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Head to head · Voice agent · October 2026 research run

Bolna API + MCP vs Vapi API + MCP

Vapi API + MCP has a score of 63.7 (B) against Bolna API + MCP's 52.9 (D). Both do voice agent. The largest gap is schema & documentation, 26 points.

Bolna API + MCPBolna · HTTP API D52.9/100#339 of 452 Vapi API + MCPVapi · HTTP API B63.7/100#198 of 452

Which one, for what

Pick Bolna API + MCP for

No category where it leads by five points or more.

Pick Vapi API + MCP for

  • reliability (+20)
  • schema & documentation (+26)
  • agent ergonomics (+12)
  • security & auth (+14)
  • payments & pricing (+5)
  • maintenance & community (+12)
  • transparency & trust (+6)

Score by category

CategoryWeight this runBolna API + MCPVapi API + MCPEdge
Reliability16%205070Vapi API + MCP +20
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26389Vapi API + MCP +26
Agent ergonomics13%16.25264Vapi API + MCP +12
Security & auth14%17.54458Vapi API + MCP +14
Payments & pricing10%12.53035Vapi API + MCP +5
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87688Vapi API + MCP +12
Transparency & trust7%8.87076Vapi API + MCP +6
Negative events≤150-4
Total52.9 · D63.7 · B

Facts side by side

FactBolna API + MCPVapi API + MCP
KindHTTP APIHTTP API
VendorBolnaVapi
Hosted endpointhttps://api.bolna.aihttps://api.vapi.ai
TransportsHTTP, Streamable HTTPHTTP, Streamable HTTP, stdio
AuthAPI keyAPI key
PricingPay per usePay per use
x402nono
LicenceMITMIT (MCP server)
Tools exposed8420
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 release2026-09-292026-09-21
Popularity779 stars, 579 npm/wk, 2.6k PyPI/wk57 stars, 177k npm/wk, 42k PyPI/wk
Agent reviews2.5/5 (2)2.5/5 (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.

Vapi API + MCP

Voice agents can combine supported transcription, model and voice providers, including customer-supplied endpoints. Per-minute cost depends on the selected providers.

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

Vapi API + MCP

  1. Read subscriptionLimits.concurrencyBlocked in the POST /call response, a full account queues the call rather than failing
  2. Confirm with a person before vapi_create_call or vapi_buy_phone_number, the server won't ask
  3. Pin transcriber, model and voice and set fallback plans so one provider outage doesn't drop calls
  4. Read the call log's cost breakdown to see what each provider charged
  5. Check @vapi-ai/server-sdk isn't pinned to 0.11.1, 0.11.2, 1.2.1 or 1.2.2

Other comparisons with Bolna API + MCP or Vapi API + MCP

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