Cartesia Sonic-3: 20,000 free TTS credits per month
Source: https://cartesia.ai/pricing
Description
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+ 1 Cartesia's free plan gives every account 20,000 model credits per month — enough for ~20,000 characters of Sonic-3 text-to-speech (1 credit = 1 character on standard TTS). You also get $1 of prepaid agent credits for trying their voice agents stack. Sonic-3 supports 40+ languages with native voices, full emotion controls, laughter, alphanumeric handling, and ultra-low latency (<100 ms) — the same model the paid tiers use. The free plan is personal use only (no commercial rights), voice cloning is locked to Pro and above, and you get 1 agent slot plus Discord support. No credit card required to sign up.
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Note on the published amount: some third-party listings still cite "10,000 characters/month". The current Cartesia pricing page shows the free plan at 20K credits/month, which at the standard 1 credit/character rate equals 20,000 Sonic-3 characters. Verify on the pricing page before assuming a number — Cartesia has tweaked the free quota multiple times in 2025-2026.
Note on the published amount: some third-party listings still cite "10,000 characters/month". The current Cartesia pricing page shows the free plan at 20K credits/month, which at the standard 1 credit/character rate equals 20,000 Sonic-3 characters. Verify on the pricing page before assuming a number — Cartesia has tweaked the free quota multiple times in 2025-2026.
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+ 9 1. Go to cartesia.ai and click "Get started" (top right) — or jump straight to play.cartesia.ai.
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+ 10 2. Sign up with Google, GitHub, or email + password. No credit card, no phone verification.
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+ 11 3. Confirm your email if you used the email/password path.
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+ 12 4. You land in the Playground — try voices in the browser before touching the API.
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+ 13 5. To use the API: open the dashboard → API Keys → Create API Key. Copy and store it (only shown once).
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+ 14 6. Free credits (20K) are credited automatically and reset on the monthly billing cycle anchor (date you signed up).
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7. Make your first call against https://api.cartesia.ai/tts/bytes with model id sonic-3 (or sonic-3.5 for the latest stable snapshot).
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+ 17 Important:
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+ 18 • Free plan is "Personal use" per Cartesia's pricing page. If you ship anything commercial, you must move to Pro ($4-5/mo billed yearly) or higher.
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+ 19 • Voice cloning is NOT available on free — Pro unlocks instant voice cloning (10-second sample), Startup/Scale unlock professional voice cloning.
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+ 20 • Credits do not roll over. Unused free-tier credits are lost at month reset.
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+ 21 • Agent (voice agent) usage is billed separately from TTS credits — the free $1 prepaid agent balance covers ~71 minutes of voice agent calls at $0.014/min, then it's gone until next month.
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+ 27 CapabilityCredit costFree tier monthly cap
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+ 28 Sonic-3 / Sonic-3.5 TTS1 credit / character~20,000 characters (~3,000 words / ~20 minutes of speech at typical pace)
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+ 29 STT (Speech-to-Text)1 credit / secondUp to ~333 minutes of STT — but every second eats from the same 20K pool
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+ 30 Pro Voice Cloning TTS1.5 credits / characterN/A on free (voice cloning gated to Pro+)
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Voice Agent callsSeparate $1 prepaid pool~71 minutes/month at $0.014/min
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+ 33 The 20K credits are a shared pool — TTS and STT consume from the same budget.
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+ 39 All Sonic family models are accessible on the free plan via the API and Playground:
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+ 41 Model IDDescription
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sonic-3Flagship real-time TTS, 40+ languages, emotion + laughter
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sonic-3.5Latest stable snapshot (current: sonic-3.5-2026-05-04) — auto-updated
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sonic-latestBeta channel, latest experimental Sonic snapshot
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sonic-2Previous generation, still supported
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sonic-turboLower-latency variant for voice agents
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Cartesia STT (ink-whisper, etc.)Speech-to-text models, same 1 credit/sec rate
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+ 49 See the official model list: docs.cartesia.ai/build-with-cartesia/tts-models/latest
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+ 55 Cartesia advertises 40+ languages with native voices, covering ~95% of the world. The model card and marketing materials reference around 42 languages in 2026, including:
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+ 57 • English (US, UK, AU, etc.) with strong heteronym handling
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+ 58 • Spanish, French, German, Italian, Portuguese, Dutch, Polish, Czech, Russian, Ukrainian, Greek, Turkish
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+ 59 • Hindi + 8 additional Indian languages (Tamil, Telugu, Bengali, Marathi, Gujarati, Kannada, Malayalam, Punjabi)
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+ 60 • Japanese, Korean, Mandarin Chinese, Cantonese, Vietnamese, Thai, Indonesian, Malay, Filipino
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+ 61 • Arabic, Hebrew, Persian/Farsi
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+ 62 • Swahili and other African coverage
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+ 64 All languages are available on the free tier — no language gating by plan.
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+ 70 TierPrice (yearly)Model credits/moAgent prepaidVoice cloningCommercial use
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+ 71 Free$020,000$1NoPersonal only
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+ 72 Pro$4-5/mo100,000$5Instant (10-sec sample)Yes
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+ 73 Startup$39/mo1,250,000$49Pro voice cloningYes
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+ 74 Scale$239/mo8,000,000$299Pro voice cloningYes, priority support
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+ 75 EnterpriseCustomCustomCustomCustom + SLAsYes
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+ 77 Monthly billing is roughly 20-25% more expensive than the yearly figures above.
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+ 83 • "Personal use" clause — the free tier is explicitly not for commercial deployment. Cartesia can ban projects shipping production traffic on free credits.
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+ 84 • Voice cloning is the most common upgrade trigger — if you need a custom voice, you need Pro minimum.
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• Quota visible in dashboard — there's no public hard cap warning at 90% usage; monitor your dashboard or your 429s.
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+ 86 • Credits reset, not accumulate — heavy testing in the last week of the month is wasted budget.
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+ 87 • Watermarking: none currently disclosed for Cartesia's TTS output (unlike e.g. Suno or some image models).
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+ 88 • Region: API is globally available; no geo-locks on signup.
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+ 89 • Vapi promo (verified active recently): Vapi sometimes runs "free Sonic-3 on Vapi" weeks where Cartesia credits are zero-rated through the Vapi platform — useful if you want a voice-agent stack without burning either provider's budget. Check vapi.ai/blog/Cartesia-free-sonic-3-TTS for current promos.
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+ 95 • ElevenLabs free tier — 10K characters/month but with voice cloning included on Starter (paid).
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+ 96 • Azure Speech (free tier) — 500K neural TTS characters/month always-free, no cloning, lower-quality voices.
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+ 97 • Google Cloud TTS — 1M Standard / 1M WaveNet characters/month always-free during 12-month trial, then paid.
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• OpenAI TTS — no free tier, but $0.015/1K chars on gpt-4o-mini-tts is cheap enough that 20K chars = $0.30.
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+ 100 For pure character volume on a budget, Azure dominates. For voice quality + emotion + low latency, Cartesia Sonic-3 is hard to beat at $0.
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+ 104 Sources:
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+ 105 • Cartesia Pricing
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+ 106 • Cartesia Sonic-3 product page
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+ 107 • Cartesia TTS models docs
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+ 108 • eesel AI – Cartesia Sonic 3 pricing breakdown (2026)
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+ 109 • Vapi blog – Free Cartesia Sonic-3 on Vapi
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+ 110 • Smallest.ai – Cartesia AI Review 2026
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