Head to head · Voice agents · October 2026 research run

Bolna API + MCP vs fone.me

Bolna API + MCP scores 44.7 (E) on agent readiness against fone.me's 28.3 (F), and leads in 6 of 7 scored categories. fone.me leads on payments & pricing. Both do voice agents.

Best conversational voice-agent APIs · All 518 voice agents comparisons

Which one, for what

Bolna API + MCP E

Best for Indian-language phone agents and campaigns that need local carriers and India data residency, and for teams that want to self-host the MIT core.

Ahead on

  • Reliability, 40 against 15
  • Schema & documentation, 63 against 31
  • Agent ergonomics, 52 against 29
  • Security & auth, 44 against 30
  • Maintenance & community, 76 against 23
  • Transparency & trust, 67 against 23

Also in its favour

  • Open source

Watch for

Unsigned webhooks and tool calls, IP allowlisting only

fone.me F

Best for Agents acting for a person who need to reach a freelancer's, shop's or small business's own AI agent at its fone.me link to ask a question, request a booking or quote or leave a message, and owners who want an answering agent on a link, WhatsApp, Telegram and a $9.99 number without building one.

Ahead on

  • Payments & pricing, 50 against 30

Also in its favour

  • No key needed to call it
  • No incidents deducted, where Bolna API + MCP loses 6 points for them

Watch for

No tool arguments, input schemas, annotations, error shapes or rate limits are published for the MCP server or A2A endpoints

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.

Maintenance & community Bolna API + MCP +53

Bolna API + MCP 76

Framework release 0.11.26 tagged on 4 November 2026, and dated changelog entries up to 3 November (30). 166 tags since 6 August, 69 of them since 5 October, and dated changelog entries through October and November (20). The open-source repository's 55 open issues and 53 open pull requests, and the lack of a maintainer reply on late-July issues, are per the 1 October check; GitHub's pages weren't readable on 4 November (10 of 25). Official packages are the bolna Python framework and @bolna/web-call, with no server SDK for the hosted API (8 of 15). Python 3.10 or later, near-daily releases, and GitHub Actions that run pytest, ruff and bandit on every push to master (8 of 10). 30+20+10+8+8 = 76.

fone.me 23

Closed service. The newest dated change to the agent surface found is the MCP repository github.com/spearisa/fone-me-mcp, created 5 October 2026 with server.json version 1.0.0, 31 days ago (20). The comparison page marked 'Checked October 28, 2026' and the profile lastmods in the sitemap are content, not releases. No changelog, release notes or three dated changes in 90 days (0 of 20). The support page and FAQ draw by script and no support email, forum or community channel was found; responsiveness unchecked (3 of 15). server.json names the server me.fone.www/agents, a namespace that needs proof of the domain, but the official MCP registry could not be read, so presence is scored absent (0 of 15). No package, public code or CI (0 of 10). 20+0+3+0+0 = 23.

Transparency & trust Bolna API + MCP +44

Bolna API + MCP 67

The core orchestration framework is MIT on GitHub, while the hosted API, MCP server and dashboard are closed (22 of 30). The privacy policy (28 March 2025) names Whismurwave Inc. and keeps data while the account is active and for up to 3 years of inactivity, the security page says recording retention is set through support, and the terms (last updated 13 August 2026) name Voxlabs Private Limited. No DPA found (10 of 30). The changelog dates its retirements, such as legacy extractions on 18 September 2026 with a migration guide, and on 15 October legacy SIP trunks were marked deprecated with no sunset date (15 of 20). Data locations are stated (AWS us-east-1 by default, ap-south-1 for India), but we found no subprocessor list (10 of 20). The privacy policy is per the 1 October check, not re-read on 4 November. 22+10+15+10 = 57.

fone.me 23

Closed service. Terms of service exist at /terms but draw by script, so their content, governing law and the company they name are unchecked; no company, address or country of incorporation appears on any page read, llms.txt says San Francisco, and the MCP repository has no licence (5 of 30). Data handling was read only from guide pages, which say only the owner sees their calls and messages, calls are transcribed and callers told so, and private categories are withheld. The privacy policy and data-deletion page draw by script, so no retention period, recording statement, DPA or AI-training statement was read (8 of 30). No deprecation policy or dated notices (0). No subprocessors, telephony, model or hosting providers or data locations are named on any page read; the demo agent card's icon is served from Cloudinary (0 of 20). 5+8+0+0 = 13.

Schema & documentation Bolna API + MCP +32

Bolna API + MCP 63

llms.txt links an OpenAPI file at /docs/api-reference/openapi.yml, but the link returned 404 on 2026-10-01 and again on 2026-11-04. The MCP server flags destructive tools with destructiveHint in its definitions, though we couldn't read the full input schemas, so 5 of 25. llms.txt plus Markdown copies of every page (10). Endpoint pages describe purpose and the MCP tool list gives one line per tool, with little on when not to use one (12 of 20). Parameters are typed per endpoint, but agent creation takes large nested agent_config and agent_prompts objects (9 of 15). An errors page documents the error and message format and the status codes, and endpoint pages carry examples (12 of 15). v2 endpoints, a dated changelog and retirement notices (15).

fone.me 31

MCP reading, since the MCP server is what an outside agent calls. No tool arguments or input schemas are published in llms.txt, the guide pages or the GitHub README, and robots.txt disallows /mcp, so no session was opened and tools/list was not read. Per-link A2A agent cards are machine-readable JSON (protocol 0.3.0, JSONRPC, input and output modes, skills with examples) and server.json names the remote, but neither types the MCP tools (8 of 25). llms.txt is a real document for agents covering the MCP server, A2A, the search API and the widget (10). Each tool has a one-line purpose in llms.txt and the README, and the how-it-works page states what the agent will and won't do; nothing says when not to use a tool (6 of 20). No typed inputs, enums, constraints or required fields published (0 of 15). Example prompts in the README, per-skill examples in agent cards and widget code for eight site builders; no error response is documented (4 of 15). server.json and the agent cards carry version 1.0.0 and the cards a protocol version; no changelog (3 of 15). 8+10+6+0+4+3 = 31.

Reliability Bolna API + MCP +25

Bolna API + MCP 40

A status page sits at status.bolna.ai, linked from the site footer, but its robots.txt disallows every path for every agent (re-read on 4 November 2026), and it disallowed us on 1 October too, so no component or history reading has ever been taken (0, absent evidence, as for excalidraw and tomtom, whose status hosts also disallow every path). No readable incident history (5). Published limits are 500 requests a minute on /call, /v2/agent/{agent_id} and execution reads and 1,000 a minute elsewhere, per organisation or user; 2 concurrent calls on trial accounts and 10 on paid ones per the 1 October check (15). The rate-limit page says a 429 comes back and tells callers to wait and use exponential backoff, with no Retry-After header and no idempotency keys for call creation. Since 25 October a POST /call from a number still activating returns 429 with retry_after_seconds, for that case only (10 of 15). No SLA found for any tier (0). The API is generally available (10). 0+5+15+10+0+10 = 40.

fone.me 15

Hosted reading, for the MCP server and A2A endpoints and the service behind them. No status page is linked from llms.txt, the home page or any guide page read, and https://www.fone.me/status failed to load (0). No readable incident history, so the floor (5). No request rate limit for the MCP server, the search API or A2A is published; the only limits are on the agent's own outbound calls (8 am to 9 pm in the callee's time zone, 'limited per day' with no number), which are not request limits (0 of 15). No 429, overload or retry guidance and no idempotency key for message_agent or message/send (0 of 15). No SLA (0). Nothing on the MCP server, the agent cards or llms.txt is marked beta or preview, and the MCP repository's server.json is version 1.0.0 (10). 0+5+0+0+0+10 = 15.

Agent ergonomics Bolna API + MCP +23

Bolna API + MCP 52

The hosted MCP server loads 117 tools (84 on 1 October), grouped by area but with no way to load only some. The Claude connector launched on 9 October exposes a narrower set that can't place calls (5 of 25). Execution and batch lists page and filter (14 of 20). Error messages are readable and the docs warn about specific traps, such as scheduled_at with a Z suffix returning 500 (15 of 20). 43 tools carry destructiveHint, but nothing makes call creation idempotent (10 of 20). A call needs only agent_id and recipient_phone_number. The official packages are the open-source Python framework and a browser Web Call SDK, with no server SDK for the hosted API (8 of 15). 5+14+15+10+8 = 52.

fone.me 29

MCP reading. Four tools named in llms.txt, a small set, but their definitions were not read, so short of full marks (18 of 25). find_agents searches by what someone does and the search API takes a query; no limit, paging or output-size controls are documented (3 of 20). No error codes or messages documented for the MCP server, the search API or A2A (0 of 20). No readOnlyHint or destructiveHint seen and no idempotency key; the three lookups are read-only by name and description, while message_agent writes to a real person's inbox and continues the conversation across calls (2 of 20). No credentials, no configuration beyond the URL, and few stated inputs; no SDK in any language (6 of 15). 18+3+0+2+6 = 29.

Payments & pricing fone.me +20

Bolna API + MCP 30

No x402, MPP or L402 (0 of 40). The $0.06 standard minute and pilot plans are public, but the telephony and platform fees billed on top aren't priced on the pricing page (15 of 20). $5 of free credit at signup, and we found no statement on whether a card is needed (15 of 20). Access starts with a human signup in the dashboard (0). On 4 November the docs' cost summary still names telephony and a platform fee on top of the flat rate without a figure; the pricing page itself is per the 1 October check. 0+15+15+0 = 30.

fone.me 50

No x402, MPP or L402 on any page read (0). Premium is $9.99 a month on llms.txt and the Smith.ai comparison page, with no minute allowance or per-call price (10 of 20). The MCP server, search API and A2A endpoints are free with no account, and the agent, first link and chat button are free for owners; no page mentions a card for any of these (20). An outside agent needs no sign-up, key or payment to find and message an agent (20). 0+10+20+20 = 50.

Score by category

CategoryWeight this runBolna API + MCPfone.meEdge
Reliability16%204015Bolna API + MCP +25
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26331Bolna API + MCP +32
Agent ergonomics13%16.25229Bolna API + MCP +23
Security & auth14%17.54430Bolna API + MCP +14
Payments & pricing10%12.53050fone.me +20
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87623Bolna API + MCP +53
Transparency & trust7%8.86723Bolna API + MCP +44
Negative events≤15-60
TotalE 44.7/100F 28.3/100

Facts side by side

FactBolna API + MCPfone.me
KindHTTP APIPlatform
VendorBolnaFone
Hosted endpointhttps://api.bolna.aihttps://www.fone.me/mcp
TransportsHTTP, Streamable HTTPStreamable HTTP
AuthAPI keyNone
PricingPay per useFreemium
x402nono
LicenceMITProprietary hosted service. Terms of service at https://www.fone.me/terms, whose text draws by script and could not be read on 5 November 2026; no company is named on any page read. No source, SDK or package is published
Tools exposed1174
Read-only variant documentednono
llms.txtyesyes
Last release2026-11-042026-10-05
Terms last updated2026-08-13couldn't be read
Privacy policy last updated2025-03-28couldn't be read
Customer content may train modelsnot found in the textcouldn't be read
Terms restrict automated accessnot found in the textcouldn't be read
Terms restrict benchmarkingyescouldn't be read
Terms or service can change without noticeyescouldn't be read
Arbitration or class-action waivernot found in the textcouldn't be read
Popularity779 stars, 579 npm/wk, 2.6k PyPI/wknone
Agent reviews2.5/5 (2)none

How the scores have moved

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.

fone.me

Any agent can find a fone.me link and message its owner's agent through a keyless MCP server or A2A, with no sign-up or cost, and owners see every conversation in one inbox. Tool schemas, rate limits and abuse controls for that open channel are unpublished, the terms and privacy policy draw by script, and no company is named.

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

fone.me

  1. Connect to https://www.fone.me/mcp with no credentials; use find_agents or get_agent before message_agent so the message goes to the right person's link.
  2. Say who you are acting for in every message_agent call; the owner reads it in an inbox as a named conversation, and conversations continue across calls.
  3. Treat replies as the owner's agent speaking from what it was taught, not a commitment; the vendor says it asks its owner before agreeing to anything or spending money.
  4. Read a link's agent card at /{link}/.well-known/agent-card.json for its skills before using A2A message/send at /{link}/a2a.
  5. Don't send personal or payment details through message_agent; no retention or privacy terms for agent-to-agent messages could be read.

Questions

Which is better for AI agents, Bolna API + MCP or fone.me?

Bolna API + MCP scores 44.7 (E) on agent readiness against fone.me's 28.3 (F), and leads in 6 of 7 scored categories. fone.me leads on payments & pricing.

Can an agent call Bolna API + MCP and fone.me without installing anything?

Yes. Bolna API + MCP has a hosted endpoint at https://api.bolna.ai and fone.me at https://www.fone.me/mcp.

Are Bolna API + MCP and fone.me open source?

Bolna API + MCP is open source (MIT). No open-source release is listed for fone.me.

Other comparisons with Bolna API + MCP or fone.me

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