# Audra FAQ > https://audratalks.com/faq — frequently asked questions about the Audra TTS API. ## What's under audra-core? Audra Core — our production speech stack: audra-core inference, plus chunking, −16 LUFS mastering, QA gate, and billing. See /docs/engine. ## Why pay if the weights are open source? You pay for uptime, a production API, long-form chunking, loudness mastering, automated QA, and zero GPU ops — not the model weights. ## Is it OpenAI compatible? Yes. Change your client to POST /v2/speech with model audra-core. See the quickstart in /docs. ## Do you support voice cloning? No. Audra provides preset voices only. For cloning or custom brand voices, use ElevenLabs. ## What languages are supported? English is primary. Beta presets also include Japanese, Chinese, and other languages; quality varies by voice. ## What's the max text length? 50,000 characters per synchronous request (413 if exceeded). For longer batch narration, use POST /v2/speech/jobs (up to 500,000 characters) and poll until completed. Optional webhook_url notifies your server when the job finishes. Text above ~8,000 characters on /v2/speech is auto-queued as a background job unless you pass X-Audra-Sync: true. ## How does billing work? Prepaid credits, billed per Unicode character of trimmed input. Credits reserve when a render starts; if the job fails QA (audio shorter than expected or long silence gaps) or errors, credits auto-refund. ## Is there a free tier? Yes — 25,000 characters once on signup, for evaluation. ## Can I use the free tier commercially? No. Commercial use requires a paid credit purchase, which unlocks commercial flag and higher rate limits. Send X-Audra-Commercial-Use: true on production renders after purchasing. ## I lost my API key — can you resend it? We cannot resend the same key. Sign in at /dashboard (Google or email), open /dashboard/keys to create or rotate keys, or use /dashboard/recover for account recovery (revokes all keys and issues one new key via email). ## What's your refund policy? Failed renders (QA gate or server error) auto-refund credits to your balance. Unused prepaid packs: email hello@audratalks.com within 7 days for manual refund review — not automated in Stripe yet. See /refund. ## Do you offer an SLA? Best-effort in v1 — no uptime guarantee. Check /status for current health. ## What is your data retention policy? We do not persist input text or generated audio — only character counts for billing and account metadata. We do not sell your data. See /privacy. ## What are the rate limits? 60 requests/minute on free tier, 120 requests/minute on commercial (paid) accounts. On 429, respect the Retry-After header (seconds). Long-form jobs should use fewer, larger requests (up to 50k chars) instead of many tiny ones. ## How fast is rendering? Is it real-time? Audra is optimized for batch narration, not sub-200ms live agents. On GPU (Modal), ~500 chars often completes in under 15 seconds; ~10k chars in under 2 minutes sync. Long jobs (50k+ chars) should use POST /v2/speech/jobs. Sync HTTP is capped at 50k characters; use background jobs for chapters or when you need webhook delivery. ## How does quality compare to ElevenLabs? Different tradeoff, not a clone. Audra Core presets with −16 LUFS mastering and QA-gated billing — strong for podcasts, YouTube, courses, and audiobook-style narration at $25/1M. ElevenLabs wins on voice cloning, a larger library, and sub-200ms realtime. Try 25k free chars on your scripts. See /vs/elevenlabs. ## What support do you offer? v1 is best-effort — no SLA or phone support. Start at /support and /faq. Email hello@audratalks.com from your account email with request IDs or timestamps. Check /status before escalating. Enterprise teams above 50M chars/month can email for custom pricing and priority handling. ## How long does ElevenLabs migration take? Under 5 minutes if you're already on the OpenAI SDK. See the migration guide at /migrate. ## What audio formats are supported? MP3 (128 kbps, default) and WAV. Set response_format in your request. ## Do you support background batch rendering or webhooks? Yes. POST /v2/speech/jobs queues batch renders up to 500k characters. Poll GET /v2/speech/jobs/{id} until status is completed, then download GET /v2/speech/jobs/{id}/audio. Pass webhook_url for a completion callback. ## Are volume discounts automatic? Not at checkout. Prepaid credit packs are always $25 per million characters. Your /v2/usage response shows an effective rate by monthly volume for planning — tier pricing is not applied to pack purchases yet. ## Can I self-host instead? Yes — audra-core builds on Apache 2.0 licensed components. See /docs/legal/open-source. We win on convenience, QA, and API. ## Do you offer enterprise plans? Email hello@audratalks.com when you exceed 50M characters/month for custom pricing and support. ## Why am I getting HTTP 402? 402 means insufficient credits or commercial use is blocked. Top up at /dashboard/billing. After any paid pack, send header X-Audra-Commercial-Use: true on production renders. Free-trial evaluation renders do not need the header. ## My HTTP client times out on long scripts — what should I do? Set client timeouts to at least 3600 seconds for sync. Text above ~8k characters auto-queues as a background job unless you pass X-Audra-Sync: true. For chapters or batch pipelines, use POST /v2/speech/jobs (up to 500k chars) and poll or pass webhook_url. ## Does SSML work the same as ElevenLabs? Audra supports common SSML on POST /v2/speech — e.g. . Try the playground at /dashboard/playground. Not every ElevenLabs tag maps 1:1; test your script before shipping.