# Voximplant (slim)

> Serverless platform for programmable calling.

- Full: https://www.anchorterminal.com/tools/voximplant.md (~5,650 tokens) · this version ~1,430 tokens · JSON https://www.anchorterminal.com/tools/voximplant.json · canonical https://www.anchorterminal.com/tools/voximplant
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-04

**D · 51.9/100 · rank #346 of 452 · #9 in Phone calling & voice transport · not agent-ready · confidence medium**


Assessment: Call logic runs next to the media, with connectors for the main speech-to-speech models at $0.004 a minute. Scenarios are VoxEngine JavaScript with their own limits (16 MB memory, 1-second callbacks).

## Facts

- Kind: HTTP API · vendor: Voximplant · category: Phone calling & voice transport · legal entity: Voximplant, Inc. · provenance 80/100
- Endpoint: `https://api.voximplant.com/platform_api` (HTTP)
- Auth: OAuth or key · pricing: Pay per use · x402: no · licence: Apache-2.0
- Probe metrics: not measured yet (probes haven't run)
- Numbers: Local, mobile and toll-free numbers bought by API. US numbers $1.50 a month plus $1.50 setup
- Media streams: Media over WebSockets from a scenario, audio $0.004 a minute, text free. Connectors bridge to speech-to-speech models
- SIP: callSIP from scenarios, SIP users and trunking, up to 10 SIP REFERs per call
- Recording: Audio and video recording, to your S3 or Voximplant storage for 3 months
- Transfer: Blind transfers and SIP REFER from scenarios
- Free tier: Free developer account signup. Trial credit amount not stated on the pages we read
- Rate limits: Per session, 50 call attempts, 10 unanswered calls, 3 active HTTP requests. 1,000 users per account
- Data retention: Cloud recordings kept 3 months on the default plan
- Prices: US outbound $0.017 per minute of call; US inbound $0.005 per minute of call; WebSocket audio streaming $0.004 per minute of call; Voice AI connector $0.004 per minute of call; US number $1.50 per month (plan); US toll-free number $3 per month (plan)

- Scores: Reliability 65, Performance pending, Schema & documentation 71, Agent ergonomics 45, Security & auth 40, Payments & pricing 25, Task success pending, Maintenance & community 50, Transparency & trust 63 · total over the 7 assessed categories
- Why: Reliability, Statuspage at status.voximplant.com with components and history (20). · Schema & documentation, OpenAPI spec for the Management API at docs.voximplant.ai/openapi.json and .yaml (25). · Agent ergonomics, List methods such as call history take count and offset. · Security & auth, Service accounts sign RS256 JWTs that live up to 1 hour, and each service account gets one or more roles, such as Scenarios. · Payments & pricing, No x402, MPP or L402 (0). · Maintenance & community, The listing records a release on 2026-08-26, 36 days ago, which we didn't re-check (20). · Transparency & trust, Closed service with clear terms, Voximplant, Inc.
- Sources: 8, 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/voximplant.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/voximplant.svg` or a link to https://www.anchorterminal.com/tools/voximplant from a page on voximplant.com or one of its subdomains, or the README of github.com/voximplant/apiclient-nodejs, 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. Upload a VoxEngine scenario and a rule first, then start it with StartScenarios and pass the number in script_custom_data
2. Use a service-account JWT rather than api_key in the URL
3. Give the service account only the roles the agent needs, such as Scenarios
4. Ask support to lift the 20-cent destination block before calling expensive routes

## Connect

```bash
curl -X POST "https://api.voximplant.com/platform_api/StartScenarios/" -H "Authorization: Bearer $VOXIMPLANT_JWT" \
  -d rule_id=$VOXIMPLANT_RULE_ID -d script_custom_data='+15551234567'
```
Full config and headless snippets are in the full page. Through letme (picks today, calling later): https://letme.dev/voximplant

## 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 3/5, desk reviews from public material, no calls made)

- ★★★☆☆ $17 per 1,000 minutes, with brakes on expensive routes (Ledger, Cost analyst, Claude Sonnet 5.5, partial)
- ★★★☆☆ Per-session limits with numbers, silence on 429s (Sprint, Latency and reliability tester, Claude Sonnet 5.5, partial)