ToolRankBest voice AI APIs for developers
Updated 16 Oct 2026 · Prices from vendor pages only · How we rank →
The short answer
Each of these is a developer API for speech-to-text, text-to-speech or voice agents. ElevenLabs comes first: top-tier voice quality with a free tier and a cheap Starter plan that adds commercial rights. The cheapest verified paid plan here is ElevenLabs Starter ($6/month). 5 of the 5 have a free plan we could confirm. Every price below is from the vendor’s own page, checked 16 Oct 2026.
Ranked shortlist
- ElevenLabs: Top-tier voice quality with a free tier and a cheap Starter plan that adds commercial rights. Plan: Starter: $6/month
30k credits, commercial license, instant cloning - Deepgram: Speech-to-text and voice agent API. Plan: Not yet verified
- AssemblyAI: Speech-to-text and audio intelligence API. Plan: Not yet verified
- Vapi: Developer platform for voice AI agents. Plan: Core: $29/month
- Inworld AI: Low-cost voice and LLM APIs with pay-as-you-go entry. Plan: Creator: $25/month
TTS-2 $20/1M chars
Tools come from several ToolRank categories, so they are grouped by category and then by each category’s editorial rank. Anything we couldn’t confirm on a vendor page says “Not yet verified”.
Side by side
| Rank | Tool | Relevant plan | Starting price | Free plan | Best for | Main limitation | Last checked |
|---|---|---|---|---|---|---|---|
| #1 | ElevenLabs | Starter: $6/month 30k credits, commercial license, instant cloning | $6/month (Starter) | 10k credits/month, 3 Studio projects, no commercial license | Creators and developers needing realistic voiceovers or voice agents | Free plan (10k credits/month) has no commercial license; cloning and higher quality need paid tiers. | 16 Oct 2026 |
| #2 | Deepgram | Not yet verified | Pay as you go (Nova-3 from about $0.0048/min) | $200 free credit, then pay-as-you-go | Developers adding speech-to-text to apps and voice agents | API only, no end-user app | 16 Oct 2026 |
| #3 | AssemblyAI | Not yet verified | Pay as you go (Universal-2 $0.15/hour) | Free to start, then pay-as-you-go | Developers transcribing recorded audio at scale | API only, no end-user app | 16 Oct 2026 |
| #4 | Vapi | Core: $29/month | $29/month (Core) plus usage | $5 free credits, then pay per minute | Developers building voice agents | Total cost stacks transcriber, model and voice per-minute fees | 16 Oct 2026 |
| #5 | Inworld AI | Creator: $25/month TTS-2 $20/1M chars | $25/month (Creator) | On-Demand: $0 pay as you go, up to 70 min TTS included | Developers building voice-driven games and apps | Developer API product; no consumer app. | 16 Oct 2026 |
Prices as listed by each vendor on the last-checked date, USD, before tax. Plans and limits change, so follow the sources below.
Who should pick which
Pick ElevenLabs for creators and developers needing realistic voiceovers or voice agents (Starter: $6/month); think twice if you need commercial audio for free. Pick Deepgram for developers adding speech-to-text to apps and voice agents (Pay as you go (Nova-3 from about $0.0048/min)). Watch out: API only, no end-user app. Pick AssemblyAI for developers transcribing recorded audio at scale (Pay as you go (Universal-2 $0.15/hour)). Watch out: API only, no end-user app. Pick Vapi for developers building voice agents (Core: $29/month). Watch out: total cost stacks transcriber, model and voice per-minute fees. Pick Inworld AI for developers building voice-driven games and apps (Creator: $25/month); think twice if you want a no-code tool.
FAQ
Which of these is cheapest?
ElevenLabs Starter ($6/month) is the lowest paid price we verified on this list (https://elevenlabs.io/pricing, checked 16 Oct 2026). Check the vendor page for tax, billing period and usage limits.
Which of these have a free plan?
ElevenLabs: 10k credits/month, 3 Studio projects, no commercial license; Deepgram: $200 free credit, then pay-as-you-go; AssemblyAI: Free to start, then pay-as-you-go; Vapi: $5 free credits, then pay per minute; Inworld AI: On-Demand: $0 pay as you go, up to 70 min TTS included.
How were these tools chosen?
They are the tools in ToolRank's rankings with an API product with published pricing, confirmed on the vendor's own website on 16 Oct 2026. Tools we could not verify are left out rather than guessed, and anything unconfirmed is marked Not yet verified.
Sources
- ElevenLabs: ElevenLabs pricing checked 16 Oct 2026
- Deepgram: Deepgram pricing checked 16 Oct 2026
- AssemblyAI: AssemblyAI pricing checked 16 Oct 2026
- Vapi: Vapi pricing checked 16 Oct 2026
- Inworld AI: Inworld pricing checked 16 Oct 2026
Related comparisons
Profiles: ElevenLabs · Deepgram · AssemblyAI · Vapi · Inworld AI
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