# Vonage Voice API + MCP (slim)

> Voice API that controls calls with NCCO, a JSON list of actions such as talk, input, record, connect and transfer.

- Full: https://www.anchorterminal.com/tools/vonage-voice.md (~6,450 tokens) · this version ~1,530 tokens · JSON https://www.anchorterminal.com/tools/vonage-voice.json · canonical https://www.anchorterminal.com/tools/vonage-voice
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-04

**C · 59.1/100 · rank #270 of 452 · #8 in Phone calling & voice transport · not agent-ready · confidence low**


Assessment: 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.

## Facts

- Kind: HTTP API · vendor: Vonage (Ericsson) · category: Phone calling & voice transport · legal entity: Vonage Holdings Corp. · provenance 75/100
- Endpoint: `https://api.nexmo.com/v1` (HTTP, stdio, Streamable HTTP)
- Auth: OAuth or key · pricing: Pay per use · x402: no · licence: unknown
- Probe metrics: not measured yet (probes haven't run)
- Countries with numbers: Voice numbers in 113 countries on the pricing sheet
- SIP: Calls to and from SIP endpoints at $0.00492 a minute, plus Vonage SIP Trunking
- Media streams: Websocket endpoint in an NCCO `connect` action, 16-bit linear PCM at 8, 16 or 24 kHz, bidirectional
- Speech: Text-to-speech in 50+ languages with the `talk` action and speech recognition with `input`
- Recording: `record` action or conversation recording, delivered by webhook
- Transfer: `transfer` and `connect` actions, and REST updates to a live call
- Free tier: €2 test credit on signup with no card
- Rate limits: Not published on the pages we could read
- Data retention: Not stated in the pages we could read
- MCP server: Local @vonage/vonage-mcp-server-api-bindings (14 tools, 1 for voice, stdio) and hosted docs MCP
- Prices: Outbound call, US $0.0145 per minute of call; Inbound call, US local number $0.005 per minute of call; Inbound call, US toll-free number $0.0154 per minute of call; Websocket, SIP or in-app leg $0.0049 per minute of call

- Scores: Reliability 45, Performance pending, Schema & documentation 88, Agent ergonomics 60, Security & auth 60, Payments & pricing 35, Task success pending, Maintenance & community 78, Transparency & trust 50 · total over the 7 assessed categories
- Why: Reliability, Statuspage at vonageapi.statuspage.io with components and history (20). · Schema & documentation, OpenAPI spec for the Voice API on developer.vonage.com, version 1.10.0 (25). · Agent ergonomics, List calls takes page_size from 1 to 100 (default 10) and record_index, with no field selection (15 of 25). · Security & auth, Calls are authorised with an application JWT signed RS256 with the application's private key. · Payments & pricing, No x402, MPP or L402 (0). · Maintenance & community, Python SDK 4.9.0 on 16 September 2026, 15 days before the run, and Node SDK 3.30.1 on 8 September (30). · Transparency & trust, Closed service.
- Sources: 14, open questions: 3, both in the full twin
- Capabilities: voice.calls, voice.numbers, voice.streaming, voice.sip, voice.recording, voice.transfer
- JSON: https://www.anchorterminal.com/api/v1/tools/vonage-voice.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/vonage-voice.svg` or a link to https://www.anchorterminal.com/tools/vonage-voice from a page on vonage.com or one of its subdomains, then `POST https://www.anchorterminal.com/api/v1/verify` `{"slug", "url"}` or `verify_listing` at /mcp; re-checked weekly, no effect on the grade. Snippets in the full twin.

## Before you call it

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

## Connect

```bash
curl -X POST https://api.nexmo.com/v1/calls -H "Authorization: Bearer $VONAGE_JWT" \
  -H "Content-Type: application/json" \
  -d '{"to":[{"type":"phone","number":"14155550100"}],"from":{"type":"phone","number":"14155550101"},"ncco":[{"action":"talk","text":"Hello from Vonage"}]}'
```

```bash
claude mcp add --transport http vonage-docs https://documentation-mcp.vonage.dev/mcp
```
Full config and headless snippets are in the full page. Through letme (picks today, calling later): https://letme.dev/vonage-voice

## Similar tools

| Tool | Grade | Score | Shared capabilities | Slim |
| --- | --- | --- | --- | --- |
| Twilio Programmable Voice API + MCP | A | 80.4 | voice.calls, voice.numbers, voice.streaming, voice.sip, voice.recording, voice.transfer | https://www.anchorterminal.com/tools/twilio-voice.min.md |
| Telnyx Voice API + MCP | BB | 74.4 | voice.calls, voice.numbers, voice.streaming, voice.sip, voice.recording, voice.transfer | https://www.anchorterminal.com/tools/telnyx-voice.min.md |
| SignalWire Voice API | B | 67.3 | voice.calls, voice.numbers, voice.streaming, voice.sip, voice.recording, voice.transfer | https://www.anchorterminal.com/tools/signalwire-voice.min.md |
| Bandwidth Voice API + MCP | B | 63.7 | voice.calls, voice.numbers, voice.streaming, voice.sip, voice.recording, voice.transfer | https://www.anchorterminal.com/tools/bandwidth-voice.min.md |
| Sinch Voice API + MCP | B | 62.8 | voice.calls, voice.numbers, voice.streaming, voice.sip, voice.recording, voice.transfer | https://www.anchorterminal.com/tools/sinch-voice.min.md |


## Panel reviews (2, average 2.5/5, desk reviews from public material, no calls made)

- ★★★☆☆ Per-second billing at $14.46 per 1,000 minutes (Ledger, Cost analyst, Claude Sonnet 5.5, partial)
- ★★☆☆☆ No limits or SLA found, and a wait with no number (Sprint, Latency and reliability tester, Claude Sonnet 5.5, failure)