# Phone calling and voice transport APIs for agents (slim)

> 10 phone calling & voice transport listings ranked by the Anchor benchmark. Leader Twilio Programmable Voice API + MCP (A). The calling layer an agent connects to. Numbers, inbound and outbound calls, audio streaming over websockets or SIP, transfers and recordings. Compared on setup, webhook reliability, where numbers are available and the full cost of a call.

- Full: https://www.anchorterminal.com/categories/voice-calling.md (~2,950 tokens) · this version ~580 tokens · JSON https://www.anchorterminal.com/categories/voice-calling.json · canonical https://www.anchorterminal.com/categories/voice-calling
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-04

- Tools: 10 · agent-ready (BB+): 2 · accept x402: 1 · JSON: https://www.anchorterminal.com/api/v1/tools.json · by capability: https://www.anchorterminal.com/api/v1/capabilities.json
- Capabilities: voice.calls, voice.numbers, voice.streaming, voice.sip, voice.recording

| # | Tool | Grade | Score | Confidence | x402 | Auth | Where | Slim |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 6 | Twilio Programmable Voice API + MCP | A | 80.4 | medium | no | OAuth or key | hosted + local | https://www.anchorterminal.com/tools/twilio-voice.min.md |
| 48 | Telnyx Voice API + MCP | BB | 74.4 | medium | payer | OAuth or key | hosted + local | https://www.anchorterminal.com/tools/telnyx-voice.min.md |
| 144 | SignalWire Voice API | B | 67.3 | medium | no | API key | local | https://www.anchorterminal.com/tools/signalwire-voice.min.md |
| 196 | Bandwidth Voice API + MCP | B | 63.7 | medium | no | OAuth | hosted + local | https://www.anchorterminal.com/tools/bandwidth-voice.min.md |
| 212 | Sinch Voice API + MCP | B | 62.8 | medium | no | OAuth or key | hosted + local | https://www.anchorterminal.com/tools/sinch-voice.min.md |
| 246 | Infobip Calls API + MCP | C | 60.5 | medium | no | OAuth or key | hosted | https://www.anchorterminal.com/tools/infobip-calls.min.md |
| 248 | Plivo Voice API | C | 60.4 | medium | no | API key | hosted | https://www.anchorterminal.com/tools/plivo-voice.min.md |
| 270 | Vonage Voice API + MCP | C | 59.1 | low | no | OAuth or key | hosted + local | https://www.anchorterminal.com/tools/vonage-voice.min.md |
| 346 | Voximplant | D | 51.9 | medium | no | OAuth or key | hosted | https://www.anchorterminal.com/tools/voximplant.min.md |
| 424 | Exotel Voice API + MCP | E | 39.8 | medium | no | API key | hosted | https://www.anchorterminal.com/tools/exotel-voice.min.md |