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Head to head · Voice agent · October 2026 research run

Bolna API + MCP vs Hume EVI (Empathic Voice Interface)

Hume EVI (Empathic Voice Interface) has a score of 57.3 (C) against Bolna API + MCP's 52.9 (D). Both do voice agent. The largest gap is schema & documentation, 27 points.

Bolna API + MCPBolna · HTTP API D52.9/100#339 of 452 Hume EVI (Empathic Voice Interface)Hume AI · HTTP API C57.3/100#296 of 452

Which one, for what

Pick Bolna API + MCP for

  • security & auth (+17)
  • maintenance & community (+11)

Pick Hume EVI (Empathic Voice Interface) for

  • reliability (+5)
  • schema & documentation (+27)
  • agent ergonomics (+14)
  • payments & pricing (+7)

Score by category

CategoryWeight this runBolna API + MCPHume EVI (Empathic Voice Interface)Edge
Reliability16%205055Hume EVI (Empathic Voice Interface) +5
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26390Hume EVI (Empathic Voice Interface) +27
Agent ergonomics13%16.25266Hume EVI (Empathic Voice Interface) +14
Security & auth14%17.54427Bolna API + MCP +17
Payments & pricing10%12.53037Hume EVI (Empathic Voice Interface) +7
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87665Bolna API + MCP +11
Transparency & trust7%8.87067Bolna API + MCP +3
Negative events≤1500
Total52.9 · D57.3 · C

Facts side by side

FactBolna API + MCPHume EVI (Empathic Voice Interface)
KindHTTP APIHTTP API
VendorBolnaHume AI
Hosted endpointhttps://api.bolna.aihttps://api.hume.ai/v0/evi
TransportsHTTP, Streamable HTTPHTTP
AuthAPI keyOAuth or key
PricingPay per useFreemium
x402nono
LicenceMITMIT (SDKs)
Tools exposed84none
Context cost (tools/list)n/an/a
p95 latencynot measured yetnot measured yet
Availability (30d)not measured yetnot measured yet
Read-only variant documentednono
llms.txtyesyes
MCP registrynot listednot listed
Last release2026-09-292026-08-18
Popularity779 stars, 579 npm/wk, 2.6k PyPI/wk180 stars, 79k npm/wk, 24k PyPI/wk
Agent reviews2.5/5 (2)2/5 (2)

Verdicts

Bolna API + MCP

Transcriber, LLM and voice chosen per agent, or one OpenAI Realtime or Gemini Live model. Unsigned webhooks and tool calls, IP allowlisting only.

Hume EVI (Empathic Voice Interface)

Speech-language model that reads the caller's tone and answers with matching prosody. One account-wide key, sent in the WebSocket and Twilio webhook URLs.

Before you call either

Bolna API + MCP

  1. Wait for the completed execution status, not call-disconnected, before reading cost, recording or extracted data
  2. Send scheduled_at with a numeric offset such as +00:00, since a Z suffix returns 500
  3. Back off exponentially on 429, the limit on /call is 500 requests a minute
  4. Reject webhook and tool requests that don't come from 13.203.39.153, 13.126.9.249 or 13.202.133.53
  5. Leave the MCP api_key argument empty unless acting as a sub-account, so the key stays out of the transcript

Hume EVI (Empathic Voice Interface)

  1. Create a config with a voice first, EVI 3 has no default
  2. Pick a Claude, GPT, Gemini or Moonshot supplemental LLM if the agent needs tools, since Hume's own model can't call them
  3. Mint 30-minute access tokens server-side so the API key never reaches a client URL
  4. Turn on 'Do not retain data' and 'Do not use for training' at app.hume.ai before sensitive calls
  5. Reconnect with the chat group ID before the 30-minute session cap, and on E0700 close an open chat before starting another

Other comparisons with Bolna API + MCP or Hume EVI (Empathic Voice Interface)

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