FreeTTS
Cloud text-to-speech / AI voice service (freetts.org) offering neural voices across 75+ languages via a small REST/JSON API, plus speech-to-text, AI video and voiceover, audiobook generation, an SRT subtitle surface, and first-party Chrome, Edge and Firefox extensions. Built and operated by Outline Technologies (outline.ad), bootstrapped, founded 2025, hosted on Hetzner in Falkenstein DE behind Cloudflare. The API is a proxy over third-party neural TTS: the live GET /api/voices catalogue probed 2026-08-28 returned 1,410 voices across 152 locales sourced from Google (788), Microsoft Edge (318) and Microsoft Azure (304), of which the 318 Edge voices are the free tier. FreeTTS publishes no OpenAPI, no apis.json, no MCP server and no agent card.
Real signal across most facets with visible, nameable gaps — the contract exists but is thin, or the portal is good while governance and commercial terms are absent.
API Evangelist profiles FreeTTS the way a machine reads it — 6 machine-readable artifacts across 1 API, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — FreeTTS scores 42.6/100 (developing), with a separate agent-readiness read of 8/100 (agent aware). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance. Every facet and dimension name is a link: it opens that measurement's page on APIs.io, where the rating runs across the whole catalog — the exact checks that feed it, how every profiled provider distributes on it, and who is at the top of it.
Kin Score
How this is scored →scored 2026-09-01 · rubric v0.18.0
Put this on your own site. The badge is drawn live from FreeTTS's current Kin Score — paste it once and it updates itself every time the score is recomputed. It follows your visitor's light or dark setting, and it links back here so anyone who sees it can read the full breakdown.
<!-- Kin Score · API Evangelist -->
<a href="https://providers.apievangelist.com/providers/freetts/"
title="FreeTTS on API Evangelist — API profile and Kin Score">
<img src="https://apis.io/badge/freetts.svg"
alt="FreeTTS Kin Score — API readiness rating by API Evangelist" width="150" height="150" loading="lazy">
</a>[](https://providers.apievangelist.com/providers/freetts/)<!-- Kin Score · API Evangelist -->
<a href="https://providers.apievangelist.com/providers/freetts/"
title="FreeTTS on API Evangelist — API profile and Kin Score">
<img src="https://apis.io/badge/freetts/card.svg"
alt="FreeTTS Kin Score — API readiness rating by API Evangelist" width="340" height="120" loading="lazy">
</a>More shapes, themes and sizes → · Score as JSON · How badges work
How we profile FreeTTS
Each block below is one kind of artifact we hold for FreeTTS. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 1
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
FreeTTS REST API
REST/JSON API for text-to-speech synthesis, audio and SRT subtitle download, and voice listing. Uses x-api-key header auth. Endpoints: POST /api/v1/tts, GET /api/audio/{file_id}...
Pricing Plans 1
Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the things the Kin Score reads for access clarity — renamed from commercial clarity in rubric 0.12, because a free statutory interface has access terms and no commercial ones.
Published pricing tiers and plan structures.
Rate Limits 1
Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.
Documented rate limits and quota policies.
Freetts Rate Limits
RATE LIMITSJSON Schema 1
Standalone JSON Schema definitions describe the data models behind the API. We profile them so the shapes are validatable on their own — useful long after a single request is forgotten.
Standalone JSON Schema definitions for this provider's data models.
FreeTTS Voice
JSON SCHEMASecurity Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Resources
Every other property we hold for FreeTTS — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Get Started 2
Portal, sign-up, and the first successful call
Agent Surfaces 1
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 3
Pagination, idempotency, versioning, errors, and events
Build 1
SDKs, sample code, and the tooling you integrate with
Access & Security 1
Authentication, authorization, and security posture
Operate 1
Status, limits, changes, and where to get help
Commercial 4
Pricing, plans, and the legal terms of use
Company 1
The organization behind the API
← All providers · Data indexed from github.com/api-evangelist/freetts · machine-readable index on apis.io
This is an independent, third-party profile of FreeTTS, published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.
The Kin Score and Agent Readiness rating are independently calculated assessments of a company's public API artifacts, scored against a published rubric. They are not certifications, endorsements, security assessments, or audits.
Corrections, re-scores, and removal are free — no partnership or purchase required, and you do not need to justify the request. A removed company is recorded as unrated, never scored zero for having asked. Acknowledgement within one business day; removal within two.
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you will get a person, not a form — we will tell you exactly which public URLs this profile was built from.