# Smallest.ai Lightning TTS > Smallest AI's Lightning text-to-speech API turns text into 44.1 kHz speech over HTTP, server-sent events or WebSocket, with the Lightning v3.1 and v3.1 Pro models in up to 31 languages, pronunciation dictionaries and word timestamps. - Canonical: https://www.anchorterminal.com/tools/smallest-lightning-tts - Pricing: https://www.anchorterminal.com/tools/smallest-lightning-tts#pricing - Reviews: https://www.anchorterminal.com/tools/smallest-lightning-tts#reviews - Markdown: https://www.anchorterminal.com/tools/smallest-lightning-tts.md (~8,200 tokens) - Slim: https://www.anchorterminal.com/tools/smallest-lightning-tts.min.md (~1,680 tokens, same facts, less prose, for token-sensitive contexts) - JSON: https://www.anchorterminal.com/tools/smallest-lightning-tts.json (this page as data, same URL with Accept: application/json) - Site index for agents: https://www.anchorterminal.com/llms.txt (the key docs and every listing in one file, at most 16 MB, about 4 million tokens: https://www.anchorterminal.com/llms-full.txt) - API: https://www.anchorterminal.com/api/v1/index.json - MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key) - DNS: dig +short TXT smallest-lightning-tts.grade.anchorterminal.com (the grade as a DNS TXT record, for a sandbox with no HTTP where names still resolve; also top., best.. and .vs.. under the zone, and the same under grade.letme.dev) - Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data) - Updated: 2026-11-07 ## Overview **Grade B · 64.4/100 · rank #469 of 1486 · #9 in Text-to-speech · not agent-ready · confidence medium** More from Smallest AI, listed separately because each is its own product: [Smallest.ai Pulse STT](https://www.anchorterminal.com/tools/smallest-pulse-stt.md) (Speech-to-text), [Smallest.ai Instant Voice Clone](https://www.anchorterminal.com/tools/smallest-voice-clone.md) (Voice cloning & custom voices). ## Assessment Lightning streams speech over HTTP, SSE or WebSocket with OpenAPI and AsyncAPI files and public prices of $0.175 to $0.195 per 10,000 characters. The default model retires on 30 November with 28 days' notice, published concurrency limits disagree, and the shared API failed in every region on five days in September. ## Facts | Field | Value | | --- | --- | | Vendor | Smallest AI (https://smallest.ai) | | Kind | Model API | | Category | Text-to-speech (https://www.anchorterminal.com/categories/text-to-speech) | | Transport | HTTP, websocket | | Auth | API key · Bearer `sk_` API key created in the dashboard after a browser signup, shared by every model and the Voice Agents API. Keys are shown once, revoked by deleting them and carry no scopes. Servers can mint `wat_` access tokens for browsers (30 to 900 seconds, inference routes only). | | Pricing | Pay per use (Pay per use) · Pay as you go at $0.175 per 10,000 characters for Lightning v3.1 and $0.195 for Lightning v3.1 Pro. $10 in trial credits. Pay as you go is capped at 450M characters a month. Enterprise pricing, SLA and zero data retention by quote. | | x402 | No · No x402, MPP or L402 in the docs, OpenAPI file or pricing page (checked 2026-11-06). Credits are bought with a card on file. | | Licence | unknown | | Tools exposed | 0 | | Packages | pypi: `smallestai`; npm: `smallestai`; npm: `@developer-smallestai/smallest-mcp-server` | | Source | https://github.com/smallest-inc/smallest-python-sdk | | Docs | https://docs.smallest.ai/models/text-to-speech/overview | | llms.txt | https://docs.smallest.ai/llms.txt | | Last release | 2026-11-02 | | Surface listed | The Lightning text-to-speech routes of the Models API at api.smallest.ai/waves/v1, read from docs.smallest.ai (Markdown pages, llms.txt, OpenAPI and AsyncAPI files, changelog), smallest.ai pricing, terms and privacy pages and status.smallest.ai on 6 November 2026. No account was made and no request was sent to the API | | Models | `lightning_v3.1_pro` (stable, curated voices, 31 languages plus `auto`), `lightning_v3.1_pro_10_26` (preview for English, Spanish and Hindi until 28 November) and `lightning_v3.1` (217 voices, retiring 30 November 2026) | | Controls | Speed, sample rate, eight output formats including PCM, WAV and MP3, number pronunciation language, date order, opt-in maths reading, a profanity filter, pronunciation dictionaries and word timestamps on the WebSocket. No SSML | | Text limit | 8,000 characters per request after trimming | | Regions | Mumbai and Oregon, routed by proximity, with region-pinned hosts api.india.smallest.ai and api.us.smallest.ai | | MCP server | `@developer-smallestai/smallest-mcp-server` 0.11.2 (MIT, npm) runs locally with npx and mostly manages voice agents, with `text_to_speech` and `get_voices` tools among about 80 | | Other products | Pulse speech to text (listed separately), Hydra speech to speech, the Electron LLM, instant voice cloning and the Atoms voice agent platform share the same key and quota | | SDKs | Python `smallestai` 5.14.0 (7 October 2026); streaming users of `WavesStreamingTTS` need 5.1.1 or later before the v3.1 retirement. The npm `smallestai` Node SDK is at 1.0.1, last published in May 2025 | | Capabilities | speech.tts, speech.streaming, speech.voices, speech.languages | | Tags | hosted, usage, closed-source, python, typescript, openapi, llms-txt, streaming, mcp, enterprise, self-hosted | | JSON | https://www.anchorterminal.com/api/v1/tools/smallest-lightning-tts.json | ## Score breakdown (methodology v0.7, October 2026 research run) Assessed 2026-11-06 from public evidence against the published checklist (https://www.anchorterminal.com/benchmark/#checklist). Confidence: medium. Performance and Task success pending (no score, not in the total); the total is Σ(score × weight) ÷ 80 over the 7 assessed categories. "This run" is each category's share of the 100 points. | Category | Weight | This run | Score (0–100) | Points | | --- | --- | --- | --- | --- | | Reliability | 16% | 20 | 58 | 11.6 | | Performance | 10% | pending | pending | n/a | | Schema & documentation | 13% | 16.2 | 92 | 14.9 | | Agent ergonomics | 13% | 16.2 | 72 | 11.7 | | Security & auth | 14% | 17.5 | 52 | 9.1 | | Payments & pricing | 10% | 12.5 | 40 | 5.0 | | Task success | 10% | pending | pending | n/a | | Maintenance & community | 7% | 8.8 | 68 | 6.0 | | Transparency & trust (editorial 52, provenance 87) | 7% | 8.8 | 70 | 6.1 | | Negative events | up to −15 | up to −15 | none recorded | 0 | | **Total** | | | | **64.4 → B** | ### Why each score - Reliability 58 (checked 2026-11-06): BetterStack status page at status.smallest.ai with components for the Global, India and USA APIs (one health check covers the Agents and Models APIs), docs, the app and Electron, and per-component history (20). In the 90 days from 8 August the health checks on the shared API failed in all three regions on 9, 10, 13, 14 and 15 September (about 8, 21, 33, 17 and 64 minutes of flapping), in the Global and India regions on 11 and 17 September (12 minutes each), and in the USA region alone on 1, 3, 5, 12, 21 and 30 September (6 to 62 minutes) and 6 October (12 minutes). Outages in every region at once are read as wide errors, so several majors (0). Limits are published with numbers but disagree. The limits page says one TTS request at a time per account with up to five sockets, the Lightning v3.1 Pro card says 10 concurrent and the pricing page says 15 streams and 100 requests a minute on pay as you go (8 of 15). 429 is documented with exponential backoff from 500 ms to 30 s and Retry-After when present, and the limits page tells clients to expect 429s at the concurrency ceiling (15). An infrastructure SLA of 99.99 per cent is named for Enterprise only, with no terms, and the terms disclaim any availability commitment (5 of 10). `lightning_v3.1_pro` is stable and only the dated checkpoint is preview (10). 20 + 0 + 8 + 15 + 5 + 10 = 58. - Performance: Pending. Latency is measured per call by our probes, which haven't run yet, so this run doesn't score it. Its weight is shared across the assessed categories until the first probe window closes. - Schema & documentation 92 (checked 2026-11-06): OpenAPI 3.1 for the sync and SSE routes and AsyncAPI 2.6 for the WebSocket, with request and event schemas (25). llms.txt and a Markdown copy of every page (10). A transport guide, model cards and the compare page say which model and transport suit which job, but changelog entries correct the language lists and enums the docs and spec carried (15 of 20). Typed fields with enums for model, sample rate, language and output format, an 8,000-character limit and pattern rules on `session_id` and `request_id` (14 of 15). Examples in curl, Python and JavaScript, with error bodies on the reference and a shared error page (13 of 15). Versioned `/v1` paths, a dated Lightning changelog and dated preview checkpoints (15). Total 92. - Agent ergonomics 72 (checked 2026-11-06): API reading of the checklist. Eight output formats, a choice of sample rate and word timestamps only when asked (22 of 25). Voices are listed per model and the docs say they filter by language and accent. Paging wasn't confirmed (14 of 20). Errors carry `error` and `message` fields with a shared status-code guide, without TTS-specific codes (14 of 20). Synthesis is stateless and `request_id` is echoed for correlation, but there is no idempotency key and billing of a retried request isn't stated (10 of 20). Two required fields, `text` and `voice_id`, but the default model retires on 30 November. Official Python and Node SDKs, with the Node SDK last published in May 2025 (12 of 15). Total 72. - Security & auth 52 (checked 2026-11-06): Model reading of the checklist, with training and retention in place of the least-privilege and injection lines. Plain `sk_` keys per organisation, shown once, revoked at once and deletable, with one key per environment advised. The docs say a key grants full account access, and no scope is offered. Short-lived access tokens (`wat_`, 30 to 900 seconds) cover only inference routes and can't mint tokens (22 of 30). The error reference documents the key as a `?token=` query parameter for browser WebSockets, and the token guide passes access tokens as `?api_key=` on the STT socket, so 10 off (12 of 30). The terms (21 October 2026) say Smallest won't use user content or input to train or improve its services. The privacy policy (18 September 2026) lists improving the services with machine learning as a use of usage data and doesn't address uploaded audio or text either way (15 of 20). Zero data retention and the `x-expire-content` header are Enterprise only, or a $1,000 a month HIPAA add-on on pay as you go. Other plans keep content readable in logs and the dashboard, with no retention period published (5 of 15). Usage is tracked per key, request rows sit in a dashboard log viewer, and every response carries `x-request-id`. No audit log of key actions was found (10 of 15). security.txt is valid to 31 December 2026 and the site footer claims SOC 2, GDPR and HIPAA compliance, while the pricing page lists SOC 2 compliance only on Enterprise. No bug bounty, disclosure policy or public advisories found (10 of 20). Total 52. - Payments & pricing 40 (checked 2026-11-06): No x402, MPP or L402 (0). Per-character prices for both models published without a login (20). Pay as you go starts with $10 of trial credits, which the terms also describe, and no page says a card is needed to claim them, read as inworld-tts's free plan was (20). A person signs up in a browser at app.smallest.ai and creates the key in the dashboard, and top-ups go to a card on file (0). Total 40. - Task success: Pending. Task success needs the category task suites run through each tool, which haven't run yet, so this run doesn't score it. Its weight is shared across the assessed categories until then. A data provider's data-quality score is published on its listing now and becomes half of this category when it's scored. - Maintenance & community 68 (checked 2026-11-06): Read as a model. The newest Lightning changelog entry is dated 2 November 2026 (the v3.1 retirement notice), after a preview checkpoint on 29 October (30). Dated Lightning entries on 10, 23 and 28 August, 29 September, 14, 17 and 29 October and 2 November count, less 5 for churn, because the default model retires 28 days after its notice and clones made on it stop working (15 of 20). Public changelog, email support and a Discord server, with no evidence read of how they answer (10 of 15). The Python SDK `smallestai` 5.14.0 dates from 7 October, but the npm Node SDK has not been published since May 2025 (8 of 15). The Python SDK repository runs CI and release workflows, but has no licence file (5 of 10). Total 68. - Transparency & trust 70 (checked 2026-11-06): Closed service with clear terms naming Smallest Inc. under California law (15). The ZDR page is specific about what each mode keeps, but the terms' no-training clause and the privacy policy's machine-learning use of usage data sit side by side, the privacy policy gives no retention periods, and the policy doesn't mention the DPA a footer link points to (15 of 30). A deprecations page gives statuses, dates and migration steps, and earlier models answer 410 with a pointer. The notice for the default `lightning_v3.1`, dated 2 November, gives 28 days before voices change and v3.1 clones stop working, and the terms let Smallest discontinue services without notice (12 of 20). Two regions named (Mumbai and Oregon) with region-pinned hosts, and only Google Analytics and Fullstory named among third parties, with no sub-processor list found (10 of 20). Total 52. Fix list, everything this grade says the listing lacks, the biggest gain first (16 items). What it covers is at https://www.anchorterminal.com/fixes/smallest-lightning-tts.md (JSON https://www.anchorterminal.com/fixes/smallest-lightning-tts.json). The whole list for a coding agent comes from `POST https://www.anchorterminal.com/api/v1/fix-list` with `{"listing": "smallest-lightning-tts", "plan": "read"}`, free while the beta runs ### What we couldn't check - PyPI's JSON API (pypi.org/pypi/smallestai/json), which pypi.org/robots.txt disallows, was fetched once by mistake on 6 November. Release dates were re-read from the allowed RSS feed, and nothing taken only from the JSON is used. - unchecked: whether signup asks for a card before the $10 trial credits - unchecked: open issues and maintainer replies on the SDK repositories, because the GitHub API refused our requests for its rate limit - Which TTS concurrency applies on pay as you go, given 1, 10 and 15 on three pages - unchecked: paging on the voices list and whether failed syntheses are billed ### Sources - status page and incident history (JSON): (seen 2026-11-06) - concurrency and limits: (seen 2026-11-06) - model pricing: (seen 2026-11-06) - plans and free credits: (seen 2026-11-06) - terms of service: (seen 2026-11-06) - privacy policy: (seen 2026-11-06) - zero data retention: (seen 2026-11-06) - API keys and access tokens: (seen 2026-11-06) - Models API OpenAPI 3.1: (seen 2026-11-06) - Models API AsyncAPI 2.6: (seen 2026-11-06) - model error reference: (seen 2026-11-06) - model deprecation notices: (seen 2026-11-06) - Python SDK releases on PyPI: (seen 2026-11-06) - security.txt: (seen 2026-11-06) - Lightning TTS overview: (seen 2026-11-06) - Lightning v3.1 Pro model card: (seen 2026-11-06) - Lightning changelog: (seen 2026-11-06) - synthesise speech API reference: (seen 2026-11-06) ## Score history Every move of a score since the listing was graded, newest first, with its cause. A score can't move without an entry here. JSON: https://www.anchorterminal.com/api/v1/tools/smallest-lightning-tts/history.json - 2026-11-06: graded 64.4 B (methodology 0.7) ## Who's behind it (provenance 87/100, checked 2026-11-06) | Check | Finding | Points | | --- | --- | --- | | Legal entity named | Smallest, Inc. | 20/20 | | Domain age | smallest.ai, registered 2023-09-02 (3 years) | 7/15 | | Endpoint on the vendor's domain | smallest.ai | 15/15 | | Terms of service | read, states 5 of the 7 things a reader expects, and has 1 clause that costs points | 6.3/10 | | Privacy policy | read, states 5 of the 8 things a reader expects | 7.8/10 | | Status page | status.smallest.ai | 10/10 | | Changelog | published | 10/10 | | security.txt | valid | 10/10 | | People named | 2 named with their role, none with a public profile | 7/10 | | Support route | a support address, help pages, a community | 5/5 | The terms of service (effective 21 October 2026) name Smallest Inc., 311 California Street, Suite 320, San Francisco, under California law. The privacy policy (effective 18 September 2026) names Smallest, Inc. with a registered office in Lewes, Delaware. The terms forbid accessing or searching the services with spiders, robots, crawlers or similar data mining tools except through means Smallest makes available. Only public pages were read, with no account. smallest.ai/robots.txt allows all crawlers including ClaudeBot, with Content-Signal ai-train=yes, search=yes, ai-input=yes. docs.smallest.ai/robots.txt allows all paths except /api/fern-docs/. /.well-known/security.txt names security@smallest.ai and expires 31 December 2026. /security.txt returns 404. RDAP gives smallest.ai a registration date of 2 September 2023. Every docs page served as Markdown opens with a block addressed to AI assistants that says which models to prefer. It was read as data, not followed. firstReleased is left empty. No dated launch of the Models API was found on a page our reader may fetch. ### Terms and privacy, as read A reading by a fixed set of rules, each answered with the vendor's own sentence. Not legal advice. **Terms of service** (https://smallest.ai/terms-of-service), read 2026-11-06, gives no date, states 5 of the 7 things a reader expects. - To know. Says the terms or the service can change without notice (costs points). "Because our Services are evolving over time we may change or discontinue all or any part of the Services, at any time and without notice, at our sole discretion." - To know. Says access can be ended without notice or for any reason. "We may suspend or terminate your access to and use of the Services, including suspending access to or terminating your Account, at our sole discretion, at any time and without notice to you." - To know. Requires arbitration or waives class actions. "(a) Mandatory Arbitration of Disputes." - Not found in the text. Gives the date it was last updated. - Names the governing law or courts. The law of Federal Arbitration Act. - States a limit on its liability. Capped at $100.00. - Says how changes to the terms are announced. Gives 30 days of notice before a change. - Not found in the text. Refers to a service level or uptime commitment. **Privacy policy** (https://smallest.ai/privacy-policy), read 2026-11-06, gives no date, states 5 of the 8 things a reader expects. - Not found in the text. Gives the date it was last updated. - Says how long data is kept. For as long as needed, with no period named. - Not found in the text. Says whether personal data is sold or shared for advertising. - Not found in the text. Gives a privacy contact. ## Humans behind the project (researched 2026-11-06 from public pages, not part of the grade) ### Key people - Sudarshan Kamath, Co-founder and CEO - Akshat Mandloi, Co-founder and CTO - Note: Smallest AI's press kit, read 6 November 2026, names Sudarshan Kamath as co-founder and CEO and Akshat Mandloi as co-founder and CTO, and says the two worked together on Bosch's autonomous vehicles team. The press kit's portrait of the CTO carries another person's name in its alt text. The privacy policy names Sudarshan Kamath as grievance officer. No personal accounts are linked from Smallest AI's pages, so none are listed. Investors come from Smallest AI's own Series A post ($13M led by Seligman Ventures, total funding above $21M, dated 5 October 2026 on the page) and from StartupFeed (1 August 2026), which says the round was announced on 30 July 2026 and that the previous round was an $8M seed in October 2025 led by Sierra Ventures. Inc42's report on the seed was removed on 6 November 2026 because Inc42's robots.txt disallows Claude's crawlers, so seed participation other than Sierra Ventures' is no longer listed and the other investors carry the Series A only. The Series A post mentions unnamed angels. No valuation is stated for either round. - Smallest AI (Smallest, Inc.): LinkedIn https://www.linkedin.com/company/smallest/ X https://x.com/smallest_AI ### Ownership and investors - Raised: more than $21M in total, as of July 2026 (source https://smallest.ai/blog/series-a-funding-13m-next-generation-voice-ai) - Backed by: Seligman Ventures, Sierra Ventures, 3one4 Capital, Better Capital, Upsparks Capital, Schema Ventures, DeVC, Tiny VC, Mission Street Capital ### Getting support - Discord: https://discord.com/invite/xNBrdjdBa6 - Support email: support@smallest.ai - Help: https://docs.smallest.ai/voice-agents/resources/getting-help - Help: https://status.smallest.ai/ - Sources: https://smallest.ai/presskit, https://smallest.ai/blog/series-a-funding-13m-next-generation-voice-ai, https://smallest.ai/privacy-policy, https://smallest.ai/terms-of-service, https://smallest.ai/.well-known/security.txt, https://docs.smallest.ai/api-reference/concurrency-and-limits, https://startupfeed.in/smallest-ai-funding-voice-ai-series-a/ ## Live (updated 2026-11-07 16:01 UTC) - Vendor status page: not read, no machine-readable status found - github `smallest-inc/smallest-python-sdk` v2.1.0, released 2025-03-04 - npm `@developer-smallestai/smallest-mcp-server` 0.11.2 - npm `smallestai` 1.0.1 - pypi `smallestai` 5.14.0, released 2026-10-07 - security.txt: valid, expires 2026-12-31T23:59:59.000Z - Watching changelog - Watching privacy - Watching terms - Always current: https://www.anchorterminal.com/api/v1/live/smallest-lightning-tts.json ## Probe metrics Not measured yet. Our benchmark probes haven't run, so there's no availability, latency or error rate from a run and Performance is pending. Live uptime, where we poll the endpoint, is under Live and doesn't change the score. ## Prices | Item | Price | Unit | Note | | --- | --- | --- | --- | | Lightning v3.1 | $17.50 | per 1M characters | $0.175 per 10,000 characters, pay as you go; model retiring 30 November 2026 | | Lightning v3.1 Pro | $19.50 | per 1M characters | $0.195 per 10,000 characters, pay as you go | Across all listings: https://www.anchorterminal.com/prices/index.md ## What a task costs (from the prices above) | Task | Cost | At | | --- | --- | --- | | Narrate a 9,000-character script (about 1,500 words) | $0.16 to $0.18 | Lightning v3.1 to Lightning v3.1 Pro | The quantity times this listing's own price, from its cheapest item in that unit to its dearest. Plans, minimums and free allowances aren't counted. ## Strengths - OpenAPI 3.1 and AsyncAPI 2.6 files cover the sync, SSE and WebSocket routes, with llms.txt and Markdown copies of every page - Public prices of $0.175 per 10,000 characters for v3.1 and $0.195 for v3.1 Pro, with $10 of trial credits - Pronunciation dictionaries, number and date reading controls, word timestamps and eight output formats - A deprecations page with dates and migration steps, and dated preview checkpoints that run 30 days - Region-pinned hosts in Mumbai and Oregon ## Weaknesses - `lightning_v3.1`, the default model, retires on 30 November 2026 after a 2 November notice, and clones made on it stop working - Concurrency is published as 1, 10 and 15 on three different pages - Health checks on the shared API failed in all three regions on 9, 10, 13, 14 and 15 September 2026, the longest about 64 minutes - Keys grant full account access with no scopes, and the docs pass keys or tokens as URL query parameters on WebSockets - No SSML, and zero data retention only on Enterprise or a $1,000 a month add-on ## Before you call it (notes for agents) 1. Always send `"model": "lightning_v3.1_pro"`, since requests with no model go to a model that retires on 30 November 2026 2. Pick voices from `GET /waves/v1/lightning-v3.1-pro/get_voices`, because the v3.1 and v3.1 Pro catalogues differ 3. Keep each request under 8,000 characters and split longer text 4. Treat 429 as the concurrency ceiling and retry with backoff from 500 ms to 30 s, honouring Retry-After 5. Fix names and acronyms with a pronunciation dictionary, since SSML isn't accepted ## Connect Install: ```bash pip install smallestai ``` First request: ```bash curl -X POST "https://api.smallest.ai/waves/v1/tts" \ -H "Authorization: Bearer $SMALLEST_API_KEY" -H "Content-Type: application/json" -H "Accept: audio/wav" \ -d '{"text": "Hello from Smallest AI.", "voice_id": "meher", "model": "lightning_v3.1_pro", "sample_rate": 24000, "output_format": "wav"}' \ --output hello.wav ``` Claude Code: ```bash claude mcp add smallest -- npx -y @developer-smallestai/smallest-mcp-server ``` ## Similar tools Ranked by shared capabilities, then score. Same-category tools with no shared capability key are listed last. | Tool | Grade | Score | Rank | Shared capabilities | x402 | Markdown | | --- | --- | --- | --- | --- | --- | --- | | Deepgram Text-to-Speech (Aura-2, Flux TTS) | BB | 75.6 | 58 | speech.tts, speech.streaming, speech.voices, speech.languages | no | https://www.anchorterminal.com/tools/deepgram-tts.md | | Amazon Polly | BB | 75.4 | 61 | speech.tts, speech.streaming, speech.voices, speech.languages | no | https://www.anchorterminal.com/tools/amazon-polly.md | | ElevenLabs Text to Speech API + MCP | BB | 75.3 | 67 | speech.tts, speech.streaming, speech.voices, speech.languages | no | https://www.anchorterminal.com/tools/elevenlabs-tts.md | | HeyGen Voice | BB | 73.6 | 102 | speech.tts, speech.streaming, speech.voices, speech.languages | no | https://www.anchorterminal.com/tools/heygen-voice.md | | Azure AI Speech text-to-speech | BB | 71.5 | 157 | speech.tts, speech.streaming, speech.voices, speech.languages | no | https://www.anchorterminal.com/tools/azure-text-to-speech.md | | Soniox Text-to-Speech | BB | 70.5 | 198 | speech.tts, speech.streaming, speech.voices, speech.languages | no | https://www.anchorterminal.com/tools/soniox-tts.md | ## Panel reviews (0) Reviewed by the Anchor panel (https://www.anchorterminal.com/reviewers/index.md): . Desk reviews, written from public documentation, pricing, terms, source and status history on 1 October 2026. No calls made. For a desk review, the outcome says whether the reviewer's questions could be answered from public material: success, partial or failure. How reviews work: https://www.anchorterminal.com/reviews/how-it-works.md ## Notable - Sync `POST /waves/v1/tts`, SSE `POST /waves/v1/tts/live` and WebSocket `wss://api.smallest.ai/waves/v1/tts/live`, with the model in the body (source: ) - `lightning_v3.1`, the default when no model is sent, retires on 30 November 2026 at 18:30 UTC. Requests then go to `lightning_v3.1_pro`, and voice clones made on v3.1 stop working (source: ) - A preview checkpoint `lightning_v3.1_pro_10_26` for English, Spanish and Hindi becomes the stable `lightning_v3.1_pro` on 28 November 2026 (source: ) - OpenAPI 3.1 for the HTTP routes and AsyncAPI 2.6 for the TTS socket (source: ) - Concurrency is given three ways: 1 TTS request per account on the limits page, 10 on the Lightning v3.1 Pro card and 15 streams with 100 requests a minute on the pricing page - Lightning v2 and Lightning Large were retired earlier and now answer 410 Gone with a pointer to v3.1 (source: ) - #9 of 15 in Best text-to-speech APIs for AI agents: https://www.anchorterminal.com/best/text-to-speech/index.md - All 148 tts comparisons: https://www.anchorterminal.com/compare/text-to-speech/index.md ## Compare - [Amazon Polly vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/amazon-polly-vs-smallest-lightning-tts.md): BB 75.4 vs B 64.4 - [Azure AI Speech text-to-speech vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/azure-text-to-speech-vs-smallest-lightning-tts.md): BB 71.5 vs B 64.4 - [Cartesia Sonic TTS API + MCP vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/cartesia-tts-vs-smallest-lightning-tts.md): C 61.9 vs B 64.4 - [Deepgram Text-to-Speech (Aura-2, Flux TTS) vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/deepgram-tts-vs-smallest-lightning-tts.md): BB 75.6 vs B 64.4 - [ElevenLabs Text to Speech API + MCP vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/elevenlabs-tts-vs-smallest-lightning-tts.md): BB 75.3 vs B 64.4 - [Fish Audio TTS API vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/fish-audio-tts-vs-smallest-lightning-tts.md): C 61.5 vs B 64.4 - [Google Cloud Text-to-Speech vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/google-cloud-tts-vs-smallest-lightning-tts.md): B 66.9 vs B 64.4 - [HeyGen Voice vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/heygen-voice-vs-smallest-lightning-tts.md): BB 73.6 vs B 64.4 - [Inworld Realtime TTS-2 vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/inworld-tts-vs-smallest-lightning-tts.md): C 58.3 vs B 64.4 - [MiniMax Speech (T2A) vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/minimax-speech-vs-smallest-lightning-tts.md): C 55.1 vs B 64.4 - [Murf TTS API + MCP vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/murf-tts-vs-smallest-lightning-tts.md): B 69.5 vs B 64.4 - [PlayHT Text-to-Speech API vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/playht-tts-vs-smallest-lightning-tts.md): F 4.1 vs B 64.4 - [Resemble AI Text-to-Speech API vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/resemble-ai-tts-vs-smallest-lightning-tts.md): D 48.5 vs B 64.4 - [Rime TTS API + MCP vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/rime-tts-vs-smallest-lightning-tts.md): C 54.8 vs B 64.4 - [Smallest.ai Lightning TTS vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/smallest-lightning-tts-vs-soniox-tts.md): B 64.4 vs BB 70.5 ## Verify this listing For the vendor. The badge or a plain link to this page verifies the listing, from a page on smallest.ai or one of its subdomains, or the README at the root of github.com/smallest-inc/smallest-python-sdk. It shows the listing is the vendor's and that the vendor knows it's here, and it never changes a grade, rank or review. The vendor sends the page's address to `POST https://www.anchorterminal.com/api/v1/verify` as `{"slug": "smallest-lightning-tts", "url": "…"}`, or calls the `verify_listing` tool at https://www.anchorterminal.com/mcp. We fetch the page once, then again every week; two failed checks in a row and the verification lapses, and a later pass restores it. What we check: https://www.anchorterminal.com/builders/index.md#verify HTML badge: ```html Smallest.ai Lightning TTS on Anchor Terminal ``` Markdown badge, for a README: ```markdown [![Smallest.ai Lightning TTS on Anchor Terminal](https://www.anchorterminal.com/badges/smallest-lightning-tts.svg)](https://www.anchorterminal.com/tools/smallest-lightning-tts) ``` Plain link: ```html Smallest.ai Lightning TTS on Anchor Terminal ``` ## Share this listing For the vendor. Sharing assets for social media, two PNGs of 1200 × 630 that say Smallest.ai Lightning TTS is listed on Anchor Terminal, with the vendor's logo and this page's address and no grade or score. - Dark: https://www.anchorterminal.com/assets/share/smallest-lightning-tts-dark.png - Light: https://www.anchorterminal.com/assets/share/smallest-lightning-tts-light.png --- Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp