Audio APIs — transcription (STT) and synthesis (TTS) — often ship a real free tier or a sizeable one-time credit. The providers below offer free audio/speech access, from a few free hours a month to hundreds of dollars in starting balance.
Check the "catch" on each provider's page: some free speech tiers forbid commercial use or watermark the output.
Top pick — Groq
Lowest-latency inference for open-weight models Details →
26 verified providers
| Provider | Free tier | Rate limits | Gotchas |
|---|---|---|---|
| Google Gemini API (AI Studio) | Gemini 2.5 Flash, 2.5 Flash-Lite, 2.5 Pro (limited), embeddings, TTS models | Per-model; Google no longer publishes the free-tier numbers in its public docs — they are shown only on the AI Studio rate-limit page after sign-in | no cardno phonecommercial OKOpenAI-compatible |
| Groq | Open-weight models (GPT-OSS, Qwen) plus Whisper, no credit card required | Free plan examples: openai/gpt-oss-120b, openai/gpt-oss-20b and qwen/qwen3.8-27b: 30 RPM/1K RPD/8K TPM/200K TPD; Whisper models: 20 RPM/2K RPD/7.2K audio seconds/hour and 28.8K/day; limits vary by model | no cardphone requiredcommercial OKOpenAI-compatible |
| Cloudflare Workers AI | 10,000 Neurons/day, all account plans | 10,000 Neurons/day (free allocation). Per-task request limits: text generation 300 requests/min (models that require Workers Paid: 20 requests/min per model); text embeddings 3,000/min; speech recognition, text-to-image, translation, image-to-text 720/min | no cardno phonecommercial OKOpenAI-compatible |
| HuggingFace | Free CPU Basic + ZeroGPU for Spaces; Inference Providers has no included credit on the Free plan (credits must be purchased) — $2.00/mo is included only on PRO/Team/Enterprise | No RPM/TPM published, only credit amounts | no cardOpenAI-compatible |
| OVHcloud AI Endpoints | Seven models are currently listed as Free: two Qwen3Guard moderation models, Stable Diffusion XL and four NVIDIA Riva TTS voices; access is available anonymously or with an API key tied to a Public Cloud project | Anonymous access: 2 requests/min per IP per model. Authenticated (API key): 400 requests/min per project per model. Exceeding either returns HTTP 429 | no cardOpenAI-compatible |
| Scaleway Generative APIs | 1,000,000 tokens free + 60 min Whisper transcription; billing starts at token 1,000,001 | With a validated payment method: 300 RPM / 200k TPM per model; 600 RPM and higher TPM once identity is verified | no cardOpenAI-compatible |
| Deepgram | $200 free credit on signup (no card, no expiration) — Nova speech-to-text and Aura text-to-speech at pay-as-you-go rates | STT pre-recorded up to 50 concurrent; STT streaming up to 150; TTS REST up to 15; TTS streaming up to 45 | no cardno phonecommercial OK |
| AssemblyAI | $50 free credit on signup (no card) — pre-recorded & streaming speech-to-text, Speech Understanding, and an OpenAI-compatible LLM Gateway (25+ models) | Free tier: 5 parallel transcriptions; streaming 5 new streams/min; global 20k requests / 5 min | no cardno phonecommercial OKOpenAI-compatible |
| Pollinations.ai | Quest Pollen: create an account, complete eligible Quests on the Quests dashboard and claim the rewards; Quest Pollen is spent before paid Pollen on regular (non-paid-only) models. No anonymous/no-key generation — every generation endpoint requires an API key and costs Pollen ($1 ≈ 1 Pollen). Text, image, video, audio, embeddings and 3D models behind one OpenAI-compatible API | No per-request rate limits published for sk_ keys; usage is bounded by the Pollen balance (legacy raw pk_ keys: 1 Pollen per IP per hour) | no cardno phoneOpenAI-compatible |
| Twelve Labs (Marengo Embed) | Free plan: the Marengo 3.5 Embed API (video, audio, image, text and document inputs) and the Pegasus Analyze API at no cost, plus 600 minutes (10 hours) of video indexing in total | Embed video/audio: 3,000 RPD, 25 RPM; embed text/image: 3,000 RPD, 600 RPM | no card |
| Speechmatics | Free plan: $100 credit grant on signup (no payment card) for Speech-to-Text; Text-to-Speech lists the first 1 million characters free | Free: 2 concurrent real-time sessions; Batch API: 10 new jobs/s and 50 job-status requests/s (bounded by the $100 credit) | no card |
| Speechify API | 500K characters/month TTS (hard cap; pauses until next month), catalog voices, streaming and SSML | Free: 3 concurrent requests, 1 request/s sustained (burst 10); hard monthly cap, no top-ups | no cardno phonecommercial OK |
| Hume AI (Octave TTS) | Free tier for Octave TTS and EVI; new accounts start with $20 in credits | Rate set by subscription tier, numbers not published; max 5,000 characters per utterance and 5 generations per request | no cardeval only |
| Unreal Speech | 250,000 characters/month TTS (~6 hours of audio) | No rate limit published in the current V8 API docs (legacy v7 docs listed 2 requests/second on Free). Per-request size: /stream up to 1,000 characters, /speech up to 3,000, /synthesisTasks up to 500,000 | no cardcommercial OK |
| ElevenLabs | 10,000 credits/month shared across Text-to-Speech, Speech-to-Text and more (~10 min TTS/month) | 2 concurrent requests on the Free plan | no cardno phoneeval only |
| Sarvam AI | ₹100 in free credits on signup, usable across any API including chat completion (Sarvam-105B) and speech (STT/TTS); credits never expire | Starter plan: 40 req/min for chat with Sarvam-105B (60 for other default models), STT REST and TTS REST (bulbul:v3: 30 req/min); 20 concurrent STT WebSocket streams; bounded by the ₹100 credit | commercial OKOpenAI-compatible |
| Gladia | €50 in free credits on signup for speech-to-text (~80+ hrs pre-recorded or 60+ hrs real-time at current rates) | 30 real-time and 25 async concurrent requests (Starter pay-as-you-go plan that carries the €50 credit) | no card |
| Rime | Free minutes for every new account (Starter plan): the pricing card says ~800 minutes (~800k characters), while the FAQ and docs say 3,000 | Starter: 20 concurrent TTS generations | no card |
| Cartesia | 20,000 credits/month (~27 min of Sonic TTS or ~1h51 of Ink speech-to-text) | 2 concurrent TTS requests, 8 concurrent STT; 20,000 credits/month | no cardeval only |
| Fish Audio | App Free plan: 8,000 credits/month (~7 min, up to 500 characters per generation). API: the s2.1-pro-free TTS model is $0 through 2026-11-30 under fair-use limits (pay-as-you-go API, no subscription) | API: 5 concurrent requests (Starter tier, <$100 paid); s2.1-pro-free under unpublished fair-use limits. App Free plan: 500 characters per generation, 8,000 credits/month | no cardeval only |
| Camb.ai | Free plan: 5,000 credits one-time (no monthly renewal) across TTS, dubbing, speech and translation tools | Not published by the provider; bounded by the one-time 5,000-credit grant | |
| Rev AI | Free credits equivalent to 5 hours of Reverb ASR (speech-to-text), usable across all Rev AI products | Bounded by the 5-hour credit grant | no card |
| Voicegain | $50 in free credits on signup (no credit card) — speech-to-text | Default for new accounts: 75 API requests/minute and 2,000/hour; 4 concurrent real-time ASR requests; OFF-LINE transcription up to 4 hours of audio per hour (queue of 10 jobs) | no card |
| Smallest.ai (Waves) | $10 in free credits with full access on Pay As You Go — TTS (Lightning v3.1), STT (Pulse) and voice agents; speech-to-speech (Hydra) is beta/request-access | Pay As You Go: 15 concurrent TTS streams, 100 TTS requests/min, 450M chars/month cap; 100 concurrent STT streams; 20 concurrent agent calls (bounded by the $10 credit) | |
| Retell AI | $10 in free trial credits (once per email address) plus 20 concurrent calls included — voice-agent orchestration (STT + LLM + TTS) | 20 concurrent calls per workspace (Pay-As-You-Go default) | no card |
| Typhoon (SCB 10X) | Free to use research showcase API — all Typhoon models at $0 | typhoon-v2.5-30b-a3b-instruct: 5 requests/second, 200 requests/minute; typhoon-ocr: 2 requests/second, 20 requests/minute; typhoon-asr-realtime: 100 requests/minute | no cardno phonecommercial OKOpenAI-compatible |
FAQ
Is there a free speech-to-text API?
Yes — Groq (Whisper), Cloudflare Workers AI and others offer free STT; several dedicated speech providers also grant a sizeable one-time credit.
Which free speech API is best for production?
Check each provider’s rate limits and whether commercial use is allowed — some free speech tiers are evaluation-only or watermark their output.