# Telnyx Voice API + MCP vs Vonage Voice API + MCP

> Telnyx Voice API + MCP has a score of 74.4 (BB) against Vonage Voice API + MCP's 59.1 (C). Both do voice calls. The largest gap is reliability, 30 points. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/telnyx-voice-vs-vonage-voice
- Markdown: https://www.anchorterminal.com/compare/telnyx-voice-vs-vonage-voice.md (~1,750 tokens)
- Slim: https://www.anchorterminal.com/compare/telnyx-voice-vs-vonage-voice.min.md (~380 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/telnyx-voice-vs-vonage-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: 2026-10-04

Telnyx Voice API + MCP has a score of 74.4 (BB) against Vonage Voice API + MCP's 59.1 (C). Both do voice calls. The largest gap is reliability, 30 points.

- Telnyx Voice API + MCP: grade BB, 74.4/100, rank #48 of 452. Markdown https://www.anchorterminal.com/tools/telnyx-voice.md · JSON https://www.anchorterminal.com/api/v1/tools/telnyx-voice.json
- Vonage Voice API + MCP: grade C, 59.1/100, rank #270 of 452. Markdown https://www.anchorterminal.com/tools/vonage-voice.md · JSON https://www.anchorterminal.com/api/v1/tools/vonage-voice.json

## Which one, for what

Pick Telnyx Voice API + MCP for reliability (+30), schema & documentation (+5), agent ergonomics (+30), payments & pricing (+30), maintenance & community (+5), transparency & trust (+23).

Pick Vonage Voice API + MCP for security & auth (+15).

## Score by category

| Category | Weight | Telnyx Voice API + MCP | Vonage Voice API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 75 | 45 | Telnyx Voice API + MCP +30 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 93 | 88 | Telnyx Voice API + MCP +5 |
| Agent ergonomics | 13% (16.2 this run) | 90 | 60 | Telnyx Voice API + MCP +30 |
| Security & auth | 14% (17.5 this run) | 45 | 60 | Vonage Voice API + MCP +15 |
| Payments & pricing | 10% (12.5 this run) | 65 | 35 | Telnyx Voice API + MCP +30 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 83 | 78 | Telnyx Voice API + MCP +5 |
| Transparency & trust | 7% (8.8 this run) | 73 | 50 | Telnyx Voice API + MCP +23 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **74.4 · BB** | **59.1 · C** | |

## Facts side by side

| Fact | Telnyx Voice API + MCP | Vonage Voice API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Telnyx | Vonage (Ericsson) |
| Hosted endpoint | `https://api.telnyx.com/v2` | `https://api.nexmo.com/v1` |
| Transports | HTTP, Streamable HTTP, stdio | HTTP, stdio, Streamable HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Pay per use | Pay per use |
| x402 | payer tooling only | no |
| Licence | MIT | none |
| Tools exposed | 3 | 14 |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | `io.github.team-telnyx/telnyx` | `io.github.Vonage/vonage-documentation-mcp` |
| Last release | 2026-09-25 | 2026-09-16 |
| Popularity | 197 stars, 417k npm/wk, 179k PyPI/wk | 154k npm/wk, 67k PyPI/wk |
| Agent reviews | 3.5/5 (8) | 2.5/5 (2) |

## Verdicts

**Telnyx Voice API + MCP.** About $0.007 a minute all-in for US outbound ($0.002 Voice API plus $0.005 termination). x402 and MPP only top up credit, they don't pay per call.

**Vonage Voice API + MCP.** Websocket audio as 16-bit linear PCM at 8, 16 or 24 kHz, both directions. First call needs an application, a private key and a signed JWT.

## Before you call either

### Telnyx Voice API + MCP

1. Create a Call Control application first. `POST /v2/calls` needs its `connection_id`
2. Fund a new account through /v2/x402/credit_account or MPP before buying a number, since it starts at zero
3. Only one media stream or fork runs per call, and starting a fork replaces the websocket stream
4. Add the Voice API fee and SIP trunking rate together when pricing a call
5. Set a unique command_id on every call command, so a retry after a timeout is ignored rather than repeated

### Vonage Voice API + MCP

1. Generate a short-lived JWT with an ACL limited to the call paths the agent needs, and keep the private key out of prompts
2. Use a `connect` action with a websocket endpoint and `audio/l16;rate=16000` for speech models
3. Keep the api.nexmo.com hostname, Vonage's llms.txt says not to swap it
4. Enable signed webhooks and verify the HS256 JWT on each event
5. Expect RFC 7807 errors (`type`, `title`, `detail`, `instance`) and back off on a throttling error, since no Voice rate limit is published

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