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Best free AI for voice agents
Options you can use without paying: free, open source or with a free tier, ranked from public benchmarks.
STop ranked: Cartesia Line (Cartesia), 1,034 on Artificial Analysis Speech Agent Arena (cascaded agent platforms).7 options listed · data verified 19 Oct 2026
Ranked list
| Tier | Name | Approach | Runs | Rated by | Price | Skill | Compare |
|---|---|---|---|---|---|---|---|
| S |  Cartesia LineCartesia | Voice-agent platforms | Cloud | 1,034 on Artificial Analysis Speech Agent Arena (cascaded agent platforms) | Free tier · $5/mo | intermediate | |
| S |  ElevenLabsElevenLabs | Voice-agent platforms | Cloud | 998 on Artificial Analysis Speech Agent Arena (cascaded agent platforms) | Free tier · $6/mo | beginner | vs Cartesia Line |
| S |  GeminiGoogle | Apps | Cloud | via Gemini 3.8 Live | Free tier · $4.99/mo | beginner | |
| S |  GrokSpaceXSI (formerly xAI) | Apps | Cloud | via Grok Voice 3.0 | Free tier · $8/mo | beginner | |
| A |  ChatGPTOpenAI | Apps | Cloud | via GPT-Live 1 | Free tier · $20/mo | beginner | |
| B |  Deepgram Voice Agent APIDeepgram | Voice-agent platforms | Cloud | 916 on Artificial Analysis Speech Agent Arena (cascaded agent platforms) | Free tier | intermediate | vs Cartesia Line |
| B |  Retell AIRetell AI | Voice-agent platforms | Cloud | via GPT-Realtime-2.1 | Free tier | intermediate |
Tiers come only from public benchmarks (Artificial Analysis Speech Agent Arena (cascaded agent platforms)); tools without a result of their own inherit the tier of the best model they offer. How we rank.