# fone.me vs Inworld Realtime API

> Inworld Realtime scores 60.1 (C) to fone.me's 28.3 (F) for voice agents. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/fone-me-vs-inworld-realtime
- Markdown: https://www.anchorterminal.com/compare/fone-me-vs-inworld-realtime.md (~5,800 tokens)
- Site index for agents: https://www.anchorterminal.com/llms.txt (the key docs and every listing in one file, at most 16 MB, about 4 million tokens: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- DNS: dig +short TXT <slug>.grade.anchorterminal.com (the grade as a DNS TXT record, for a sandbox with no HTTP where names still resolve; also top., best.<category>. and <a>.vs.<b>. under the zone, and the same under grade.letme.dev)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-11-07

Inworld Realtime API scores 60.1 (C) 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.

- fone.me: grade F, 28.3/100, rank #1429 of 1510. Markdown https://www.anchorterminal.com/tools/fone-me.md · JSON https://www.anchorterminal.com/api/v1/tools/fone-me.json
- Inworld Realtime API: grade C, 60.1/100, rank #671 of 1510. Markdown https://www.anchorterminal.com/tools/inworld-realtime.md · JSON https://www.anchorterminal.com/api/v1/tools/inworld-realtime.json
- Best conversational voice-agent APIs: https://www.anchorterminal.com/best/voice-agents/index.md
- All 518 voice agents comparisons: https://www.anchorterminal.com/compare/voice-agents/index.md

## Which one, for what

### fone.me (F)

Good 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 40

Also in its favour:
- No key needed to call it
- A hosted endpoint, with nothing to install

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

### Inworld Realtime API (C)

Good for: Teams moving off OpenAI's Realtime API who want a choice of LLM and Inworld voices.

Ahead on:
- Reliability, 62 against 15
- Schema & documentation, 60 against 31
- Agent ergonomics, 68 against 29
- Security & auth, 58 against 30
- Maintenance & community, 71 against 23
- Transparency & trust, 63 against 23

Watch for: No per-minute price. A session's cost depends on STT, LLM tokens and TTS characters, and interrupted segments are still billed


## Why the edge

### Maintenance & community: Inworld Realtime API +48

- 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.
- Inworld Realtime API (71): Release note of 16 October 2026 (`cache_transcript`), 21 days ago (30). Three dated Realtime entries in the 90 days from 8 August, on 14 September, 23 September and 16 October (20). Discord and support@inworld.ai, with no evidence of answers read (8 of 15). Works with OpenAI's Realtime clients and the CLI is current at 1.5.0, but there is no Inworld Realtime SDK (8 of 15). CLI on npm under MIT, CI not read (5 of 10). Total 71.

### Reliability: Inworld Realtime API +47

- 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.
- Inworld Realtime API (62): Hosted reading of the checklist. status.inworld.ai is a public status page (20), with history we couldn't read, as on inworld-tts (5). Concurrent sessions are published per plan, 10 on On-Demand up to 1,000 on Growth (15). The rate limits page gives exponential backoff with jitter and Retry-After on longer windows, and sessions emit `rate_limits.updated`, with nothing on reconnecting a dropped session (12 of 15). An SLA appears only in the Enterprise column, with no terms (0). No preview or beta label on the Realtime API (10). 20 + 5 + 15 + 12 + 0 + 10 = 62.

### Transparency & trust: Inworld Realtime API +40

- 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.
- Inworld Realtime API (63): Closed service with clear terms naming Theai, Inc. dba Inworld AI (15). The ZDR page says what a session keeps and that third-party LLM requests aren't covered, but the terms and privacy notice disagree on training (12 of 30). Release notes flag potentially breaking changes with the clients affected and what to do, without stating a notice period (14 of 20). US headquarters with EU and India residency on Enterprise, and no sub-processor list in the docs, while sessions may route to third-party LLM providers (10 of 20). Total 51.

### Agent ergonomics: Inworld Realtime API +39

- 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.
- Inworld Realtime API (68): Scored as an API. Conversation history defaults to the last 100 items, can be trimmed, and can be cached on Anthropic models, and every `response.done` carries a `usage` block (18 of 25). No lists to page. Output controls are modalities, turn detection settings, optional transcription and `response.speak` (12 of 20). Error events follow OpenAI's `type` and `code` shape, unsupported fields come back as non-fatal `unsupported_field` warnings, and `item_not_found` names the bad parameter (14 of 20). Tools run on the client and a follow-up response starts automatically after a tool result. Nothing covers side effects of a tool call cut off by an interruption (12 of 20). Works with OpenAI Realtime clients after changing the URL and key, with no Inworld Realtime SDK (12 of 15). Total 68.

### Schema & documentation: Inworld Realtime API +29

- 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.
- Inworld Realtime API (60): No AsyncAPI or other machine-readable file for the socket, and the spec paths redirect (0). llms.txt, Markdown twins and a docs MCP server (10). The overview, OpenAI migration guide, `providerData` reference and the billing page's account of how a session is counted say what to use when (16 of 20). The reference lists every client and server event with field types and required marks, as text rather than a schema (12 of 15). JavaScript and Python example projects and an error event with `type`, `code` and `param`, without a list of codes (9 of 15). Dated release notes with affected clients and required actions, but no API version beyond `/v1` (13 of 15). Total 60.

### Security & auth: Inworld Realtime API +28

- fone.me (30): No credential exists for callers. llms.txt gives auth 'none', the README says the server is 'public, like the links themselves', and the two agent cards read declare no security scheme. There is nothing to leak or rotate, but fone.me and an owner can tell callers apart only by the name they give ('Maria via ChatGPT' in the README) and by traffic, and no caller identity or verification is documented (10 of 30). Three of four MCP tools are lookups; message_agent and A2A message/send reach any owner's agent. On the owner's side the vendor says the agent asks before agreeing to anything or spending money, the owner approves what it will say before a call, outbound calls run only 8 am to 9 pm local, pause when reported and stop permanently on request, and the owner can take over any chat. No read-only mode and no confirmation on the caller's side (8 of 20). message_agent returns text generated from what the owner taught the agent, and every agent on the platform reads messages from anyone; the only guidance is the how-it-works statement that the agent keeps relationship status, health, money and address private, with no documented prompt-injection or spam handling for the open channel, and the call-screening page says it does not promise to block calls (4 of 15). Owners see every call and chat with a transcript in one inbox; nothing is logged for the calling agent (8 of 15). /.well-known/security.txt answers with the app shell, and no disclosure policy, bug bounty or certification appears on any page read (0 of 20). 10+8+4+8+0 = 30.
- Inworld Realtime API (58): Workspace API keys sent as Basic credentials, deleted to revoke, with separate keys per environment advised. The CLI mints read-only keys unless `--write` is given, but write toggles cover only the Voice and Router APIs, so no key is limited to one product. Browsers use short-lived tokens minted server side. Session IDs, not secrets, go in the URL (25 of 30). Tools run in the client, so the developer approves side effects, with no approval step in the API (10 of 20). The agent listens to callers and passes their speech to an LLM, and no prompt-injection guidance was found (5 of 15). Usage per key and a Performance page with errors and throttling (8 of 15). SOC 2 Type II and HIPAA claimed and a vulnerability report form, with no security.txt or bug bounty, per the 4 November reading (10 of 20). Total 58. Zero data retention covers session content from the Developer plan up, but not requests routed to third-party LLM providers.

## Score by category

| Category | Weight | fone.me | Inworld Realtime API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 15 | 62 | Inworld Realtime API +47 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 31 | 60 | Inworld Realtime API +29 |
| Agent ergonomics | 13% (16.2 this run) | 29 | 68 | Inworld Realtime API +39 |
| Security & auth | 14% (17.5 this run) | 30 | 58 | Inworld Realtime API +28 |
| Payments & pricing | 10% (12.5 this run) | 50 | 40 | fone.me +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 23 | 71 | Inworld Realtime API +48 |
| Transparency & trust | 7% (8.8 this run) | 23 | 63 | Inworld Realtime API +40 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **28.3 · F** | **60.1 · C** | |

## Facts side by side

| Fact | fone.me | Inworld Realtime API |
| --- | --- | --- |
| Kind | Platform | HTTP API |
| Vendor | Fone | Inworld AI |
| Hosted endpoint | `https://www.fone.me/mcp` | no (local only) |
| Transports | Streamable HTTP | websocket, HTTP |
| Auth | None | API key |
| Pricing | Freemium | Pay per use |
| Price for voice agents | not published | $25 per 1M characters |
| x402 | no | no |
| Licence | Proprietary 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 | none |
| Tools exposed | 4 | 0 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-05 | 2026-10-16 |
| Terms last updated | couldn't be read | 2025-06-11 |
| Privacy policy last updated | couldn't be read | 2026-01-18 |
| Customer content may train models | couldn't be read | not found in the text |
| Terms restrict automated access | couldn't be read | not found in the text |
| Terms restrict benchmarking | couldn't be read | not found in the text |
| Terms or service can change without notice | couldn't be read | not found in the text |
| Arbitration or class-action waiver | couldn't be read | not found in the text |

## Verdicts

**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.

**Inworld Realtime API.** Inworld's Realtime API speaks OpenAI's Realtime protocol over WebSocket or WebRTC, with a choice of LLM, client-side tools and dated release notes. Cost is the sum of STT, LLM and TTS usage with no per-minute price, there is no machine-readable event schema, and status history couldn't be read.

## Before you call either

### 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.

### Inworld Realtime API

1. Set the auto follow-up off if your client sends its own `response.create` after a tool result, or replies double
2. Read `response.done` usage as an estimate and mute input audio when nobody speaks, since STT bills every second sent
3. Use `response.speak` for fixed greetings, which skips the LLM
4. Treat `unsupported_field` errors as warnings and keep the session open
5. Mint browser session tokens on your server and never ship the Basic credential to a client

## Questions

### Which is better for AI agents, fone.me or Inworld Realtime API?

Inworld Realtime API scores 60.1 (C) 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 fone.me and Inworld Realtime API without installing anything?

fone.me has a hosted endpoint at https://www.fone.me/mcp. No hosted endpoint is listed for Inworld Realtime API.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/fone-me-vs-inworld-realtime.json, and with the fewest tokens: https://www.anchorterminal.com/compare/fone-me-vs-inworld-realtime.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "fone-me", "b": "inworld-realtime"}`. From a terminal: `anchor compare fone-me inworld-realtime`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/fone-me.json and https://www.anchorterminal.com/api/v1/tools/inworld-realtime.json

## Other comparisons with fone.me or Inworld Realtime API

- [Amazon Nova 2 Sonic vs fone.me](https://www.anchorterminal.com/compare/amazon-nova-sonic-vs-fone-me.md)
- [Amazon Nova 2 Sonic vs Inworld Realtime API](https://www.anchorterminal.com/compare/amazon-nova-sonic-vs-inworld-realtime.md)
- [AssemblyAI Voice Agent API vs fone.me](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-fone-me.md)
- [AssemblyAI Voice Agent API vs Inworld Realtime API](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-inworld-realtime.md)
- [Bland AI API + MCP vs fone.me](https://www.anchorterminal.com/compare/bland-ai-vs-fone-me.md)
- [Bland AI API + MCP vs Inworld Realtime API](https://www.anchorterminal.com/compare/bland-ai-vs-inworld-realtime.md)
- [Bolna API + MCP vs fone.me](https://www.anchorterminal.com/compare/bolna-vs-fone-me.md)
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- [Deepgram Voice Agent API vs fone.me](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-fone-me.md)
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- [ElevenLabs Agents API + MCP vs fone.me](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-fone-me.md)
- [ElevenLabs Agents API + MCP vs Inworld Realtime API](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-inworld-realtime.md)
- [fone.me vs Gemini Live API](https://www.anchorterminal.com/compare/fone-me-vs-gemini-live.md)
- [fone.me vs GPT-Live](https://www.anchorterminal.com/compare/fone-me-vs-gpt-live.md)
- [fone.me vs Harmony.ai](https://www.anchorterminal.com/compare/fone-me-vs-harmony-ai.md)
- [fone.me vs Hume EVI (Empathic Voice Interface)](https://www.anchorterminal.com/compare/fone-me-vs-hume-evi.md)
- [fone.me vs LiveKit Agents](https://www.anchorterminal.com/compare/fone-me-vs-livekit-agents.md)
- [fone.me vs OpenAI Realtime API](https://www.anchorterminal.com/compare/fone-me-vs-openai-realtime.md)
- [fone.me vs Pipecat](https://www.anchorterminal.com/compare/fone-me-vs-pipecat.md)
- [fone.me vs PlaceCall](https://www.anchorterminal.com/compare/fone-me-vs-placecall.md)
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- [fone.me vs Rime Prism](https://www.anchorterminal.com/compare/fone-me-vs-rime-prism.md)
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- [fone.me vs Ultravox Realtime API](https://www.anchorterminal.com/compare/fone-me-vs-ultravox.md)
- [fone.me vs Vaani Developer Platform](https://www.anchorterminal.com/compare/fone-me-vs-vaani-voice.md)
- [fone.me vs Vapi API + MCP](https://www.anchorterminal.com/compare/fone-me-vs-vapi.md)
- [fone.me vs Vocily AI](https://www.anchorterminal.com/compare/fone-me-vs-vocily.md)
- [fone.me vs Vogent API](https://www.anchorterminal.com/compare/fone-me-vs-vogent.md)
- [Gemini Live API vs Inworld Realtime API](https://www.anchorterminal.com/compare/gemini-live-vs-inworld-realtime.md)
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- [Harmony.ai vs Inworld Realtime API](https://www.anchorterminal.com/compare/harmony-ai-vs-inworld-realtime.md)
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- [Inworld Realtime API vs LiveKit Agents](https://www.anchorterminal.com/compare/inworld-realtime-vs-livekit-agents.md)
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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp