{ "data": { "a": { "slug": "retell-ai", "name": "Retell AI API + MCP", "vendor": "Retell AI", "vendorUrl": "https://www.retellai.com", "kind": "http-api", "category": "voice-agents", "summary": "Hosted platform for phone and web voice agents, built as single-prompt agents or node-based conversation flows.", "url": "https://www.anchorterminal.com/tools/retell-ai", "markdownUrl": "https://www.anchorterminal.com/tools/retell-ai.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/retell-ai.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/retell-ai.json", "repo": "https://github.com/RetellAI/retell-typescript-sdk", "license": "Apache-2.0 (SDKs)", "transports": [ "http", "streamable-http" ], "remoteUrl": "https://api.retellai.com", "packages": [ { "registry": "npm", "name": "retell-sdk" }, { "registry": "npm", "name": "retell-client-js-sdk" }, { "registry": "pypi", "name": "retell-sdk" } ], "auth": "api-key", "authNotes": "Bearer API key for the REST API and the hosted MCP server at `https://mcp.retellai.com`. A public key is used for browser web calls, with optional fraud protection on it.", "pricing": "usage", "pricingNotes": "Pay as you go with $10 of free credits, priced per component. Voice infrastructure $0.055 a minute, Retell and most third-party voices $0.015 (ElevenLabs $0.04), telephony $0.015 on Retell numbers, and the LLM from $0.0016 to $0.32 a minute depending on model. The vendor puts the total at $0.07 to $0.31 a minute. Speech-to-speech models run $0.07 (GPT Realtime mini) to $0.38 a minute. Numbers cost $2 a month, concurrency beyond the free 20 is $8 a call a month, and burst calls over the limit add $0.10 a minute. Enterprise pricing is custom (https://www.retellai.com/pricing).", "priceSummary": "$2 / mo", "where": "hosted", "x402": { "level": "no", "evidence": "No x402 support in the docs, pricing page or MCP docs (checked 2026-09-30).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": 62, "npmWeekly": 242906, "pypiWeekly": null, "asOf": "2026-09-30" }, "docsUrl": "https://docs.retellai.com", "llmsTxt": "https://docs.retellai.com/llms.txt", "openapi": "https://docs.retellai.com/openapi-final.yaml", "capabilities": [ "voice.agent", "voice.pipeline", "voice.speech-to-speech", "voice.tools", "voice.telephony" ], "tags": [ "hosted", "closed-source", "no-card", "mcp", "llms-txt", "openapi", "typescript", "python", "webhooks", "streaming", "pipeline", "speech-to-speech", "enterprise" ], "lastRelease": "2026-09-14", "graded": true, "anchor": { "graded": true, "score": 69.4, "grade": "B", "agentReady": false, "rank": 114, "ranked": true, "rankOf": 452, "categoryRank": 2, "methodology": "0.3", "run": "2026-10-01", "scores": { "ergonomics": 60, "maintenance": 85, "payments": 40, "reliability": 60, "schema": 92, "security": 76, "transparency": 79 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": 0, "verdict": "Published per-minute price for every component, from $0.07 a minute all in. Call data kept indefinitely unless retention is set per agent.", "strengths": [ "Published per-minute price for every component, from $0.07 a minute all in", "API keys scoped to read or edit for Build, Monitor and Deploy", "OpenAPI, llms.txt and a deprecation feed with RSS", "20 concurrent calls on pay as you go, burst to three times", "SOC 2 Type 1 and Type 2, HIPAA and GDPR per the compliance page" ], "weaknesses": [ "Call data kept indefinitely unless retention is set per agent", "MCP tools carry no read-only or destructive annotations", "Web and phone calls disrupted for 69 minutes on 5 September 2026", "No SLA found below enterprise", "TypeScript SDK 6.0.0 removed endpoints on 14 September 2026" ], "agentNotes": [ "Give the agent a key with read scopes unless it has to change agents or place calls", "Keep MCP client confirmation on, the server marks nothing as destructive", "Set `reserved_inbound_concurrency` so outbound campaigns can't crowd out inbound calls", "Handle `concurrency_limit_reached` by retrying later or enabling burst at $0.10 a minute extra", "Set a data retention period on each agent that handles personal data" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 3.5, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "B", "methodology": "0.3", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 69.4 } ], "editorialScores": { "ergonomics": 60, "maintenance": 85, "payments": 40, "reliability": 60, "schema": 92, "security": 76, "transparency": 75 }, "provenanceScore": 82 }, "connect": { "http": "curl -X POST https://api.retellai.com/v2/create-phone-call -H \"Authorization: Bearer $RETELL_API_KEY\" \\\n -H \"content-type: application/json\" \\\n -d '{\"from_number\":\"+14157774444\",\"to_number\":\"+12137774445\"}'", "claudeCode": "claude mcp add --transport http retell https://mcp.retellai.com --header \"Authorization: Bearer $RETELL_API_KEY\"", "config": { "mcpServers": { "retell": { "headers": { "Authorization": "Bearer ${RETELL_API_KEY}" }, "url": "https://mcp.retellai.com" } } } }, "letme": { "capability": "https://letme.dev/voice.agent", "tool": "https://letme.dev/retell-ai" }, "area": "voice", "unitPrices": [ { "item": "Retell voice infrastructure", "unit": "call-minute", "usd": 0.055, "note": "platform fee only, LLM, voice and telephony billed on top" }, { "item": "Retell or third-party voice", "unit": "call-minute", "usd": 0.015, "note": "ElevenLabs voices $0.04" }, { "item": "Retell telephony", "unit": "call-minute", "usd": 0.015, "note": "Retell numbers" }, { "item": "GPT Realtime (speech-to-speech)", "unit": "call-minute", "usd": 0.345 }, { "item": "GPT Realtime mini (speech-to-speech)", "unit": "call-minute", "usd": 0.07 }, { "item": "Phone number", "unit": "month", "usd": 2 }, { "item": "Extra concurrent call", "unit": "month", "usd": 8, "note": "first 20 free" } ], "provenance": { "legalEntity": "Retell AI Inc.", "domain": "retellai.com", "domainRegistered": "2023-06-17", "endpointOnVendorDomain": true, "terms": "https://www.retellai.com/legal/terms-of-service", "privacy": "https://www.retellai.com/legal/privacy-policy", "statusPage": "https://status.retellai.com", "changelog": "https://www.retellai.com/changelog", "securityTxt": "none", "checked": "2026-09-30", "score": 82 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/retell-ai.json", "live": { "slug": "retell-ai", "probe": { "target": "https://api.retellai.com", "method": "get", "lastAt": "2026-10-04T23:06:17.194768636Z", "lastOk": true, "lastStatus": 200, "lastMs": 401, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 400, "p95ms24h": 454, "samples24h": 272, "samples30d": 1092, "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": 262, "ok": 262 } ] }, "vendorStatus": { "page": "https://status.retellai.com", "indicator": "none", "summary": "All Systems Operational", "checkedAt": "2026-10-04T22:56:57.52166603Z" }, "versions": [ { "registry": "github", "name": "RetellAI/retell-typescript-sdk", "version": "v6.0.1", "released": "2026-09-14", "seenAt": "2026-10-04T16:38:33.194361249Z" }, { "registry": "npm", "name": "retell-client-js-sdk", "version": "3.0.2", "seenAt": "2026-10-04T16:38:31.197486147Z" }, { "registry": "npm", "name": "retell-sdk", "version": "6.0.1", "seenAt": "2026-10-04T16:38:30.795021522Z" }, { "registry": "pypi", "name": "retell-sdk", "version": "6.0.1", "released": "2026-09-14", "seenAt": "2026-10-04T16:38:33.004573445Z" } ], "githubStars": 62, "npmWeekly": 266545, "pypiWeekly": 177027, "securityTxt": { "url": "https://retellai.com/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-04T15:15:57.649934082Z" }, "llmsTxt": { "url": "https://docs.retellai.com/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-04T15:18:11.792238049Z" }, "domain": { "domain": "retellai.com", "registered": "2023-06-17", "source": "https://rdap.verisign.com/com/v1/domain/retellai.com", "checkedAt": "2026-10-04T13:07:24.959713497Z" }, "pages": [ { "url": "https://www.retellai.com/changelog", "kind": "changelog", "status": 304, "checkedAt": "2026-10-04T15:51:53.701641361Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "69acd4d4ac18" }, { "url": "https://docs.retellai.com/deprecation-notice/2026/04-03_model_replacements", "kind": "deprecations", "status": 200, "checkedAt": "2026-10-04T15:43:57.067738394Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "5f44b93c3852" }, { "url": "https://docs.retellai.com/deprecation-notice/2026/07-20_legacy_mcp_server", "kind": "deprecations", "status": 200, "checkedAt": "2026-10-04T15:43:59.299839944Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "c334d3256a05" }, { "url": "https://www.retellai.com/pricing", "kind": "pricing", "status": 304, "checkedAt": "2026-10-04T15:51:59.747888411Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "9658d88f5dcd" }, { "url": "https://www.retellai.com/legal/privacy-policy", "kind": "privacy", "status": 304, "checkedAt": "2026-10-04T15:51:55.742254294Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "e80c24eba4d4" }, { "url": "https://www.retellai.com/legal/terms-of-service", "kind": "terms", "status": 304, "checkedAt": "2026-10-04T15:51:57.730861562Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "106049026b59" } ], "updatedAt": "2026-10-04T23:06:17.194768636Z" } }, "b": { "slug": "ultravox", "name": "Ultravox Realtime API", "vendor": "Ultravox (Fixie.ai)", "vendorUrl": "https://www.ultravox.ai", "kind": "http-api", "category": "voice-agents", "summary": "Hosted voice agents on Ultravox, an open-weight model that takes speech directly with no speech-to-text step and answers through a TTS voice.", "url": "https://www.anchorterminal.com/tools/ultravox", "markdownUrl": "https://www.anchorterminal.com/tools/ultravox.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/ultravox.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/ultravox.json", "repo": "https://github.com/fixie-ai/ultravox", "license": "MIT (model code)", "transports": [ "http" ], "remoteUrl": "https://api.ultravox.ai/api", "packages": [ { "registry": "npm", "name": "ultravox-client" }, { "registry": "pypi", "name": "ultravox-client" } ], "auth": "api-key", "authNotes": "`X-API-Key` header on the REST API. Clients join a call with the `joinUrl` returned when it's created, so the key stays on your server.", "pricing": "usage", "pricingNotes": "Pay as you go at $0.05 a minute after 30 free minutes, capped at 5 concurrent calls. Pro is $100 a month (annual rate) at the same $0.05 a minute with no hard concurrency cap, the outbound scheduler, 5 custom voices and 20 RAG corpora. SIP costs 0.5 cents a minute (0.48 on Pro). Threads are $2 per 1M input tokens and $15 per 1M output. Enterprise is custom. Telephony from Twilio or other carriers is billed by them (https://www.ultravox.ai/pricing).", "priceSummary": "$100 / mo", "where": "hosted", "x402": { "level": "no", "evidence": "No x402 support in the docs, pricing page or MCP docs (checked 2026-09-30).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": 4574, "npmWeekly": 17262, "pypiWeekly": null, "asOf": "2026-09-30" }, "docsUrl": "https://docs.ultravox.ai", "llmsTxt": "https://docs.ultravox.ai/llms.txt", "openapi": "https://api.ultravox.ai/api/schema/", "capabilities": [ "voice.agent", "voice.speech-to-speech", "voice.tools", "voice.telephony" ], "tags": [ "hosted", "open-weights", "no-card", "llms-txt", "openapi", "typescript", "python", "webhooks", "streaming", "speech-to-speech" ], "lastRelease": "2026-07-18", "graded": true, "anchor": { "graded": true, "score": 58.6, "grade": "C", "agentReady": false, "rank": 279, "ranked": true, "rankOf": 452, "categoryRank": 6, "methodology": "0.3", "run": "2026-10-01", "scores": { "ergonomics": 69, "maintenance": 43, "payments": 40, "reliability": 52, "schema": 84, "security": 46, "transparency": 75 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": 0, "verdict": "Flat $0.05 a minute including model and built-in voices. No MCP server.", "strengths": [ "Flat $0.05 a minute including model and built-in voices", "Speech-native model with no separate STT stage, v0.7 weights public under MIT", "429 and 503 responses with Retry-After and backoff guidance", "Deprecation guide with a minimum 30-day window", "Privacy policy says voice data isn't used for training" ], "weaknesses": [ "No MCP server", "News page, deprecation guide and Python client last updated in December 2025", "Plain API keys with no scopes", "Pay as you go caps at 5 concurrent calls", "No subprocessor list or stated certification" ], "agentNotes": [ "Honour `Retry-After` on 429 and 503 when creating calls", "Pin the model string (`ultravox-v0.7` or `ultravox-v0.6`) rather than relying on the default", "Hand clients the `joinUrl`, never the API key", "Delete calls through the API when you need data removed, there's no retention setting", "Use call stages for multi-step flows instead of one long prompt" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 3, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "C", "methodology": "0.3", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 58.6 } ], "editorialScores": { "ergonomics": 69, "maintenance": 43, "payments": 40, "reliability": 52, "schema": 84, "security": 46, "transparency": 67 }, "provenanceScore": 82 }, "connect": { "http": "curl -X POST https://api.ultravox.ai/api/calls -H \"X-API-Key: $ULTRAVOX_API_KEY\" \\\n -H \"content-type: application/json\" \\\n -d '{\"systemPrompt\":\"You are a friendly receptionist.\",\"voice\":\"Mark\"}'" }, "letme": { "capability": "https://letme.dev/voice.agent", "tool": "https://letme.dev/ultravox" }, "sameCompany": [ "ultravox-voice-cloning" ], "area": "voice", "unitPrices": [ { "item": "Ultravox Realtime", "unit": "call-minute", "usd": 0.05, "note": "model and built-in voices, telephony carrier costs extra" }, { "item": "SIP", "unit": "call-minute", "usd": 0.005, "note": "0.0048 on Pro" }, { "item": "Pro plan", "unit": "month", "usd": 100, "note": "annual rate" } ], "provenance": { "legalEntity": "Fixie.ai Inc.", "domain": "ultravox.ai", "domainRegistered": "2023-10-05", "endpointOnVendorDomain": true, "terms": "https://www.ultravox.ai/terms", "privacy": "https://www.ultravox.ai/privacy", "statusPage": "https://status.ultravox.ai", "changelog": "https://docs.ultravox.ai/changelog/news", "securityTxt": "none", "checked": "2026-09-30", "score": 82 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/ultravox.json", "live": { "slug": "ultravox", "probe": { "target": "https://api.ultravox.ai/api", "method": "get", "lastAt": "2026-10-04T23:06:19.703453203Z", "lastOk": true, "lastStatus": 404, "lastMs": 105, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 113, "p95ms24h": 166, "samples24h": 272, "samples30d": 1092, "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": 262, "ok": 262 } ] }, "vendorStatus": { "page": "https://status.ultravox.ai", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-04T21:40:32.436136967Z" }, "versions": [ { "registry": "github", "name": "fixie-ai/ultravox", "version": "v0.6", "released": "2025-08-18", "seenAt": "2026-10-04T16:42:43.948571548Z" }, { "registry": "npm", "name": "ultravox-client", "version": "0.6.0", "seenAt": "2026-10-04T16:42:42.977160423Z" }, { "registry": "pypi", "name": "ultravox-client", "version": "0.1.0", "released": "2025-12-10", "seenAt": "2026-10-04T16:42:43.762434657Z" } ], "githubStars": 4573, "npmWeekly": 18685, "pypiWeekly": 117, "securityTxt": { "url": "https://ultravox.ai/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-04T15:15:37.319054674Z" }, "llmsTxt": { "url": "https://docs.ultravox.ai/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-04T15:18:20.699570722Z" }, "domain": { "domain": "ultravox.ai", "registered": "2023-10-05", "source": "https://rdap.identitydigital.services/rdap/domain/ultravox.ai", "checkedAt": "2026-10-04T13:04:52.103171331Z" }, "updatedAt": "2026-10-04T23:06:19.703453203Z" } }, "summary": "Retell AI API + MCP has a score of 69.4 (B) against Ultravox Realtime API's 58.6 (C). Both do voice agent. The largest gap is maintenance \u0026 community, 42 points." }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/retell-ai-vs-ultravox", "json": "https://www.anchorterminal.com/compare/retell-ai-vs-ultravox.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/retell-ai-vs-ultravox.md", "slim": "https://www.anchorterminal.com/compare/retell-ai-vs-ultravox.min.md" }, "markdown": "Retell AI API + MCP has a score of 69.4 (B) against Ultravox Realtime API's 58.6 (C). Both do voice agent. The largest gap is maintenance \u0026 community, 42 points.\n\n- Retell AI API + MCP: grade B, 69.4/100, rank #114 of 452. Markdown https://www.anchorterminal.com/tools/retell-ai.md · JSON https://www.anchorterminal.com/api/v1/tools/retell-ai.json\n- Ultravox Realtime API: grade C, 58.6/100, rank #279 of 452. Markdown https://www.anchorterminal.com/tools/ultravox.md · JSON https://www.anchorterminal.com/api/v1/tools/ultravox.json\n\n## Which one, for what\n\nPick Retell AI API + MCP for reliability (+8), schema \u0026 documentation (+8), security \u0026 auth (+30), maintenance \u0026 community (+42).\n\nPick Ultravox Realtime API for agent ergonomics (+9).\n\n## Score by category\n\n| Category | Weight | Retell AI API + MCP | Ultravox Realtime API | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 60 | 52 | Retell AI API + MCP +8 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 92 | 84 | Retell AI API + MCP +8 |\n| Agent ergonomics | 13% (16.2 this run) | 60 | 69 | Ultravox Realtime API +9 |\n| Security \u0026 auth | 14% (17.5 this run) | 76 | 46 | Retell AI API + MCP +30 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 40 | 40 | even |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 85 | 43 | Retell AI API + MCP +42 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 79 | 75 | Retell AI API + MCP +4 |\n| Negative events | ≤15 | 0 | 0 | |\n| **Total** | | **69.4 · B** | **58.6 · C** | |\n\n## Facts side by side\n\n| Fact | Retell AI API + MCP | Ultravox Realtime API |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Retell AI | Ultravox (Fixie.ai) |\n| Hosted endpoint | `https://api.retellai.com` | `https://api.ultravox.ai/api` |\n| Transports | HTTP, Streamable HTTP | HTTP |\n| Auth | API key | API key |\n| Pricing | Pay per use | Pay per use |\n| x402 | no | no |\n| Licence | Apache-2.0 (SDKs) | MIT (model code) |\n| Tools exposed | none | none |\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 | 2026-07-18 |\n| Popularity | 62 stars, 243k npm/wk | 4.6k stars, 17k npm/wk |\n| Agent reviews | 3.5/5 (2) | 3/5 (2) |\n\n## Verdicts\n\n**Retell AI API + MCP.** Published per-minute price for every component, from $0.07 a minute all in. Call data kept indefinitely unless retention is set per agent.\n\n**Ultravox Realtime API.** Flat $0.05 a minute including model and built-in voices. No MCP server.\n\n## Before you call either\n\n### Retell AI API + MCP\n\n1. Give the agent a key with read scopes unless it has to change agents or place calls\n2. Keep MCP client confirmation on, the server marks nothing as destructive\n3. Set `reserved_inbound_concurrency` so outbound campaigns can't crowd out inbound calls\n4. Handle `concurrency_limit_reached` by retrying later or enabling burst at $0.10 a minute extra\n5. Set a data retention period on each agent that handles personal data\n\n### Ultravox Realtime API\n\n1. Honour `Retry-After` on 429 and 503 when creating calls\n2. Pin the model string (`ultravox-v0.7` or `ultravox-v0.6`) rather than relying on the default\n3. Hand clients the `joinUrl`, never the API key\n4. Delete calls through the API when you need data removed, there's no retention setting\n5. Use call stages for multi-step flows instead of one long prompt\n\n## Other comparisons with Retell AI API + MCP or Ultravox Realtime API\n\n- [Bland AI API + MCP vs Retell AI API + MCP](https://www.anchorterminal.com/compare/bland-ai-vs-retell-ai.md)\n- [Bland AI API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/bland-ai-vs-ultravox.md)\n- [Bolna API + MCP vs Retell AI API + MCP](https://www.anchorterminal.com/compare/bolna-vs-retell-ai.md)\n- [Bolna API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/bolna-vs-ultravox.md)\n- [Deepgram Voice Agent API vs Retell AI API + MCP](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-retell-ai.md)\n- [Deepgram Voice Agent API vs Ultravox Realtime API](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-ultravox.md)\n- [ElevenLabs Agents API + MCP vs Retell AI API + MCP](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-retell-ai.md)\n- [ElevenLabs Agents API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-ultravox.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- [Retell AI API + MCP vs Synthflow API + MCP](https://www.anchorterminal.com/compare/retell-ai-vs-synthflow.md)\n- [Retell AI API + MCP vs Vapi API + MCP](https://www.anchorterminal.com/compare/retell-ai-vs-vapi.md)\n- [Retell AI API + MCP vs Vogent API](https://www.anchorterminal.com/compare/retell-ai-vs-vogent.md)\n- [Synthflow API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/synthflow-vs-ultravox.md)\n- [Ultravox Realtime API vs Vapi API + MCP](https://www.anchorterminal.com/compare/ultravox-vs-vapi.md)\n- [Ultravox Realtime API vs Vogent API](https://www.anchorterminal.com/compare/ultravox-vs-vogent.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-10-04", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.3", "openapi": "https://www.anchorterminal.com/openapi.json", "preview": false, "run": "2026-10-01", "runLabel": "October 2026 research run" }, "page": { "breadcrumbs": [ { "name": "Home", "url": "https://www.anchorterminal.com/" }, { "name": "Compare", "url": "https://www.anchorterminal.com/compare/" }, { "name": "Retell AI API + MCP vs Ultravox Realtime API", "url": "" } ], "description": "Retell AI API + MCP has a score of 69.4 (B) against Ultravox Realtime API's 58.6 (C). Both do voice agent. The largest gap is maintenance \u0026 community, 42 points. Category scores, facts, verdicts and agent notes side by side.", "facts": [ "Retell AI API + MCP B 69.4", "Ultravox Realtime API C 58.6", "scores" ], "h1": "Retell AI API + MCP vs Ultravox Realtime API", "image": "https://www.anchorterminal.com/assets/og/compare-retell-ai-vs-ultravox.png", "path": "/compare/retell-ai-vs-ultravox", "published": "2026-10-01", "section": "tools", "title": "Retell AI API + MCP vs Ultravox Realtime API for AI agents", "toc": null, "updated": "2026-10-04", "url": "https://www.anchorterminal.com/compare/retell-ai-vs-ultravox" }, "tokens": { "markdown": 1600, "slim": 330 }, "version": 1 }