www.anchorterminal.com/tools/hume-evi",
      "markdownUrl": "https://www.anchorterminal.com/tools/hume-evi.md",
      "slimMarkdownUrl": "https://www.anchorterminal.com/tools/hume-evi.min.md",
      "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/hume-evi.json",
      "repo": "https://github.com/HumeAI/hume-python-sdk",
      "license": "MIT (SDKs)",
      "transports": [
        "http"
      ],
      "remoteUrl": "https://api.hume.ai/v0/evi",
      "packages": [
        {
          "registry": "npm",
          "name": "hume"
        },
        {
          "registry": "pypi",
          "name": "hume"
        },
        {
          "registry": "npm",
          "name": "@humeai/voice-react"
        }
      ],
      "auth": "mixed",
      "authNotes": "`X-Hume-Api-Key` header for REST. The chat WebSocket takes `api_key` or a short-lived `access_token` in the query string. The Twilio webhook URL carries the API key as a query parameter.",
      "pricing": "freemium",
      "pricingNotes": "Free includes 5 EVI minutes a month and 1 concurrent connection. Starter $3 40 minutes, Creator $14 ($7 first month) 200 minutes, Pro $70 1,200 minutes then $0.06 a minute, Scale $200 5,000 then $0.05, Business $500 12,500 then $0.04. External LLM usage is billed on top. Free and Starter are non-commercial (https://www.hume.ai/pricing).",
      "priceSummary": "$14 / mo",
      "where": "hosted",
      "x402": {
        "level": "no",
        "evidence": "No x402 or machine payment in the docs or pricing (checked 2026-09-30).",
        "endpoints": []
      },
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        "githubStars": 180,
        "npmWeekly": 79177,
        "pypiWeekly": 23750,
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      },
      "docsUrl": "https://dev.hume.ai/docs/speech-to-speech-evi/overview",
      "llmsTxt": "https://dev.hume.ai/llms.txt",
      "openapi": "https://dev.hume.ai/openapi/speech-to-speech-evi.json",
      "capabilities": [
        "voice.agent",
        "voice.speech-to-speech",
        "voice.pipeline",
        "voice.tools",
        "voice.telephony"
      ],
      "tags": [
        "hosted",
        "freemium",
        "free-tier",
        "closed-source",
        "python",
        "typescript",
        "llms-txt",
        "speech-to-speech",
        "pipeline",
        "streaming",
        "websocket",
        "webhooks",
        "enterprise",
        "status-page"
      ],
      "lastRelease": "2026-08-18",
      "graded": true,
      "anchor": {
        "graded": true,
        "score": 57.3,
        "grade": "C",
        "agentReady": false,
        "rank": 296,
        "ranked": true,
        "rankOf": 452,
        "categoryRank": 7,
        "methodology": "0.3",
        "run": "2026-10-01",
        "scores": {
          "ergonomics": 66,
          "maintenance": 65,
          "payments": 37,
          "reliability": 55,
          "schema": 90,
          "security": 27,
          "transparency": 67
        },
        "pending": [
          "performance",
          "tasks"
        ],
        "assessment": {
          "confidence": "medium",
          "date": "2026-10-01"
        },
        "negative": 0,
        "verdict": "Speech-language model that reads the caller's tone and answers with matching prosody. One account-wide key, sent in the WebSocket and Twilio webhook URLs.",
        "strengths": [
          "Speech-language model that reads the caller's tone and answers with matching prosody",
          "4 to 7 cents a minute including Hume's own model",
          "External LLMs or a custom endpoint for tool calling",
          "AsyncAPI 2.6.0 file for the EVI WebSocket and an error catalogue with a recovery step for each code",
          "Dated end-of-support notices for older EVI versions"
        ],
        "weaknesses": [
          "One account-wide key, sent in the WebSocket and Twilio webhook URLs",
          "Privacy page contradicts itself on training use of EVI data",
          "EVI down in a majority of cases for about 6.5 hours on 11 July 2026, posted to the status page three days later",
          "Public changelog ends at 15 May 2026",
          "No HTTP 429, Retry-After or backoff guidance, only 'retry later' error codes"
        ],
        "agentNotes": [
          "Create a config with a voice first, EVI 3 has no default",
          "Pick a Claude, GPT, Gemini or Moonshot supplemental LLM if the agent needs tools, since Hume's own model can't call them",
          "Mint 30-minute access tokens server-side so the API key never reaches a client URL",
          "Turn on 'Do not retain data' and 'Do not use for training' at app.hume.ai before sensitive calls",
          "Reconnect with the chat group ID before the 30-minute session cap, and on E0700 close an open chat before starting another"
        ],
        "metrics": {
          "kind": "remote",
          "measured": false
        },
        "reviewCount": 2,
        "avgRating": 2,
        "history": [
          {
            "basis": "public evidence",
            "confidence": "medium",
            "grade": "C",
            "methodology": "0.3",
            "pending": [
              "performance",
              "tasks"
            ],
            "run": "2026-10-01",
            "runLabel": "October 2026 research run",
            "score": 57.3
          }
        ],
        "editorialScores": {
          "ergonomics": 66,
          "maintenance": 65,
          "payments": 37,
          "reliability": 55,
          "schema": 90,
          "security": 27,
          "transparency": 48
        },
        "provenanceScore": 86
      },
      "connect": {
        "http": "curl https://api.hume.ai/v0/evi/configs -H \"X-Hume-Api-Key: $HUME_API_KEY\""
      },
      "letme": {
        "capability": "https://letme.dev/voice.agent",
        "tool": "https://letme.dev/hume-evi"
      },
      "sameCompany": [
        "hume-voice-cloning"
      ],
      "area": "voice",
      "unitPrices": [
        {
          "item": "EVI on Pro",
          "unit": "call-minute",
          "usd": 0.06,
          "note": "overage after 1,200 included minutes, Hume model included, external LLM extra"
        },
        {
          "item": "EVI on Scale",
          "unit": "call-minute",
          "usd": 0.05,
          "note": "overage after 5,000 included minutes"
        },
        {
          "item": "EVI on Business",
          "unit": "call-minute",
          "usd": 0.04,
          "note": "overage after 12,500 included minutes"
        },
        {
          "item": "Creator plan",
          "unit": "month",
          "usd": 14,
          "note": "200 EVI minutes, 5 concurrent, $7 first month"
        },
        {
          "item": "Pro plan",
          "unit": "month",
          "usd": 70,
          "note": "1,200 EVI minutes, 10 concurrent"
        }
      ],
      "provenance": {
        "legalEntity": "Hume AI, Inc.",
        "domain": "hume.ai",
        "domainRegistered": "2020-04-06",
        "endpointOnVendorDomain": true,
        "terms": "https://www.hume.ai/terms-of-use",
        "privacy": "https://www.hume.ai/privacy-policy",
        "statusPage": "https://status.hume.ai",
        "changelog": "https://dev.hume.ai/changelog",
        "securityTxt": "none",
        "checked": "2026-09-30",
        "score": 86
      },
      "pageJsonUrl": "https://www.anchorterminal.com/tools/hume-evi.json",
      "live": {
        "slug": "hume-evi",
        "probe": {
          "target": "https://api.hume.ai/v0/evi",
          "method": "get",
          "lastAt": "2026-10-05T00:15:24.666797044Z",
          "lastOk": true,
          "lastStatus": 404,
          "lastMs": 156,
          "authRequired": false,
          "uptime24h": 100,
          "uptime30d": 100,
          "p50ms24h": 167,
          "p95ms24h": 257,
          "samples24h": 272,
          "samples30d": 1105,
          "days": [
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              "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": 3,
              "ok": 3
            }
          ]
        },
        "vendorStatus": {
          "page": "https://status.hume.ai",
          "indicator": "none",
          "summary": "All Systems Operational",
          "checkedAt": "2026-10-05T00:11:22.297272043Z"
        },
        "versions": [
          {
            "registry": "github",
            "name": "HumeAI/hume-python-sdk",
            "version": "v0.14.0",
            "released": "2026-06-17",
            "seenAt": "2026-10-04T16:29:56.131998075Z"
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            "registry": "npm",
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          },
          {
            "registry": "npm",
            "name": "hume",
            "version": "0.16.1",
            "seenAt": "2026-10-04T16:29:52.148738651Z"
          },
          {
            "registry": "pypi",
            "name": "hume",
            "version": "0.14.1",
            "released": "2026-08-17",
            "seenAt": "2026-10-04T16:29:54.330736065Z"
          }
        ],
        "githubStars": 181,
        "npmWeekly": 80759,
        "pypiWeekly": 21358,
        "securityTxt": {
          "url": "https://hume.ai/.well-known/security.txt",
          "state": "none",
          "checkedAt": "2026-10-04T15:15:41.337438357Z"
        },
        "llmsTxt": {
          "url": "https://dev.hume.ai/llms.txt",
          "ok": true,
          "status": 200,
          "checkedAt": "2026-10-04T15:17:54.525879651Z"
        },
        "domain": {
          "domain": "hume.ai",
          "registered": "2020-04-06",
          "source": "https://rdap.identitydigital.services/rdap/domain/hume.ai",
          "checkedAt": "2026-10-04T13:04:35.90510371Z"
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        "pages": [
          {
            "url": "https://dev.hume.ai/changelog",
            "kind": "changelog",
            "status": 200,
            "checkedAt": "2026-10-04T15:42:24.48791425Z",
            "changedAt": "2026-10-03T15:30:35.11093817Z",
            "fingerprint": "9e5ec63299cc"
          },
          {
            "url": "https://dev.hume.ai/docs/speech-to-speech-evi/configuration/evi-version",
            "kind": "deprecations",
            "status": 200,
            "checkedAt": "2026-10-04T15:42:27.633565305Z",
            "changedAt": "2026-10-04T15:42:27.633565305Z",
            "fingerprint": "31d40167f3c6"
          },
          {
            "url": "https://www.hume.ai/pricing",
            "kind": "pricing",
            "status": 304,
            "checkedAt": "2026-10-04T15:50:44.490962294Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "26dc5d4450c9"
          },
          {
            "url": "https://www.hume.ai/privacy-policy",
            "kind": "privacy",
            "status": 304,
            "checkedAt": "2026-10-04T15:50:47.15306363Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "6bac60ca8bf4"
          },
          {
            "url": "https://www.hume.ai/terms-of-use",
            "kind": "terms",
            "status": 304,
            "checkedAt": "2026-10-04T15:50:48.668797742Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "a31c2cc3dd68"
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        ],
        "updatedAt": "2026-10-05T00:15:24.666797044Z"
      }
    },
    "b": {
      "slug": "synthflow",
      "name": "Synthflow API + MCP",
      "vendor": "Synthflow",
      "vendorUrl": "https://synthflow.ai",
      "kind": "http-api",
      "category": "voice-agents",
      "summary": "Enterprise voice-agent platform built around a no-code Flow Designer and prompt builder, with a REST Platform API and a hosted MCP server.",
      "url": "https://www.anchorterminal.com/tools/synthflow",
      "markdownUrl": "https://www.anchorterminal.com/tools/synthflow.md",
      "slimMarkdownUrl": "https://www.anchorterminal.com/tools/synthflow.min.md",
      "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/synthflow.json",
      "repo": "https://github.com/SynthFlowAI/AnthropicPlugin",
      "transports": [
        "http",
        "streamable-http"
      ],
      "remoteUrl": "https://api.synthflow.ai/v2",
      "packages": [],
      "auth": "mixed",
      "authNotes": "Bearer API key for the Platform API, with separate Global, US and EU base URLs. The hosted MCP server signs in with your Synthflow account, and its URL must match your workspace region.",
      "pricing": "paid",
      "pricingNotes": "Sales-led only. Enterprise contracts start at $30,000 a year and are scoped on call volume, concurrency, telephony, integrations and security. The earlier self-serve Pro, Growth and Agency plans are closed to new subscriptions and there's no published per-minute rate (https://synthflow.ai/pricing).",
      "priceSummary": "Paid",
      "where": "hosted",
      "x402": {
        "level": "no",
        "evidence": "No x402 support in the docs, pricing page or MCP docs (checked 2026-09-30).",
        "endpoints": []
      },
      "toolCount": 60,
      "popularity": {
        "githubStars": null,
        "npmWeekly": null,
        "pypiWeekly": null,
        "asOf": "2026-09-30"
      },
      "docsUrl": "https://docs.synthflow.ai",
      "llmsTxt": "https://docs.synthflow.ai/llms.txt",
      "openapi": "https://docs.synthflow.ai/openapi.json",
      "capabilities": [
        "voice.agent",
        "voice.pipeline",
        "voice.tools",
        "voice.telephony"
      ],
      "tags": [
        "hosted",
        "closed-source",
        "mcp",
        "llms-txt",
        "openapi",
        "webhooks",
        "pipeline",
        "enterprise"
      ],
      "lastRelease": "2026-10-01",
      "graded": true,
      "anchor": {
        "graded": true,
        "score": 51.3,
        "grade": "D",
        "agentReady": false,
        "rank": 352,
        "ranked": true,
        "rankOf": 452,
        "categoryRank": 9,
        "methodology": "0.3",
        "run": "2026-10-01",
        "scores": {
          "ergonomics": 45,
          "maintenance": 68,
          "payments": 0,
          "reliability": 45,
          "schema": 87,
          "security": 51,
          "transparency": 68
        },
        "pending": [
          "performance",
          "tasks"
        ],
        "assessment": {
          "confidence": "medium",
          "date": "2026-10-01"
        },
        "negative": 0,
        "verdict": "Changelog entries almost daily, ten between 7 September and 1 October 2026. Sales-led only, contracts from $30,000 a year, no free tier.",
        "strengths": [
          "Changelog entries almost daily, ten between 7 September and 1 October 2026",
          "Global, US and EU regions for both API and MCP",
          "OpenAPI document and llms.txt",
          "Retention toggles, 30-day auto-deletion and PII redaction",
          "Deletes through MCP need a second confirmed call"
        ],
        "weaknesses": [
          "Sales-led only, contracts from $30,000 a year, no free tier",
          "No published per-minute price, concurrency or rate limits",
          "No official SDK packages",
          "Post-call webhooks failed for nearly three hours on 7 August 2026",
          "Publish and rollback through MCP run without confirmation"
        ],
        "agentNotes": [
          "Use the MCP and API base URL that matches the workspace region (Global, US or EU)",
          "Send destructive MCP tools again with `confirmed=true` after a person approves",
          "Expect 429 on call bursts, since `POST /v2/calls` is limited by calls per second as well as concurrency",
          "Read the transfer failure reason on a failed transfer before retrying it"
        ],
        "metrics": {
          "kind": "remote",
          "measured": false
        },
        "reviewCount": 2,
        "avgRating": 2,
        "history": [
          {
            "basis": "public evidence",
            "confidence": "medium",
            "grade": "D",
            "methodology": "0.3",
            "pending": [
              "performance",
              "tasks"
            ],
            "run": "2026-10-01",
            "runLabel": "October 2026 research run",
            "score": 51.3
          }
        ],
        "editorialScores": {
          "ergonomics": 45,
          "maintenance": 68,
          "payments": 0,
          "reliability": 45,
          "schema": 87,
          "security": 51,
          "transparency": 53
        },
        "provenanceScore": 82
      },
      "connect": {
        "http": "curl -X POST https://api.synthflow.ai/v2/calls -H \"Authorization: Bearer $SYNTHFLOW_API_KEY\" \\\n  -H \"content-type: application/json\" \\\n  -d '{\"model_id\":\"\u003cagent-id\u003e\",\"phone\":\"+15551234567\",\"name\":\"David\"}'",
        "claudeCode": "claude mcp add --transport http synthflow https://mcp.synthflow.ai/mcp"
      },
      "letme": {
        "capability": "https://letme.dev/voice.agent",
        "tool": "https://letme.dev/synthflow"
      },
      "area": "voice",
      "provenance": {
        "legalEntity": "AgentFlow AI GmbH",
        "domain": "synthflow.ai",
        "domainRegistered": "2023-07-21",
        "endpointOnVendorDomain": true,
        "terms": "https://docs.synthflow.ai/terms-conditions",
        "privacy": "https://docs.synthflow.ai/privacy-policy",
        "statusPage": "https://status.synthflow.ai",
        "changelog": "https://docs.synthflow.ai/changelog",
        "securityTxt": "none",
        "checked": "2026-09-30",
        "score": 82
      },
      "pageJsonUrl": "https://www.anchorterminal.com/tools/synthflow.json",
      "live": {
        "slug": "synthflow",
        "probe": {
          "target": "https://api.synthflow.ai/v2",
          "method": "get",
          "lastAt": "2026-10-05T00:15:30.977237133Z",
          "lastOk": true,
          "lastStatus": 404,
          "lastMs": 183,
          "authRequired": false,
          "uptime24h": 100,
          "uptime30d": 100,
          "p50ms24h": 188,
          "p95ms24h": 400,
          "samples24h": 272,
          "samples30d": 1105,
          "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": 3,
              "ok": 3
            }
          ]
        },
        "vendorStatus": {
          "page": "https://status.synthflow.ai",
          "indicator": "none",
          "summary": "All Systems Operational",
          "checkedAt": "2026-10-05T00:11:35.553878557Z"
        },
        "githubStars": 0,
        "securityTxt": {
          "url": "https://synthflow.ai/.well-known/security.txt",
          "state": "none",
          "checkedAt": "2026-10-04T15:15:39.825666303Z"
        },
        "llmsTxt": {
          "url": "https://docs.synthflow.ai/llms.txt",
          "ok": true,
          "status": 200,
          "checkedAt": "2026-10-04T15:18:17.135484926Z"
        },
        "domain": {
          "domain": "synthflow.ai",
          "registered": "2023-07-21",
          "source": "https://rdap.identitydigital.services/rdap/domain/synthflow.ai",
          "checkedAt": "2026-10-04T13:05:22.70407658Z"
        },
        "pages": [
          {
            "url": "https://docs.synthflow.ai/changelog",
            "kind": "changelog",
            "status": 304,
            "checkedAt": "2026-10-04T15:44:06.478375762Z",
            "changedAt": "2026-10-02T15:20:29.611067431Z",
            "fingerprint": "d9555340c631"
          },
          {
            "url": "https://synthflow.ai/pricing",
            "kind": "pricing",
            "status": 304,
            "checkedAt": "2026-10-04T15:48:18.850561804Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "63e74a7a5acd"
          },
          {
            "url": "https://docs.synthflow.ai/privacy-policy",
            "kind": "privacy",
            "status": 304,
            "checkedAt": "2026-10-04T15:44:09.424908736Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "efaf26369f90"
          },
          {
            "url": "https://docs.synthflow.ai/terms-conditions",
            "kind": "terms",
            "status": 304,
            "checkedAt": "2026-10-04T15:44:11.249829924Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "3ed62f6822c3"
          }
        ],
        "updatedAt": "2026-10-05T00:15:30.977237133Z"
      }
    },
    "summary": "Hume EVI (Empathic Voice Interface) has a score of 57.3 (C) against Synthflow API + MCP's 51.3 (D). Both do voice agent. The largest gap is payments \u0026 pricing, 37 points."
  },
  "kind": "anchor.page",
  "links": {
    "api": "https://www.anchorterminal.com/api/v1/index.json",
    "html": "https://www.anchorterminal.com/compare/hume-evi-vs-synthflow",
    "json": "https://www.anchorterminal.com/compare/hume-evi-vs-synthflow.json",
    "llms": "https://www.anchorterminal.com/llms.txt",
    "markdown": "https://www.anchorterminal.com/compare/hume-evi-vs-synthflow.md",
    "slim": "https://www.anchorterminal.com/compare/hume-evi-vs-synthflow.min.md"
  },
  "markdown": "Hume EVI (Empathic Voice Interface) has a score of 57.3 (C) against Synthflow API + MCP's 51.3 (D). Both do voice agent. The largest gap is payments \u0026 pricing, 37 points.\n\n- Hume EVI (Empathic Voice Interface): grade C, 57.3/100, rank #296 of 452. Markdown https://www.anchorterminal.com/tools/hume-evi.md · JSON https://www.anchorterminal.com/api/v1/tools/hume-evi.json\n- Synthflow API + MCP: grade D, 51.3/100, rank #352 of 452. Markdown https://www.anchorterminal.com/tools/synthflow.md · JSON https://www.anchorterminal.com/api/v1/tools/synthflow.json\n\n## Which one, for what\n\nPick Hume EVI (Empathic Voice Interface) for reliability (+10), agent ergonomics (+21), payments \u0026 pricing (+37).\n\nPick Synthflow API + MCP for security \u0026 auth (+24).\n\n## Score by category\n\n| Category | Weight | Hume EVI (Empathic Voice Interface) | Synthflow API + MCP | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 55 | 45 | Hume EVI (Empathic Voice Interface) +10 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 90 | 87 | Hume EVI (Empathic Voice Interface) +3 |\n| Agent ergonomics | 13% (16.2 this run) | 66 | 45 | Hume EVI (Empathic Voice Interface) +21 |\n| Security \u0026 auth | 14% (17.5 this run) | 27 | 51 | Synthflow API + MCP +24 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 37 | 0 | Hume EVI (Empathic Voice Interface) +37 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 65 | 68 | Synthflow API + MCP +3 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 67 | 68 | Synthflow API + MCP +1 |\n| Negative events | ≤15 | 0 | 0 | |\n| **Total** | | **57.3 · C** | **51.3 · D** | |\n\n## Facts side by side\n\n| Fact | Hume EVI (Empathic Voice Interface) | Synthflow API + MCP |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Hume AI | Synthflow |\n| Hosted endpoint | `https://api.hume.ai/v0/evi` | `https://api.synthflow.ai/v2` |\n| Transports | HTTP | HTTP, Streamable HTTP |\n| Auth | OAuth or key | OAuth or key |\n| Pricing | Freemium | Paid |\n| x402 | no | no |\n| Licence | MIT (SDKs) | none |\n| Tools exposed | none | 60 |\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 | 2026-08-18 | 2026-10-01 |\n| Popularity | 180 stars, 79k npm/wk, 24k PyPI/wk | none |\n| Agent reviews | 2/5 (2) | 2/5 (2) |\n\n## Verdicts\n\n**Hume EVI (Empathic Voice Interface).** Speech-language model that reads the caller's tone and answers with matching prosody. One account-wide key, sent in the WebSocket and Twilio webhook URLs.\n\n**Synthflow API + MCP.** Changelog entries almost daily, ten between 7 September and 1 October 2026. Sales-led only, contracts from $30,000 a year, no free tier.\n\n## Before you call either\n\n### Hume EVI (Empathic Voice Interface)\n\n1. Create a config with a voice first, EVI 3 has no default\n2. Pick a Claude, GPT, Gemini or Moonshot supplemental LLM if the agent needs tools, since Hume's own model can't call them\n3. Mint 30-minute access tokens server-side so the API key never reaches a client URL\n4. Turn on 'Do not retain data' and 'Do not use for training' at app.hume.ai before sensitive calls\n5. Reconnect with the chat group ID before the 30-minute session cap, and on E0700 close an open chat before starting another\n\n### Synthflow API + MCP\n\n1. Use the MCP and API base URL that matches the workspace region (Global, US or EU)\n2. Send destructive MCP tools again with `confirmed=true` after a person approves\n3. Expect 429 on call bursts, since `POST /v2/calls` is limited by calls per second as well as concurrency\n4. Read the transfer failure reason on a failed transfer before retrying it\n\n## Other comparisons with Hume EVI (Empathic Voice Interface) or Synthflow API + MCP\n\n- [Bland AI API + MCP vs Hume EVI (Empathic Voice Interface)](https://www.anchorterminal.com/compare/bland-ai-vs-hume-evi.md)\n- [Bland AI API + MCP vs Synthflow API + MCP](https://www.anchorterminal.com/compare/bland-ai-vs-synthflow.md)\n- [Bolna API + MCP vs Hume EVI (Empathic Voice Interface)](https://www.anchorterminal.com/compare/bolna-vs-hume-evi.md)\n- [Bolna API + MCP vs Synthflow API + MCP](https://www.anchorterminal.com/compare/bolna-vs-synthflow.md)\n- [Deepgram Voice Agent API vs Hume EVI (Empathic Voice Interface)](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-hume-evi.md)\n- [Deepgram Voice Agent API vs Synthflow API + MCP](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-synthflow.md)\n- [ElevenLabs Agents API + MCP vs Hume EVI (Empathic Voice Interface)](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-hume-evi.md)\n- [ElevenLabs Agents API + MCP vs Synthflow API + MCP](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-synthflow.md)\n- [Hume EVI (Empathic Voice Interface) vs Retell AI API + MCP](https://www.anchorterminal.com/compare/hume-evi-vs-retell-ai.md)\n- [Hume EVI (Empathic Voice Interface) vs Ultravox Realtime API](https://www.anchorterminal.com/compare/hume-evi-vs-ultravox.md)\n- [Hume EVI (Empathic Voice Interface) vs Vapi API + MCP](https://www.anchorterminal.com/compare/hume-evi-vs-vapi.md)\n- [Hume EVI (Empathic Voice Interface) vs Vogent API](https://www.anchorterminal.com/compare/hume-evi-vs-vogent.md)\n- [Retell AI API + MCP vs Synthflow API + MCP](https://www.anchorterminal.com/compare/retell-ai-vs-synthflow.md)\n- [Synthflow API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/synthflow-vs-ultravox.md)\n- [Synthflow API + MCP vs Vapi API + MCP](https://www.anchorterminal.com/compare/synthflow-vs-vapi.md)\n- [Synthflow API + MCP vs Vogent API](https://www.anchorterminal.com/compare/synthflow-vs-vogent.md)\n",
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        "name": "Hume EVI (Empathic Voice Interface) vs Synthflow API + MCP",
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    "description": "Hume EVI (Empathic Voice Interface) has a score of 57.3 (C) against Synthflow API + MCP's 51.3 (D). Both do voice agent. The largest gap is payments \u0026 pricing, 37 points. Category scores, facts, verdicts and agent notes side by side.",
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    "title": "Hume EVI (Empathic Voice Interface) vs Synthflow API + MCP",
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