AssemblyAI vs OpenAI Realtime API

Pick two tools from the same category to compare side-by-side.

	AssemblyAI Speech-to-text and speech understanding API for developers building voice products.	OpenAI Realtime API Speech-to-speech realtime model API for building low-latency voice agents.
Category	voice	voice
Vendor type	commercial	commercial
Pricing	usage	usage
Strengths	+ Accurate batch and realtime streaming speech-to-text models + Speech Understanding API for summaries, topics, and structured insights + Built-in PII redaction, profanity filtering, and content moderation + Usage-based pricing with free credits to start	+ Single model handling speech-to-speech with reasoning and tool calling + Multiple transports including WebRTC, WebSocket, and SIP for telephony + Low-latency persistent sessions for natural turn-taking + Specialized variants for live translation and streaming transcription
Tradeoffs	− Proprietary models with no open-weight or self-hosted option − Focused on transcription and understanding rather than text-to-speech	− Locked to OpenAI models with no provider choice − Closed, cloud-only API − Realtime audio pricing can be costly at scale
Used in stacks	0	0