# Bolna API + MCP vs Inworld Realtime API

> Inworld Realtime scores 60.1 (C) to Bolna's 44.7 (E) for voice agents. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/bolna-vs-inworld-realtime
- Markdown: https://www.anchorterminal.com/compare/bolna-vs-inworld-realtime.md (~5,200 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 Bolna API + MCP's 44.7 (E), and leads in 4 of 7 scored categories. Bolna API + MCP leads on maintenance & community. Both do voice agents.

- Bolna API + MCP: grade E, 44.7/100, rank #1210 of 1510. Markdown https://www.anchorterminal.com/tools/bolna.md · JSON https://www.anchorterminal.com/api/v1/tools/bolna.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

### Bolna API + MCP (E)

Good 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:
- Maintenance & community, 76 against 71

Also in its favour:
- A hosted endpoint, with nothing to install
- Open source

Watch for: Unsigned webhooks and tool calls, IP allowlisting only

### 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 40
- Agent ergonomics, 68 against 52
- Security & auth, 58 against 44
- Payments & pricing, 40 against 30

Also in its favour:
- No incidents deducted, where Bolna API + MCP loses 6 points for them

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

### Reliability: Inworld Realtime API +22

- 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.
- 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.

### Agent ergonomics: Inworld Realtime API +16

- 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.
- 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.

### Security & auth: Inworld Realtime API +14

- Bolna API + MCP (44): Bearer keys shown once and stored hashed, revocable from the dashboard, with separate `sa-` keys for enterprise sub-accounts (25). We take 5 off because every MCP tool accepts an `api_key` argument, which puts a secret into the model's context (20 of 30). Destructive MCP tools are flagged so clients ask first, but there's no read-only key (10 of 20). Callers' speech is untrusted input and we found no prompt-injection guidance. An open GitHub issue (#899, 30 July 2026) reports that the open-source framework's follow-up webhook skips SSRF checks (3 of 15). Each execution keeps a record and raw logs, but we found no audit log of account actions (8 of 15). No security.txt, no bug bounty, and no SOC 2 or ISO 27001 claim. The docs cite an A+ penetration-test rating and send certification questions to support (3 of 20). Webhooks and tool calls carry no signature, only three fixed source IPs. On 4 November the security page is unchanged, www.bolna.ai serves no security.txt (404), and osv.dev lists no advisory for `bolna`. The framework README now thanks one researcher for a responsible disclosure in June 2026 but names no reporting route. 20+10+3+8+3 = 44.
- 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.

### Payments & pricing: Inworld Realtime API +10

- 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.
- Inworld Realtime API (40): No x402, MPP or L402 (0). No per-session price, but each billed part (STT per hour, TTS per character, LLM per token) is priced publicly (20). On-Demand includes free STT and TTS allowances and lists no payment method, though some premium LLMs need a card on file (20). A person signs up in a browser before a key exists (0). Total 40.

### Maintenance & community: Bolna API + MCP +5

- 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.
- 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.

## Score by category

| Category | Weight | Bolna API + MCP | Inworld Realtime API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 40 | 62 | Inworld Realtime API +22 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 63 | 60 | Bolna API + MCP +3 |
| Agent ergonomics | 13% (16.2 this run) | 52 | 68 | Inworld Realtime API +16 |
| Security & auth | 14% (17.5 this run) | 44 | 58 | Inworld Realtime API +14 |
| Payments & pricing | 10% (12.5 this run) | 30 | 40 | Inworld Realtime API +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 76 | 71 | Bolna API + MCP +5 |
| Transparency & trust | 7% (8.8 this run) | 67 | 63 | Bolna API + MCP +4 |
| Negative events | ≤15 | -6 | 0 | |
| **Total** | | **44.7 · E** | **60.1 · C** | |

## Facts side by side

| Fact | Bolna API + MCP | Inworld Realtime API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Bolna | Inworld AI |
| Hosted endpoint | `https://api.bolna.ai` | no (local only) |
| Transports | HTTP, Streamable HTTP | websocket, HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Pay per use |
| Price for voice agents | not published | $25 per 1M characters |
| x402 | no | no |
| Licence | MIT | none |
| Tools exposed | 117 | 0 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-11-04 | 2026-10-16 |
| Terms last updated | 2026-08-13 | 2025-06-11 |
| Privacy policy last updated | 2025-03-28 | 2026-01-18 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | not found in the text |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | yes | not found in the text |
| Arbitration or class-action waiver | not found in the text | not found in the text |
| Popularity | 779 stars, 579 npm/wk, 2.6k PyPI/wk | none |
| Agent reviews | 2.5/5 (2) | none |

## How the scores have moved

### Bolna API + MCP

- -8.0 on 4 November 2026 (D to E): security, new evidence
- +0.1 on 28 October 2026: new evidence
- -0.3 on 8 October 2026: checklist

### Inworld Realtime API

No score change since it was listed.

## 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.

**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

### 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

### 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, Bolna API + MCP or Inworld Realtime API?

Inworld Realtime API scores 60.1 (C) on agent readiness against Bolna API + MCP's 44.7 (E), and leads in 4 of 7 scored categories. Bolna API + MCP leads on maintenance & community.

### Do Bolna API + MCP and Inworld Realtime API need an API key?

Both need an API key.

### Can an agent call Bolna API + MCP and Inworld Realtime API without installing anything?

Bolna API + MCP has a hosted endpoint at https://api.bolna.ai. No hosted endpoint is listed for Inworld Realtime API.

### Are Bolna API + MCP and Inworld Realtime API open source?

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


## For agents

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

## Other comparisons with Bolna API + MCP or Inworld Realtime API

- [Amazon Nova 2 Sonic vs Bolna API + MCP](https://www.anchorterminal.com/compare/amazon-nova-sonic-vs-bolna.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 Bolna API + MCP](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-bolna.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 Bolna API + MCP](https://www.anchorterminal.com/compare/bland-ai-vs-bolna.md)
- [Bland AI API + MCP vs Inworld Realtime API](https://www.anchorterminal.com/compare/bland-ai-vs-inworld-realtime.md)
- [Bolna API + MCP vs Deepgram Voice Agent API](https://www.anchorterminal.com/compare/bolna-vs-deepgram-voice-agent.md)
- [Bolna API + MCP vs ElevenLabs Agents API + MCP](https://www.anchorterminal.com/compare/bolna-vs-elevenlabs-agents.md)
- [Bolna API + MCP vs fone.me](https://www.anchorterminal.com/compare/bolna-vs-fone-me.md)
- [Bolna API + MCP vs Gemini Live API](https://www.anchorterminal.com/compare/bolna-vs-gemini-live.md)
- [Bolna API + MCP vs GPT-Live](https://www.anchorterminal.com/compare/bolna-vs-gpt-live.md)
- [Bolna API + MCP vs Harmony.ai](https://www.anchorterminal.com/compare/bolna-vs-harmony-ai.md)
- [Bolna API + MCP vs Hume EVI (Empathic Voice Interface)](https://www.anchorterminal.com/compare/bolna-vs-hume-evi.md)
- [Bolna API + MCP vs LiveKit Agents](https://www.anchorterminal.com/compare/bolna-vs-livekit-agents.md)
- [Bolna API + MCP vs OpenAI Realtime API](https://www.anchorterminal.com/compare/bolna-vs-openai-realtime.md)
- [Bolna API + MCP vs Pipecat](https://www.anchorterminal.com/compare/bolna-vs-pipecat.md)
- [Bolna API + MCP vs PlaceCall](https://www.anchorterminal.com/compare/bolna-vs-placecall.md)
- [Bolna API + MCP vs Retell AI API + MCP](https://www.anchorterminal.com/compare/bolna-vs-retell-ai.md)
- [Bolna API + MCP vs Rime Prism](https://www.anchorterminal.com/compare/bolna-vs-rime-prism.md)
- [Bolna API + MCP vs Synthflow API + MCP](https://www.anchorterminal.com/compare/bolna-vs-synthflow.md)
- [Bolna API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/bolna-vs-ultravox.md)
- [Bolna API + MCP vs Vaani Developer Platform](https://www.anchorterminal.com/compare/bolna-vs-vaani-voice.md)
- [Bolna API + MCP vs Vapi API + MCP](https://www.anchorterminal.com/compare/bolna-vs-vapi.md)
- [Bolna API + MCP vs Vocily AI](https://www.anchorterminal.com/compare/bolna-vs-vocily.md)
- [Bolna API + MCP vs Vogent API](https://www.anchorterminal.com/compare/bolna-vs-vogent.md)
- [Deepgram Voice Agent API vs Inworld Realtime API](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-inworld-realtime.md)
- [ElevenLabs Agents API + MCP vs Inworld Realtime API](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-inworld-realtime.md)
- [fone.me vs Inworld Realtime API](https://www.anchorterminal.com/compare/fone-me-vs-inworld-realtime.md)
- [Gemini Live API vs Inworld Realtime API](https://www.anchorterminal.com/compare/gemini-live-vs-inworld-realtime.md)
- [GPT-Live vs Inworld Realtime API](https://www.anchorterminal.com/compare/gpt-live-vs-inworld-realtime.md)
- [Harmony.ai vs Inworld Realtime API](https://www.anchorterminal.com/compare/harmony-ai-vs-inworld-realtime.md)
- [Hume EVI (Empathic Voice Interface) vs Inworld Realtime API](https://www.anchorterminal.com/compare/hume-evi-vs-inworld-realtime.md)
- [Inworld Realtime API vs LiveKit Agents](https://www.anchorterminal.com/compare/inworld-realtime-vs-livekit-agents.md)
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- [Inworld Realtime API vs Rime Prism](https://www.anchorterminal.com/compare/inworld-realtime-vs-rime-prism.md)
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- [Inworld Realtime API vs Vaani Developer Platform](https://www.anchorterminal.com/compare/inworld-realtime-vs-vaani-voice.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