Deepgram Voice Agent API vs ElevenLabs Agents API + MCP

Deepgram Voice Agent API

$0.075 a minute all in on Standard, $0.050 with your own LLM and TTS, $200 of credit with no card. No phone numbers or SIP, so you bridge Twilio or another carrier yourself.

ElevenLabs Agents API + MCP

API keys scoped to endpoint groups, with per-key credit limits and service accounts. $0.08 a minute excludes LLM tokens and carrier minutes.

Deepgram Voice Agent API

1. Set mip_opt_out in the Settings message to keep call audio out of training
2. Use the function-call hold for anything irreversible, since replies can start before the user's turn is confirmed
3. Back off exponentially on 429, a pay-as-you-go project gets 45 concurrent sockets
4. Pin the LLM version, an unpinned Gemini route failed for 1.5 hours on 21 July 2026
5. Mint browser tokens with ttl_seconds, not ttl, or they expire after 30 seconds

ElevenLabs Agents API + MCP

1. Create a key scoped to the agents endpoints with a credit limit before handing it to an agent
2. Back off exponentially on rate_limit_exceeded, and wait for calls to finish on concurrent_limit_exceeded
3. Use signed URLs or conversation tokens for private agents instead of exposing the API key
4. Set platform_settings.privacy.retention_days where you don't need 2 years of history
5. Pick a low-latency LLM, the pipeline waits on it every turn