PlayHT Text-to-Speech API vs Smallest.ai Lightning TTS

PlayHT Text-to-Speech API 0

No live surface to call, so every line scores 0.

Smallest.ai Lightning TTS 72

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.

PlayHT Text-to-Speech API 0

No release or changelog entry in the last 90 days or the last year (0). No support channel (0). SDKs abandoned (0). No package health to judge (0).

Smallest.ai Lightning TTS 68

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.

PlayHT Text-to-Speech API 31

What's left is the docs, still served at docs.play.ht with pages last updated on 9 September 2025 and no shutdown notice. The Markdown copy of each reference page embeds an OpenAPI 3.0.3 fragment for its one operation, with typed enums and seven response codes on the streaming endpoint, and an llms.txt indexes the guides and reference pages as Markdown. Both point at https://api.play.ht, which no longer resolves, and describe the API as live. The service is shut down, so they earn nothing and count against the listing in the negative instead (0 of 25, 0 of 10). The getting-started and streaming pages state purpose and limits (8 of 20). Typed request fields with engine names and a 20,000-character streaming cap (10 of 15). Response codes and examples on the reference pages (8 of 15). Versioned /api/v2 path, and docs.play.ht/changelog returns 404 (5 of 15). Total 31. A model reading these pages or the llms.txt would call an API that doesn't exist.

Smallest.ai Lightning TTS 92

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.

PlayHT Text-to-Speech API 0

Retired. On 2026-10-17 api.play.ht and play.ht didn't resolve, so nothing answers a call. Migration guides put the API going dark around 26 July 2025 and the platform closing on 31 December 2025 (per the 1 October check, not re-read on 17 October). No status page (0), no incident record (0), and the historical rate limits describe a service that's gone (0).

Smallest.ai Lightning TTS 58

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.

PlayHT Text-to-Speech API 0

No live surface. Historically a secret key plus a user ID in two headers, with no scopes. Accounts, audio and clones were reportedly deleted at shutdown with no export. Nothing left to score (0).

Smallest.ai Lightning TTS 52

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.

PlayHT Text-to-Speech API 0

Nothing can be bought. No x402 was ever documented (0), no live pricing (0), no free tier (0), no signup (0).

Smallest.ai Lightning TTS 40

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.