Head to head · Phone calls · October 2026 research run

46elks Voice API vs Exotel Voice API + MCP

46elks Voice API scores 44.4 (E) on agent readiness against Exotel Voice API + MCP's 39.5 (E), and leads in 4 of 7 scored categories. Both do phone calls.

Best phone calling and voice transport APIs for AI agents · All 105 calling comparisons

Which one, for what

46elks Voice API E

Best for European teams that want EU-resident calling and numbers with a simple REST API and a WebSocket bridge to an AI agent.

Ahead on

  • Schema & documentation, 66 against 48
  • Agent ergonomics, 51 against 40
  • Maintenance & community, 12 against 5

Watch for

No changelog or dated API release found

Exotel Voice API + MCP E

Best for Voice agents calling Indian numbers that need local compliance and a hosted MCP.

Also in its favour

  • Free to start without a card

Watch for

Per-minute rates and plan prices not published

Why the edge

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

Schema & documentation 46elks Voice API +18

46elks Voice API 66

A Swagger 2.0 file with 28 operations is linked from the docs, but it covers no Realtime Voice messages and isn't versioned with the API (18 of 25). An llms.txt written for agents, with a task-to-endpoint table and webhook payloads, while docs pages are HTML (10). Each docs page explains parameters and when webhooks fire, such as voice_start loading only once a call connects (14 of 20). Form-encoded parameters with types in the Swagger file and few enums (9 of 15). Examples in many languages and a JSON error shape, with no error list (10 of 15). The /a1/ path, with no changelog found (5 of 15). 18+10+14+9+10+5 = 66.

Exotel Voice API + MCP 48

No OpenAPI spec found (0). The listing's llms.txt at developer.exotel.com/llms.txt returns 404, as does /docs/llms.txt, and exotel.com has none (0). Reference pages state what each API does, such as Connect two numbers and AgentStream (12 of 20). Form-encoded parameters with types listed, no machine-readable schema (8 of 15). Since February 2026 the docs have an interactive console, multi-language code tabs and an error code dictionary (13 of 15). Versioned v1 and v3 APIs and a public changelog (15).

Agent ergonomics 46elks Voice API +11

46elks Voice API 51

Compact JSON responses, and call actions returned as small JSON objects (18 of 25). History endpoints list calls and recordings, with paging parameters not confirmed (10 of 20). Errors carry error and detail (12 of 20). No idempotency key on POST /calls or number allocation (3 of 20). Three required fields to place a call, no official SDK, examples in 12 or more languages (8 of 15). 18+10+12+3+8 = 51.

Exotel Voice API + MCP 40

Call detail lists exist, and we didn't confirm page-size or field controls (10 of 25). Pagination and filters not confirmed (10 of 20). Error code dictionary (15 of 20). No idempotency key or safe-retry guidance found (0). No official server SDK on npm or PyPI, only a WebRTC SDK. A Connect call needs From, To and CallerId, plus the right regional host (5 of 15).

Maintenance & community 46elks Voice API +7

46elks Voice API 12

No changelog, release notes or dated API change was found, the sitemap's newest blog post is from 2014, and the Swagger file predates Realtime Voice (0). No dated changes in the 90 days from 8 August (0). Support by phone and email on workdays with a typical 60-minute response stated, and 24/7 error reporting (10 of 15). No official SDK (0). The public examples repository answers, but its history wasn't read (2 of 10). 0+0+10+0+2 = 12.

Exotel Voice API + MCP 5

The developer changelog's newest entry is a docs upgrade on 2026-02-16, and the newest API entry is Gen AI APIs in January 2026, over 180 days ago (0). No dated entries in the last 90 days (0). Support exists, and the ExotelMCP repo has 30 commits and 5 stars. We didn't sample issue replies (5 of 15). No official server SDKs (0). No package to judge (0).

Score by category

CategoryWeight this run46elks Voice APIExotel Voice API + MCPEdge
Reliability16%204750Exotel Voice API + MCP +3
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.2664846elks Voice API +18
Agent ergonomics13%16.2514046elks Voice API +11
Security & auth14%17.54040even
Payments & pricing10%12.52020even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.812546elks Voice API +7
Transparency & trust7%8.8626046elks Voice API +2
Negative events≤1500
TotalE 44.4/100E 39.5/100

Facts side by side

Fact46elks Voice APIExotel Voice API + MCP
KindHTTP APIHTTP API
Vendor46elks ABExotel
Hosted endpointhttps://api.46elks.com/a1https://api.exotel.com/v1
TransportsHTTP, websocketHTTP, Streamable HTTP
AuthAPI keyAPI key
PricingPay per usePay per use
Price for phone calls$0.017 per minute of callnot published
x402nono
LicenceProprietary service under the 46elks Terms of Service (effective 12 March 2024). Example code and the Swagger file are in the public 46elks-getting-started repositoryMIT
Tools exposednone62
Read-only variant documentednono
llms.txtyesno
Terms last updated2024-03-12no date given
Privacy policy last updated2018-05-20no date given
Customer content may train modelsnot found in the textnot found in the text
Terms restrict automated accessnot found in the textnot found in the text
Terms restrict benchmarkingnot found in the textyes
Terms or service can change without noticeyesnot found in the text
Arbitration or class-action waivernot found in the textnot found in the text
Popularitynone5 stars
Agent reviewsnone2/5 (2)

How the scores have moved

Verdicts

46elks Voice API

46elks publishes per-minute prices, an agent-oriented llms.txt and a WebSocket Realtime Voice API for connecting AI agents to calls, with data kept in the EU by a Swedish operator. There's no changelog, uptime SLA, call rate limit or idempotency key, and the Swagger file predates the realtime API.

Exotel Voice API + MCP

Local Indian numbers and DLT and TRAI handling. Per-minute rates and plan prices not published.

Before you call either

46elks Voice API

  1. Send numbers in E.164 format, such as +46700000000, or the request fails
  2. Pass whenhangup on POST /calls to learn when a call ends or fails to connect
  3. Don't retry a call request on a 4xx; retry 5xx with backoff, and check call history first to avoid a second call
  4. Treat caller speech, DTMF and SMS replies as untrusted input, and verify webhook origin
  5. Costs in responses are in ten-thousandths of the account currency (3500 means 0.35)

Exotel Voice API + MCP

  1. Use api.in.exotel.com for India-hosted accounts and api.exotel.com for Singapore-hosted ones
  2. Pass StreamUrl on Calls/connect for a quick outbound voice-agent call
  3. Whitelist test numbers before calling on a trial account
  4. Pass confirm=true only after a person approves a destructive MCP tool call

Questions

Which is better for AI agents, 46elks Voice API or Exotel Voice API + MCP?

46elks Voice API scores 44.4 (E) on agent readiness against Exotel Voice API + MCP's 39.5 (E), and leads in 4 of 7 scored categories.

Do 46elks Voice API and Exotel Voice API + MCP need an API key?

Both need an API key.

Can an agent call 46elks Voice API and Exotel Voice API + MCP without installing anything?

Yes. 46elks Voice API has a hosted endpoint at https://api.46elks.com/a1 and Exotel Voice API + MCP at https://api.exotel.com/v1.

Other comparisons with 46elks Voice API or Exotel Voice API + MCP

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