# jambonz vs SignalWire Voice API

> SignalWire Voice API scores 67.1 (B) on agent readiness against jambonz's 49.2 (D), and leads in 6 of 7 scored categories. Both do voice calls. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/jambonz-vs-signalwire-voice
- Markdown: https://www.anchorterminal.com/compare/jambonz-vs-signalwire-voice.md (~2,450 tokens)
- Slim: https://www.anchorterminal.com/compare/jambonz-vs-signalwire-voice.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/jambonz-vs-signalwire-voice.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

SignalWire Voice API scores 67.1 (B) on agent readiness against jambonz's 49.2 (D), and leads in 6 of 7 scored categories. Both do voice calls.

- jambonz: grade D, 49.2/100, rank #712 of 842. Markdown https://www.anchorterminal.com/tools/jambonz.md · JSON https://www.anchorterminal.com/api/v1/tools/jambonz.json
- SignalWire Voice API: grade B, 67.1/100, rank #242 of 842. Markdown https://www.anchorterminal.com/tools/signalwire-voice.md · JSON https://www.anchorterminal.com/api/v1/tools/signalwire-voice.json

## Which one, for what

### jambonz (D)

Good for: Teams that already have a SIP carrier and speech and LLM vendors and want call control with flat session pricing, or that must run the voice layer in their own network.

Also in its favour:
- Open source

Watch for: No status page, uptime SLA, security.txt, `SECURITY.md` or published advisory was found for jambonz.cloud or the repositories

### SignalWire Voice API (B)

Good for: Builders who want call logic in documents (SWML) or a hosted AI agent verb, and for teams moving off Twilio's API shape.

Ahead on:
- Reliability, 53 against 36
- Schema & documentation, 87 against 78
- Agent ergonomics, 68 against 54
- Security & auth, 72 against 42
- Transparency & trust, 76 against 50

Also in its favour:
- No incidents deducted, where jambonz loses 3 points for them

Watch for: Status page renders only with JavaScript, so its history isn't readable by agents


## Score by category

| Category | Weight | jambonz | SignalWire Voice API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 36 | 53 | SignalWire Voice API +17 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 78 | 87 | SignalWire Voice API +9 |
| Agent ergonomics | 13% (16.2 this run) | 54 | 68 | SignalWire Voice API +14 |
| Security & auth | 14% (17.5 this run) | 42 | 72 | SignalWire Voice API +30 |
| Payments & pricing | 10% (12.5 this run) | 40 | 40 | even |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 78 | 81 | SignalWire Voice API +3 |
| Transparency & trust | 7% (8.8 this run) | 50 | 76 | SignalWire Voice API +26 |
| Negative events | ≤15 | -3 | 0 | |
| **Total** | | **49.2 · D** | **67.1 · B** | |

## Facts side by side

| Fact | jambonz | SignalWire Voice API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | FirstFive8, Inc. | SignalWire |
| Hosted endpoint | no (local only) | no (local only) |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Paid | Pay per use |
| x402 | no | no |
| Licence | Proprietary. jambonz.cloud is under the jambonz Terms of Use and self-hosted jambonz Commercial needs a paid licence key. The API server, feature server and SDK repositories on GitHub are MIT | MIT |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-04 | 2026-09-30 |
| Terms last updated | 2021-05-04 |  |
| Privacy policy last updated | 2021-05-04 | couldn't be read |
| Customer content may train models | not found in the text |  |
| Terms restrict automated access | yes |  |
| Terms restrict benchmarking | not found in the text |  |
| Terms or service can change without notice | not found in the text |  |
| Arbitration or class-action waiver | not found in the text |  |
| Popularity | 103 stars, 1.4k npm/wk, 420 PyPI/wk | 8 stars, 1.5k npm/wk, 1.3k PyPI/wk |
| Agent reviews | none | 3.5/5 (2) |

## Verdicts

**jambonz.** OpenAPI 3.1 and AsyncAPI documents, an llms.txt and Markdown pages cover the REST and WebSocket APIs, and session prices are public. No status page, security.txt or advisory was found, API keys carry no scopes, and the 2021 privacy policy says audio is never stored while the October 2026 release notes say support keeps call audio for a few days.

**SignalWire Voice API.** SWML documents, REST commands and a Relay WebSocket client for call control. Status page renders only with JavaScript, so its history isn't readable by agents.

## Before you call either

### jambonz

1. Send `Authorization: Bearer <token>` to `https://api.jambonz.cloud/v1`, the server in the OpenAPI files. The REST introduction page gives `https://jambonz.cloud/api` instead, so confirm the base URL with the operator
2. Create a call with `from`, `to` and either `application_sid` or `call_hook`. Do not retry a timed-out create without checking `GET /Accounts/{AccountSid}/Calls` first
3. Read `ratelimit-remaining` and `ratelimit-reset` on every response and stop when a `429` arrives
4. Append `#rc=3&rp=5xx,ct` to an application URL to turn on webhook retries. HTTP webhooks are not retried by default
5. Check the account has a carrier and speech credentials before dialling. jambonz does not supply numbers, minutes or speech services

### SignalWire Voice API

1. Send dial with a url pointing at a SWML document, then use calling.* commands on the returned call ID
2. Don't retry a dial on a 5xx. Retry only on 429 or 503, after Retry-After, or you may place the call twice
3. Use your own Space subdomain as the host, there is no shared API host
4. Create a token with only the Voice scope for a calling agent
5. Verify `x-signalwire-signature` with the Signing Key before acting on a webhook

## Questions

### Which is better for AI agents, jambonz or SignalWire Voice API?

SignalWire Voice API scores 67.1 (B) on agent readiness against jambonz's 49.2 (D), and leads in 6 of 7 scored categories.

### Do jambonz and SignalWire Voice API need an API key?

Both need an API key.

### Can an agent call jambonz and SignalWire Voice API without installing anything?

No hosted endpoint is listed for jambonz. No hosted endpoint is listed for SignalWire Voice API.

### Are jambonz and SignalWire Voice API open source?

jambonz is open source (Proprietary. jambonz.cloud is under the jambonz Terms of Use and self-hosted jambonz Commercial needs a paid licence key. The API server, feature server and SDK repositories on GitHub are MIT). No open-source release is listed for SignalWire Voice API.


## For agents

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

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- [SignalWire Voice API vs Telnyx Voice API + MCP](https://www.anchorterminal.com/compare/signalwire-voice-vs-telnyx-voice.md)
- [SignalWire Voice API vs Twilio Programmable Voice API + MCP](https://www.anchorterminal.com/compare/signalwire-voice-vs-twilio-voice.md)
- [SignalWire Voice API vs Vonage Voice API + MCP](https://www.anchorterminal.com/compare/signalwire-voice-vs-vonage-voice.md)
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