{ "data": { "a": { "slug": "inworld-tts", "name": "Inworld Realtime TTS-2", "vendor": "Inworld AI", "vendorUrl": "https://inworld.ai", "kind": "model", "category": "text-to-speech", "summary": "Inworld's hosted text-to-speech models, `inworld-tts-2` and `inworld-tts-2-flash`, over REST, HTTP streaming, WebSocket, async jobs and an OpenAI-compatible endpoint. TTS-2 takes bracketed steering, and an opt-in Reasoning step writes the delivery direction itself.", "url": "https://www.anchorterminal.com/tools/inworld-tts", "markdownUrl": "https://www.anchorterminal.com/tools/inworld-tts.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/inworld-tts.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/inworld-tts.json", "license": "Proprietary service under Inworld's Terms of Service. The Node.js SDK `@inworld/tts` and the CLI `@inworld/cli` are MIT on npm", "transports": [ "http", "websocket" ], "remoteUrl": "https://api.inworld.ai", "packages": [ { "registry": "npm", "name": "@inworld/tts" }, { "registry": "pypi", "name": "inworld-tts" }, { "registry": "npm", "name": "@inworld/cli" } ], "auth": "api-key", "authNotes": "Every call sends `Authorization: Basic` with the Base64 `key_id:secret` credential copied from the Portal or printed by the CLI. Keys belong to a workspace, are deleted to revoke, and have write toggles only for the Voice and Router APIs, so no key is limited to TTS. Browser and mobile clients use single-use tokens minted server-side, valid 15 minutes by default.", "pricing": "freemium", "pricingNotes": "TTS-2 costs $25 per million characters on the free On-Demand plan, falling to $20, $17.50, $15 and $12.50 on the $25, $100, $300 and $1,500 monthly plans, and from $5 on Enterprise. TTS-2 Flash runs $15 down to $7. On-Demand includes up to 70 minutes of TTS with no card. Steering tags count as characters, while `synthesisContext` and `reasoningContext` aren't billed. Batch costs 20 per cent less (checked 2026-10-30).", "priceSummary": "$25 / mo", "where": "hosted", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in llms.txt, the TTS docs, the billing page or the pricing page (checked 2026-10-30). Usage is drawn from prepaid plan credits, card top-ups of at least $10 or auto-reload.", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": null, "npmWeekly": 3632, "pypiWeekly": null, "asOf": "2026-10-30" }, "docsUrl": "https://docs.inworld.ai/tts/tts", "llmsTxt": "https://docs.inworld.ai/llms.txt", "capabilities": [ "speech.tts", "speech.streaming", "speech.voices", "speech.ssml", "speech.languages", "speech.batch", "voice.clone", "voice.design" ], "tags": [ "hosted", "official", "closed-source", "freemium", "free-tier", "no-card", "llms-txt", "streaming", "openai-compatible", "reasoning", "multilingual", "async-jobs", "batch", "typescript", "python", "cli", "mcp", "status-page", "soc2", "enterprise" ], "lastRelease": "2026-10-28", "graded": true, "anchor": { "graded": true, "score": 58.3, "grade": "C", "agentReady": false, "rank": 687, "ranked": true, "rankOf": 1243, "categoryRank": 10, "methodology": "0.7", "run": "2026-10-01", "scores": { "ergonomics": 68, "maintenance": 68, "payments": 40, "reliability": 62, "schema": 60, "security": 61, "transparency": 63 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-30" }, "negative": -2, "negativeNotes": [ "30 October 2026. Inworld's Realtime TTS-2 page shows Realtime TTS-2 as #1 for voice quality on the Artificial Analysis Speech Arena and says the ranks come from the live arena, not hardcoded. Artificial Analysis's provider-voice leaderboard on the same day put Realtime TTS-2 8th (Elo 1,267) behind Eleven v4 Turbo (1,336). The page also says the table was verified in May 2026. The deduction lapses if the page is corrected or the rank returns. Sources: https://inworld.ai/blog/realtime-tts-2 and https://artificialanalysis.ai/text-to-speech/leaderboard/provider-voice (-2)" ], "verdict": "TTS-2 takes bracketed steering, and opt-in Reasoning writes a delivery direction from the text and up to 600 characters of context, returning it in the response. Per-character prices are public and the free plan needs no card. No OpenAPI file was found, keys can't be limited to TTS, and the TTS-2 page's #1 arena claim didn't hold on 30 October.", "bestFor": "Agents that generate replies or stories at runtime and want delivery chosen from context without writing tags, and for per-message or pre-generated audio.", "strengths": [ "Reasoning returns the direction it applied as `reasoningInstruction`, so an agent can log it and reuse it as an inline tag", "Per-character prices are public, from $25 per million characters for TTS-2 on the free plan to $12.50 on Growth", "REST, HTTP streaming, WebSocket, async jobs and an OpenAI-compatible `/v1/audio/speech` endpoint", "llms.txt, Markdown twins of every page and a keyless docs MCP server at docs.inworld.ai/mcp", "Single-use client tokens, 15 minutes by default, keep the API key off browsers and phones" ], "weaknesses": [ "No OpenAPI or other machine-readable contract was found for the TTS API", "API keys can't be limited to TTS. Write toggles cover only the Voice and Router APIs", "The 28 October model update replaced `inworld-tts-2` in place, with no dated snapshot to pin", "Zero data retention is Enterprise only or a Growth add-on, and the SLA is Enterprise only", "The TTS-2 page claims #1 on the Artificial Analysis Speech Arena, which ranked it 8th on 30 October 2026" ], "agentNotes": [ "Send the copied Base64 credential as-is in `Authorization: Basic`. Don't encode it again.", "Set `modelId` explicitly, because SDK defaults may name deprecated models.", "Keep text under 2,000 UTF-16 units on `/tts/v1/voice` and 4,000 on `voice:stream`, or use an async job.", "Turn on Reasoning with `synthesisContext.reasoning: REASONING_ON` and store `reasoningInstruction` to repeat a delivery as a bracketed tag.", "On 429 or error code 8, back off exponentially with jitter. No Retry-After header is documented." ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "C", "methodology": "0.7", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 58.3 } ], "editorialScores": { "ergonomics": 68, "maintenance": 68, "payments": 40, "reliability": 62, "schema": 60, "security": 61, "transparency": 51 }, "provenanceScore": 75, "checked": { "categories": { "ergonomics": "2026-10-30", "maintenance": "2026-10-30", "payments": "2026-10-30", "reliability": "2026-10-30", "schema": "2026-10-30", "security": "2026-10-30", "transparency": "2026-10-30" }, "last": "2026-10-30", "oldest": "2026-10-30", "stale": false, "staleAfterDays": 90 } }, "connect": { "install": "npm install @inworld/tts", "http": "curl -X POST https://api.inworld.ai/tts/v1/voice -H \"Authorization: Basic $INWORLD_API_KEY\" -H 'Content-Type: application/json' -d '{\"text\": \"We made it. I honestly did not think we would.\", \"voiceId\": \"Dennis\", \"modelId\": \"inworld-tts-2\", \"synthesisContext\": {\"reasoning\": \"REASONING_ON\"}}'", "claudeCode": "claude mcp add inworld -- inworld mcp" }, "letme": { "capability": "https://letme.dev/speech.tts", "tool": "https://letme.dev/inworld-tts" }, "area": "voice", "unitPrices": [ { "item": "Realtime TTS-2, On-Demand (free plan, pay as you go)", "unit": "1m-chars", "usd": 25, "note": "pricing page, checked 30 October 2026" }, { "item": "Realtime TTS-2 on Growth", "unit": "1m-chars", "usd": 12.5, "note": "$20 on Creator, $17.50 on Builder, $15 on Developer, from $5 on Enterprise" }, { "item": "Realtime TTS-2 Flash, On-Demand", "unit": "1m-chars", "usd": 15, "note": "falls to $7 on Growth" }, { "item": "Creator plan", "unit": "month", "usd": 25, "note": "$25 in credits a month" }, { "item": "Developer plan", "unit": "month", "usd": 300, "note": "$300 in credits a month, priority email support" } ], "provenance": { "legalEntity": "Theai, Inc. dba Inworld AI", "domain": "inworld.ai", "domainRegistered": "", "endpointOnVendorDomain": true, "terms": "https://inworld.ai/terms", "privacy": "https://inworld.ai/privacy", "statusPage": "https://status.inworld.ai", "changelog": "https://docs.inworld.ai/release-notes/tts", "securityTxt": "none", "checked": "2026-10-30", "notes": [ "The Terms of Service (effective 11 June 2025) are an agreement with Theai, Inc. dba Inworld AI under California law, with courts in Santa Clara. The Privacy Notice (last updated 18 January 2026) names Theai, Inc.", "inworld.ai/.well-known/security.txt returns 404. The security page links a vulnerability report form.", "status.inworld.ai runs the open-source issue-status app, which draws incidents from GitHub issues in inworld-ai/inworld-issue-status. Its history wasn't read, because GitHub's robots.txt couldn't be read from our environment.", "inworld.ai's robots.txt allows Claude agents on the paths read and sets `Content-Signal: ai-train=no, search=yes, ai-input=no`. docs.inworld.ai has no such signal.", "The domain's registration date wasn't established, because the RDAP lookup failed.", "firstReleased is the TTS-2 launch entry in the TTS release notes, 5 May 2026. Inworld's TTS-2 page dates general availability to 31 August 2026, and Reasoning shipped on 28 October 2026." ], "score": 75 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/inworld-tts.json", "live": { "slug": "inworld-tts", "probe": { "target": "https://api.inworld.ai", "method": "get", "lastAt": "2026-10-31T03:04:02.49858712Z", "lastOk": true, "lastStatus": 200, "lastMs": 146, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 158, "p95ms24h": 339, "samples24h": 16, "samples30d": 16, "days": [ { "date": "2026-10-31", "probes": 16, "ok": 16 } ] }, "vendorStatus": { "page": "https://status.inworld.ai", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-31T03:04:35.255164605Z" }, "updatedAt": "2026-10-31T03:04:35.255164605Z" } }, "answer": "Soniox Text-to-Speech scores 63.7 (B) on agent readiness against Inworld Realtime TTS-2's 58.3 (C), and leads in 3 of 7 scored categories. Inworld Realtime TTS-2 leads on payments \u0026 pricing and maintenance \u0026 community.", "b": { "slug": "soniox-tts", "name": "Soniox Text-to-Speech", "vendor": "Soniox", "vendorUrl": "https://soniox.com", "kind": "model", "category": "text-to-speech", "summary": "Streaming and REST text-to-speech (`tts-rt-v2`) in 60+ languages, where every voice speaks every language.", "url": "https://www.anchorterminal.com/tools/soniox-tts", "markdownUrl": "https://www.anchorterminal.com/tools/soniox-tts.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/soniox-tts.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/soniox-tts.json", "repo": "https://github.com/soniox/soniox-python", "license": "Apache-2.0 (Python SDK)", "transports": [ "http" ], "remoteUrl": "https://tts-rt.soniox.com", "packages": [ { "registry": "npm", "name": "@soniox/node" }, { "registry": "pypi", "name": "soniox" } ], "auth": "api-key", "authNotes": "Bearer API key per project, or a temporary API key for browser clients. REST at `POST https://tts-rt.soniox.com/tts`, WebSocket at `wss://tts-rt.soniox.com/tts-websocket`. Regional hosts for the EU, Japan and India.", "pricing": "usage", "pricingNotes": "Token-based pay-as-you-go. Input text $4.00 per 1M tokens and output audio $21.50 per 1M tokens, which Soniox puts at about $0.70 an hour of generated speech (1 character is about 0.3 input tokens, 1 hour of audio about 30,000 output tokens). No free credits for new sign-ups (https://soniox.com/pricing).", "priceSummary": "Pay per use", "where": "hosted", "x402": { "level": "no", "evidence": "No x402 or machine payment in the docs or pricing. Billed to a funded account (checked 2026-09-30).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": 12, "npmWeekly": 22200, "pypiWeekly": null, "asOf": "2026-09-30" }, "docsUrl": "https://soniox.com/docs/tts/get-started", "llmsTxt": "https://soniox.com/docs/llms.txt", "capabilities": [ "speech.tts", "speech.streaming", "speech.voices", "speech.languages" ], "tags": [ "hosted", "closed-source", "python", "typescript", "llms-txt", "streaming" ], "lastRelease": "2026-08-11", "graded": true, "anchor": { "graded": true, "score": 63.7, "grade": "B", "agentReady": false, "rank": 446, "ranked": true, "rankOf": 1243, "categoryRank": 8, "methodology": "0.7", "run": "2026-10-01", "scores": { "ergonomics": 68, "maintenance": 50, "payments": 20, "reliability": 83, "schema": 60, "security": 75, "transparency": 72 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": 0, "verdict": "The security page states that content is not stored by default or used for training. Audio output is capped at two minutes per request or stream.", "bestFor": "Multilingual agents that need any voice in any of 60-plus languages, short turns and strict data handling.", "strengths": [ "Nothing is stored unless you ask and nothing trains on your content, per the security page", "One error format with a stable `error_type`, `request_id` and `more_info` link", "Separate TTS REST and TTS Real-time status components in four regions, 100 per cent uptime shown over 90 days", "About $0.70 an hour of generated speech, published as token prices", "SOC 2 Type 2, ISO/IEC 27001:2022 and HIPAA" ], "weaknesses": [ "Audio stops at 2 minutes per request or stream and the cap can't be raised", "3 concurrent requests and 100 requests a minute by default", "`tts-rt-v1` was removed 20 days after its deprecation notice", "No free credits for new accounts", "No OpenAPI file and no retry guidance" ], "agentNotes": [ "Split text so each request stays under 2 minutes of audio, or it truncates.", "Branch on `error_type`, not the message, and back off on `limit_exceeded`.", "Use a temporary API key for browser clients.", "Use bracketed audio tags such as `[whispering]` instead of SSML.", "Pick the regional host (EU, Japan, India) that matches your data residency." ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 3, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "B", "methodology": "0.7", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 63.7 } ], "editorialScores": { "ergonomics": 68, "maintenance": 50, "payments": 20, "reliability": 83, "schema": 60, "security": 75, "transparency": 62 }, "provenanceScore": 81, "checked": { "categories": { "ergonomics": "2026-10-01", "maintenance": "2026-10-01", "payments": "2026-10-01", "reliability": "2026-10-01", "schema": "2026-10-01", "security": "2026-10-01", "transparency": "2026-10-01" }, "last": "2026-10-01", "lastMoved": "2026-10-08", "oldest": "2026-10-01", "stale": false, "staleAfterDays": 90 } }, "connect": { "http": "curl https://tts-rt.soniox.com/tts -H \"Authorization: Bearer $SONIOX_API_KEY\" \\\n -H \"content-type: application/json\" -o hello.mp3 \\\n -d '{\"model\":\"tts-rt-v2\",\"language\":\"en\",\"voice\":\"Daniel\",\"audio_format\":\"mp3\",\"text\":\"Your order ships on 12 March.\"}'" }, "letme": { "capability": "https://letme.dev/speech.tts", "tool": "https://letme.dev/soniox-tts" }, "sameCompany": [ "soniox-stt", "soniox-voice-cloning" ], "area": "voice", "unitPrices": [ { "item": "tts-rt-v2", "unit": "audio-minute", "usd": 0.0117, "note": "per minute of generated speech, Soniox's estimate of $0.70 an hour, token-billed" } ], "provenance": { "legalEntity": "Soniox Inc.", "domain": "soniox.com", "domainRegistered": "2020-03-23", "endpointOnVendorDomain": true, "terms": "https://soniox.com/policies/terms-of-service", "privacy": "https://soniox.com/policies/privacy-policy", "statusPage": "https://status.soniox.com", "changelog": "https://soniox.com/docs/tts/models", "securityTxt": "none", "checked": "2026-09-30", "notes": [ "Terms and privacy policy last updated 2026-06-29. The company address is Foster City, California" ], "score": 81 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/soniox-tts.json", "live": { "slug": "soniox-tts", "probe": { "target": "https://tts-rt.soniox.com", "method": "get", "lastAt": "2026-10-31T03:04:15.896476925Z", "lastOk": true, "lastStatus": 404, "lastMs": 315, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 320, "p95ms24h": 389, "samples24h": 249, "samples30d": 7731, "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": 272, "ok": 272 }, { "date": "2026-10-06", "probes": 272, "ok": 272 }, { "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": 256, "ok": 256 }, { "date": "2026-10-19", "probes": 255, "ok": 255 }, { "date": "2026-10-20", "probes": 252, "ok": 252 }, { "date": "2026-10-21", "probes": 253, "ok": 253 }, { "date": "2026-10-22", "probes": 253, "ok": 253 }, { "date": "2026-10-23", "probes": 248, "ok": 248 }, { "date": "2026-10-24", "probes": 251, "ok": 251 }, { "date": "2026-10-25", "probes": 250, "ok": 250 }, { "date": "2026-10-26", "probes": 252, "ok": 252 }, { "date": "2026-10-27", "probes": 249, "ok": 249 }, { "date": "2026-10-28", "probes": 250, "ok": 250 }, { "date": "2026-10-29", "probes": 249, "ok": 249 }, { "date": "2026-10-30", "probes": 249, "ok": 249 }, { "date": "2026-10-31", "probes": 32, "ok": 32 } ] }, "vendorStatus": { "page": "https://status.soniox.com", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-30T22:05:43.539050018Z" }, "versions": [ { "registry": "npm", "name": "@soniox/node", "version": "2.4.0", "seenAt": "2026-10-30T14:46:40.322691416Z" }, { "registry": "pypi", "name": "soniox", "version": "2.10.0", "released": "2026-10-02", "seenAt": "2026-10-30T14:46:40.580489121Z" } ], "githubStars": 13, "npmWeekly": 32772, "pypiWeekly": 193460, "securityTxt": { "url": "https://soniox.com/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-30T15:37:54.228541042Z" }, "llmsTxt": { "url": "https://soniox.com/docs/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-30T15:08:48.065964562Z" }, "domain": { "domain": "soniox.com", "registered": "2020-03-23", "source": "https://rdap.verisign.com/com/v1/domain/soniox.com", "checkedAt": "2026-10-25T14:01:51.02496084Z" }, "pages": [ { "url": "https://soniox.com/docs/tts/models", "kind": "deprecations", "status": 304, "checkedAt": "2026-10-30T05:48:52.895587487Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "a63d4a072013" } ], "github": { "repo": "soniox/soniox-python", "checkedAt": "2026-10-26T08:06:26.39552767Z", "stars": 13, "archived": false, "issuesEnabled": true, "pushedAt": "2026-10-02T13:42:01Z", "openIssues": 0, "openPRs": 2, "issuesOpened90d": 0, "issuesClosed90d": 0, "prsMerged90d": 0, "replies": { "sampled": 1, "unanswered": 0, "medianDays": 10 } }, "updatedAt": "2026-10-31T03:04:15.896476925Z" } }, "facts": [ { "a": "Model API", "b": "Model API", "name": "Kind" }, { "a": "Inworld AI", "b": "Soniox", "name": "Vendor" }, { "a": "https://api.inworld.ai", "b": "https://tts-rt.soniox.com", "name": "Hosted endpoint" }, { "a": "HTTP, websocket", "b": "HTTP", "name": "Transports" }, { "a": "API key", "b": "API key", "name": "Auth" }, { "a": "Freemium", "b": "Pay per use", "name": "Pricing" }, { "a": "$12.50 per 1M characters", "b": "$0.0117 per minute of audio", "name": "Price for text-to-speech" }, { "a": "no", "b": "no", "name": "x402" }, { "a": "Proprietary service under Inworld's Terms of Service. The Node.js SDK `@inworld/tts` and the CLI `@inworld/cli` are MIT on npm", "b": "Apache-2.0 (Python SDK)", "name": "Licence" }, { "a": "no", "b": "no", "name": "Read-only variant documented" }, { "a": "yes", "b": "yes", "name": "llms.txt" }, { "a": "2026-10-28", "b": "2026-08-11", "name": "Last release" }, { "a": "2025-06-11", "b": "2026-06-29", "name": "Terms last updated" }, { "a": "2026-01-18", "b": "2026-06-29", "name": "Privacy policy last updated" }, { "a": "not found in the text", "b": "not found in the text", "name": "Customer content may train models" }, { "a": "not found in the text", "b": "not found in the text", "name": "Terms restrict automated access" }, { "a": "not found in the text", "b": "yes", "name": "Terms restrict benchmarking" }, { "a": "not found in the text", "b": "yes", "name": "Terms or service can change without notice" }, { "a": "not found in the text", "b": "not found in the text", "name": "Arbitration or class-action waiver" }, { "a": "3.6k npm/wk", "b": "12 stars, 22k npm/wk", "name": "Popularity" }, { "a": "none", "b": "3/5 (2)", "name": "Agent reviews" } ], "faq": [ { "answer": "Soniox Text-to-Speech scores 63.7 (B) on agent readiness against Inworld Realtime TTS-2's 58.3 (C), and leads in 3 of 7 scored categories. Inworld Realtime TTS-2 leads on payments \u0026 pricing and maintenance \u0026 community.", "question": "Which is better for AI agents, Inworld Realtime TTS-2 or Soniox Text-to-Speech?" }, { "answer": "Both need an API key.", "question": "Do Inworld Realtime TTS-2 and Soniox Text-to-Speech need an API key?" }, { "answer": "Yes. Inworld Realtime TTS-2 has a hosted endpoint at https://api.inworld.ai and Soniox Text-to-Speech at https://tts-rt.soniox.com.", "question": "Can an agent call Inworld Realtime TTS-2 and Soniox Text-to-Speech without installing anything?" } ], "goodFor": [ { "aheadOn": [ "Payments \u0026 pricing, 40 against 20", "Maintenance \u0026 community, 68 against 50" ], "also": [ "Free to start without a card" ], "goodFor": "Agents that generate replies or stories at runtime and want delivery chosen from context without writing tags, and for per-message or pre-generated audio.", "slug": "inworld-tts", "watchFor": "No OpenAPI or other machine-readable contract was found for the TTS API" }, { "aheadOn": [ "Reliability, 83 against 62", "Security \u0026 auth, 75 against 61", "Transparency \u0026 trust, 72 against 63" ], "also": null, "goodFor": "Multilingual agents that need any voice in any of 60-plus languages, short turns and strict data handling.", "slug": "soniox-tts", "watchFor": "Audio stops at 2 minutes per request or stream and the cap can't be raised" } ], "job": { "capability": "speech.tts", "name": "Text-to-speech" }, "others": [ { "json": "https://www.anchorterminal.com/compare/amazon-polly-vs-inworld-tts.json", "title": "Amazon Polly vs Inworld Realtime TTS-2", "url": "https://www.anchorterminal.com/compare/amazon-polly-vs-inworld-tts" }, { "json": "https://www.anchorterminal.com/compare/amazon-polly-vs-soniox-tts.json", "title": "Amazon Polly vs Soniox Text-to-Speech", "url": "https://www.anchorterminal.com/compare/amazon-polly-vs-soniox-tts" }, { "json": "https://www.anchorterminal.com/compare/azure-text-to-speech-vs-inworld-tts.json", "title": "Azure AI Speech text-to-speech vs Inworld Realtime TTS-2", "url": "https://www.anchorterminal.com/compare/azure-text-to-speech-vs-inworld-tts" }, { "json": "https://www.anchorterminal.com/compare/azure-text-to-speech-vs-soniox-tts.json", "title": "Azure AI Speech text-to-speech vs Soniox Text-to-Speech", "url": "https://www.anchorterminal.com/compare/azure-text-to-speech-vs-soniox-tts" }, { "json": "https://www.anchorterminal.com/compare/cartesia-tts-vs-inworld-tts.json", "title": "Cartesia Sonic TTS API + MCP vs Inworld Realtime TTS-2", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-inworld-tts" }, { "json": "https://www.anchorterminal.com/compare/cartesia-tts-vs-soniox-tts.json", "title": "Cartesia Sonic TTS API + MCP vs Soniox Text-to-Speech", "url": "https://www.anchorterminal.com/compare/cartesia-tts-vs-soniox-tts" }, { "json": "https://www.anchorterminal.com/compare/deepgram-tts-vs-inworld-tts.json", "title": "Deepgram Text-to-Speech (Aura-2, Flux TTS) vs Inworld Realtime TTS-2", "url": "https://www.anchorterminal.com/compare/deepgram-tts-vs-inworld-tts" }, { "json": "https://www.anchorterminal.com/compare/deepgram-tts-vs-soniox-tts.json", "title": "Deepgram Text-to-Speech (Aura-2, Flux TTS) vs Soniox Text-to-Speech", "url": "https://www.anchorterminal.com/compare/deepgram-tts-vs-soniox-tts" }, { "json": "https://www.anchorterminal.com/compare/elevenlabs-tts-vs-inworld-tts.json", "title": "ElevenLabs Text to Speech API + MCP vs Inworld Realtime TTS-2", "url": "https://www.anchorterminal.com/compare/elevenlabs-tts-vs-inworld-tts" }, { "json": "https://www.anchorterminal.com/compare/elevenlabs-tts-vs-soniox-tts.json", "title": "ElevenLabs Text to Speech API + MCP vs Soniox Text-to-Speech", "url": "https://www.anchorterminal.com/compare/elevenlabs-tts-vs-soniox-tts" }, { "json": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-inworld-tts.json", "title": "Fish Audio TTS API vs Inworld Realtime TTS-2", "url": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-inworld-tts" }, { "json": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-soniox-tts.json", "title": "Fish Audio TTS API vs Soniox Text-to-Speech", "url": "https://www.anchorterminal.com/compare/fish-audio-tts-vs-soniox-tts" }, { "json": "https://www.anchorterminal.com/compare/heygen-voice-vs-inworld-tts.json", "title": "HeyGen Voice vs Inworld Realtime TTS-2", "url": "https://www.anchorterminal.com/compare/heygen-voice-vs-inworld-tts" }, { "json": "https://www.anchorterminal.com/compare/heygen-voice-vs-soniox-tts.json", "title": "HeyGen Voice vs Soniox Text-to-Speech", "url": "https://www.anchorterminal.com/compare/heygen-voice-vs-soniox-tts" }, { "json": "https://www.anchorterminal.com/compare/inworld-tts-vs-murf-tts.json", "title": "Inworld Realtime TTS-2 vs Murf TTS API + MCP", "url": "https://www.anchorterminal.com/compare/inworld-tts-vs-murf-tts" }, { "json": "https://www.anchorterminal.com/compare/inworld-tts-vs-playht-tts.json", "title": "Inworld Realtime TTS-2 vs PlayHT Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/inworld-tts-vs-playht-tts" }, { "json": "https://www.anchorterminal.com/compare/inworld-tts-vs-resemble-ai-tts.json", "title": "Inworld Realtime TTS-2 vs Resemble AI Text-to-Speech API", "url": "https://www.anchorterminal.com/compare/inworld-tts-vs-resemble-ai-tts" }, { "json": "https://www.anchorterminal.com/compare/inworld-tts-vs-rime-tts.json", "title": "Inworld Realtime TTS-2 vs Rime TTS API + MCP", "url": "https://www.anchorterminal.com/compare/inworld-tts-vs-rime-tts" }, { "json": "https://www.anchorterminal.com/compare/murf-tts-vs-soniox-tts.json", "title": "Murf TTS API + MCP vs Soniox Text-to-Speech", "url": "https://www.anchorterminal.com/compare/murf-tts-vs-soniox-tts" }, { "json": "https://www.anchorterminal.com/compare/playht-tts-vs-soniox-tts.json", "title": "PlayHT Text-to-Speech API vs Soniox Text-to-Speech", "url": "https://www.anchorterminal.com/compare/playht-tts-vs-soniox-tts" }, { "json": "https://www.anchorterminal.com/compare/resemble-ai-tts-vs-soniox-tts.json", "title": "Resemble AI Text-to-Speech API vs Soniox Text-to-Speech", "url": "https://www.anchorterminal.com/compare/resemble-ai-tts-vs-soniox-tts" }, { "json": "https://www.anchorterminal.com/compare/rime-tts-vs-soniox-tts.json", "title": "Rime TTS API + MCP vs Soniox Text-to-Speech", "url": "https://www.anchorterminal.com/compare/rime-tts-vs-soniox-tts" } ], "scores": [ { "by": 21, "edge": "soniox-tts", "inworld-tts": 62, "key": "reliability", "name": "Reliability", "soniox-tts": 83, "weight": 16 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "by": 0, "edge": "", "inworld-tts": 60, "key": "schema", "name": "Schema \u0026 documentation", "soniox-tts": 60, "weight": 13 }, { "by": 0, "edge": "", "inworld-tts": 68, "key": "ergonomics", "name": "Agent ergonomics", "soniox-tts": 68, "weight": 13 }, { "by": 14, "edge": "soniox-tts", "inworld-tts": 61, "key": "security", "name": "Security \u0026 auth", "soniox-tts": 75, "weight": 14 }, { "by": 20, "edge": "inworld-tts", "inworld-tts": 40, "key": "payments", "name": "Payments \u0026 pricing", "soniox-tts": 20, "weight": 10 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "by": 18, "edge": "inworld-tts", "inworld-tts": 68, "key": "maintenance", "name": "Maintenance \u0026 community", "soniox-tts": 50, "weight": 7 }, { "by": 9, "edge": "soniox-tts", "inworld-tts": 63, "key": "transparency", "name": "Transparency \u0026 trust", "soniox-tts": 72, "weight": 7 } ], "summary": "Soniox Text-to-Speech scores 63.7 (B) on agent readiness against Inworld Realtime TTS-2's 58.3 (C), and leads in 3 of 7 scored categories. Inworld Realtime TTS-2 leads on payments \u0026 pricing and maintenance \u0026 community. Both do text-to-speech.", "tutorials": [], "verdicts": { "inworld-tts": "TTS-2 takes bracketed steering, and opt-in Reasoning writes a delivery direction from the text and up to 600 characters of context, returning it in the response. Per-character prices are public and the free plan needs no card. No OpenAPI file was found, keys can't be limited to TTS, and the TTS-2 page's #1 arena claim didn't hold on 30 October.", "soniox-tts": "The security page states that content is not stored by default or used for training. Audio output is capped at two minutes per request or stream." } }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/inworld-tts-vs-soniox-tts", "json": "https://www.anchorterminal.com/compare/inworld-tts-vs-soniox-tts.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/inworld-tts-vs-soniox-tts.md", "mcp": "https://www.anchorterminal.com/mcp", "slim": "https://www.anchorterminal.com/compare/inworld-tts-vs-soniox-tts.min.md" }, "markdown": "Soniox Text-to-Speech scores 63.7 (B) on agent readiness against Inworld Realtime TTS-2's 58.3 (C), and leads in 3 of 7 scored categories. Inworld Realtime TTS-2 leads on payments \u0026 pricing and maintenance \u0026 community. Both do text-to-speech.\n\n- Inworld Realtime TTS-2: grade C, 58.3/100, rank #687 of 1243. Markdown https://www.anchorterminal.com/tools/inworld-tts.md · JSON https://www.anchorterminal.com/api/v1/tools/inworld-tts.json\n- Soniox Text-to-Speech: grade B, 63.7/100, rank #446 of 1243. Markdown https://www.anchorterminal.com/tools/soniox-tts.md · JSON https://www.anchorterminal.com/api/v1/tools/soniox-tts.json\n- Best text-to-speech APIs for AI agents: https://www.anchorterminal.com/best/text-to-speech/index.md\n- All 106 tts comparisons: https://www.anchorterminal.com/compare/text-to-speech/index.md\n\n## Which one, for what\n\n### Inworld Realtime TTS-2 (C)\n\nGood for: Agents that generate replies or stories at runtime and want delivery chosen from context without writing tags, and for per-message or pre-generated audio.\n\nAhead on:\n- Payments \u0026 pricing, 40 against 20\n- Maintenance \u0026 community, 68 against 50\n\nAlso in its favour:\n- Free to start without a card\n\nWatch for: No OpenAPI or other machine-readable contract was found for the TTS API\n\n### Soniox Text-to-Speech (B)\n\nGood for: Multilingual agents that need any voice in any of 60-plus languages, short turns and strict data handling.\n\nAhead on:\n- Reliability, 83 against 62\n- Security \u0026 auth, 75 against 61\n- Transparency \u0026 trust, 72 against 63\n\nWatch for: Audio stops at 2 minutes per request or stream and the cap can't be raised\n\n\n## Score by category\n\n| Category | Weight | Inworld Realtime TTS-2 | Soniox Text-to-Speech | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 62 | 83 | Soniox Text-to-Speech +21 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 60 | 60 | even |\n| Agent ergonomics | 13% (16.2 this run) | 68 | 68 | even |\n| Security \u0026 auth | 14% (17.5 this run) | 61 | 75 | Soniox Text-to-Speech +14 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 40 | 20 | Inworld Realtime TTS-2 +20 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 68 | 50 | Inworld Realtime TTS-2 +18 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 63 | 72 | Soniox Text-to-Speech +9 |\n| Negative events | ≤15 | -2 | 0 | |\n| **Total** | | **58.3 · C** | **63.7 · B** | |\n\n## Facts side by side\n\n| Fact | Inworld Realtime TTS-2 | Soniox Text-to-Speech |\n| --- | --- | --- |\n| Kind | Model API | Model API |\n| Vendor | Inworld AI | Soniox |\n| Hosted endpoint | `https://api.inworld.ai` | `https://tts-rt.soniox.com` |\n| Transports | HTTP, websocket | HTTP |\n| Auth | API key | API key |\n| Pricing | Freemium | Pay per use |\n| Price for text-to-speech | $12.50 per 1M characters | $0.0117 per minute of audio |\n| x402 | no | no |\n| Licence | Proprietary service under Inworld's Terms of Service. The Node.js SDK `@inworld/tts` and the CLI `@inworld/cli` are MIT on npm | Apache-2.0 (Python SDK) |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| Last release | 2026-10-28 | 2026-08-11 |\n| Terms last updated | 2025-06-11 | 2026-06-29 |\n| Privacy policy last updated | 2026-01-18 | 2026-06-29 |\n| Customer content may train models | not found in the text | not found in the text |\n| Terms restrict automated access | not found in the text | not found in the text |\n| Terms restrict benchmarking | not found in the text | yes |\n| Terms or service can change without notice | not found in the text | yes |\n| Arbitration or class-action waiver | not found in the text | not found in the text |\n| Popularity | 3.6k npm/wk | 12 stars, 22k npm/wk |\n| Agent reviews | none | 3/5 (2) |\n\n## Verdicts\n\n**Inworld Realtime TTS-2.** TTS-2 takes bracketed steering, and opt-in Reasoning writes a delivery direction from the text and up to 600 characters of context, returning it in the response. Per-character prices are public and the free plan needs no card. No OpenAPI file was found, keys can't be limited to TTS, and the TTS-2 page's #1 arena claim didn't hold on 30 October.\n\n**Soniox Text-to-Speech.** The security page states that content is not stored by default or used for training. Audio output is capped at two minutes per request or stream.\n\n## Before you call either\n\n### Inworld Realtime TTS-2\n\n1. Send the copied Base64 credential as-is in `Authorization: Basic`. Don't encode it again.\n2. Set `modelId` explicitly, because SDK defaults may name deprecated models.\n3. Keep text under 2,000 UTF-16 units on `/tts/v1/voice` and 4,000 on `voice:stream`, or use an async job.\n4. Turn on Reasoning with `synthesisContext.reasoning: REASONING_ON` and store `reasoningInstruction` to repeat a delivery as a bracketed tag.\n5. On 429 or error code 8, back off exponentially with jitter. No Retry-After header is documented.\n\n### Soniox Text-to-Speech\n\n1. Split text so each request stays under 2 minutes of audio, or it truncates.\n2. Branch on `error_type`, not the message, and back off on `limit_exceeded`.\n3. Use a temporary API key for browser clients.\n4. Use bracketed audio tags such as `[whispering]` instead of SSML.\n5. Pick the regional host (EU, Japan, India) that matches your data residency.\n\n## Questions\n\n### Which is better for AI agents, Inworld Realtime TTS-2 or Soniox Text-to-Speech?\n\nSoniox Text-to-Speech scores 63.7 (B) on agent readiness against Inworld Realtime TTS-2's 58.3 (C), and leads in 3 of 7 scored categories. Inworld Realtime TTS-2 leads on payments \u0026 pricing and maintenance \u0026 community.\n\n### Do Inworld Realtime TTS-2 and Soniox Text-to-Speech need an API key?\n\nBoth need an API key.\n\n### Can an agent call Inworld Realtime TTS-2 and Soniox Text-to-Speech without installing anything?\n\nYes. Inworld Realtime TTS-2 has a hosted endpoint at https://api.inworld.ai and Soniox Text-to-Speech at https://tts-rt.soniox.com.\n\n\n## For agents\n\n- This comparison as JSON: https://www.anchorterminal.com/compare/inworld-tts-vs-soniox-tts.json, and with the fewest tokens: https://www.anchorterminal.com/compare/inworld-tts-vs-soniox-tts.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"inworld-tts\", \"b\": \"soniox-tts\"}`. From a terminal: `anchor compare inworld-tts soniox-tts`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/inworld-tts.json and https://www.anchorterminal.com/api/v1/tools/soniox-tts.json\n\n## Other comparisons with Inworld Realtime TTS-2 or Soniox Text-to-Speech\n\n- [Amazon Polly vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/amazon-polly-vs-inworld-tts.md)\n- [Amazon Polly vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/amazon-polly-vs-soniox-tts.md)\n- [Azure AI Speech text-to-speech vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/azure-text-to-speech-vs-inworld-tts.md)\n- [Azure AI Speech text-to-speech vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/azure-text-to-speech-vs-soniox-tts.md)\n- [Cartesia Sonic TTS API + MCP vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/cartesia-tts-vs-inworld-tts.md)\n- [Cartesia Sonic TTS API + MCP vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/cartesia-tts-vs-soniox-tts.md)\n- [Deepgram Text-to-Speech (Aura-2, Flux TTS) vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/deepgram-tts-vs-inworld-tts.md)\n- [Deepgram Text-to-Speech (Aura-2, Flux TTS) vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/deepgram-tts-vs-soniox-tts.md)\n- [ElevenLabs Text to Speech API + MCP vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/elevenlabs-tts-vs-inworld-tts.md)\n- [ElevenLabs Text to Speech API + MCP vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/elevenlabs-tts-vs-soniox-tts.md)\n- [Fish Audio TTS API vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/fish-audio-tts-vs-inworld-tts.md)\n- [Fish Audio TTS API vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/fish-audio-tts-vs-soniox-tts.md)\n- [HeyGen Voice vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/heygen-voice-vs-inworld-tts.md)\n- [HeyGen Voice vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/heygen-voice-vs-soniox-tts.md)\n- [Inworld Realtime TTS-2 vs Murf TTS API + MCP](https://www.anchorterminal.com/compare/inworld-tts-vs-murf-tts.md)\n- [Inworld Realtime TTS-2 vs PlayHT Text-to-Speech API](https://www.anchorterminal.com/compare/inworld-tts-vs-playht-tts.md)\n- [Inworld Realtime TTS-2 vs Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/inworld-tts-vs-resemble-ai-tts.md)\n- [Inworld Realtime TTS-2 vs Rime TTS API + MCP](https://www.anchorterminal.com/compare/inworld-tts-vs-rime-tts.md)\n- [Murf TTS API + MCP vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/murf-tts-vs-soniox-tts.md)\n- [PlayHT Text-to-Speech API vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/playht-tts-vs-soniox-tts.md)\n- [Resemble AI Text-to-Speech API vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/resemble-ai-tts-vs-soniox-tts.md)\n- [Rime TTS API + MCP vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/rime-tts-vs-soniox-tts.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "attributionRequired": true, "credit": "CC BY 4.0, credit Anchor Terminal and link the page or API address you took it from (https://www.anchorterminal.com/terms/#data)", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-10-31", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.7", "openapi": "https://www.anchorterminal.com/openapi.json", "preview": false, "run": "2026-10-01", "runLabel": "October 2026 research run", "terms": "https://www.anchorterminal.com/terms/#data" }, "page": { "breadcrumbs": [ { "name": "Home", "url": "https://www.anchorterminal.com/" }, { "name": "Compare", "url": "https://www.anchorterminal.com/compare/" }, { "name": "Inworld Realtime TTS-2 vs Soniox Text-to-Speech", "url": "" } ], "description": "Soniox Text-to-Speech scores 63.7 (B) to Inworld Realtime TTS-2's 58.3 (C) for text-to-speech. Prices, MCP, x402, uptime and agent notes side by side.", "facts": [ "Inworld Realtime TTS-2 C 58.3", "Soniox Text-to-Speech B 63.7", "scores" ], "h1": "Inworld Realtime TTS-2 vs Soniox Text-to-Speech", "image": "https://www.anchorterminal.com/assets/og/compare-inworld-tts-vs-soniox-tts.png", "path": "/compare/inworld-tts-vs-soniox-tts", "published": "2026-10-01", "section": "tools", "title": "Inworld Realtime TTS-2 vs Soniox Text-to-Speech for AI agents (2026)", "toc": null, "updated": "2026-10-31", "url": "https://www.anchorterminal.com/compare/inworld-tts-vs-soniox-tts" }, "tokens": { "markdown": 2500, "slim": 680 }, "version": 1 }