Vapi
By Vapi
Developer platform for building production voice agents — pick your own LLM, TTS provider, and telephony, with sub-second latency and full API control.
Best for
- custom phone agents
- voice AI prototyping
- low-latency conversational apps
- BYO model voice infrastructure
Other Voice & audio
ElevenLabs
Best-in-class voice cloning and text-to-speech, with an API used by audiobook publishers and game studios.
Otter.ai
Live meeting transcription with speaker labels and AI-generated summaries; integrates with Zoom, Meet, Teams.
Fathom
Free meeting recorder for sales and CS teams; produces structured notes and pushes them into your CRM.
Granola
Mac-native meeting note-taker that augments your own notes with AI rather than replacing them.
Deepgram
Speech-to-text and text-to-speech API known for the fastest real-time transcription, WebSocket streaming, and accuracy across accents in 30+ languages.
AssemblyAI
Speech-to-text API plus audio intelligence: summarization, sentiment, topic detection, speaker diarization, and LeMUR for LLM-powered audio analysis.
Bland
Voice agent platform optimized for high-volume outbound calling with proprietary voice models — flat pricing, granular conversation control.
Retell
Voice agent platform with strong turn-taking handling, transparent component pricing, and compliance certifications (HIPAA, SOC 2).