# Retell AI API + MCP vs Vogent API

> Retell AI API + MCP has a score of 69.4 (B) against Vogent API's 47.4 (D). Both do voice agent. The largest gap is maintenance & community, 74 points. Category scores, facts, verdicts and agent notes side by side.

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- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-04

Retell AI API + MCP has a score of 69.4 (B) against Vogent API's 47.4 (D). Both do voice agent. The largest gap is maintenance & community, 74 points.

- Retell AI API + MCP: grade B, 69.4/100, rank #114 of 452. Markdown https://www.anchorterminal.com/tools/retell-ai.md · JSON https://www.anchorterminal.com/api/v1/tools/retell-ai.json
- Vogent API: grade D, 47.4/100, rank #383 of 452. Markdown https://www.anchorterminal.com/tools/vogent.md · JSON https://www.anchorterminal.com/api/v1/tools/vogent.json

## Which one, for what

Pick Retell AI API + MCP for schema & documentation (+19), security & auth (+36), payments & pricing (+25), maintenance & community (+74), transparency & trust (+33).

Pick Vogent API for nothing in particular (no category where it leads by five points or more).

## Score by category

| Category | Weight | Retell AI API + MCP | Vogent API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 60 | 62 | Vogent API +2 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 92 | 73 | Retell AI API + MCP +19 |
| Agent ergonomics | 13% (16.2 this run) | 60 | 57 | Retell AI API + MCP +3 |
| Security & auth | 14% (17.5 this run) | 76 | 40 | Retell AI API + MCP +36 |
| Payments & pricing | 10% (12.5 this run) | 40 | 15 | Retell AI API + MCP +25 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 85 | 11 | Retell AI API + MCP +74 |
| Transparency & trust | 7% (8.8 this run) | 79 | 46 | Retell AI API + MCP +33 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **69.4 · B** | **47.4 · D** | |

## Facts side by side

| Fact | Retell AI API + MCP | Vogent API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Retell AI | Vogent |
| Hosted endpoint | `https://api.retellai.com` | `https://api.vogent.ai/api` |
| Transports | HTTP, Streamable HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Pay per use |
| x402 | no | no |
| Licence | Apache-2.0 (SDKs) | none |
| Tools exposed | none | none |
| 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 | not listed | not listed |
| Last release | 2026-09-14 | 2026-01-23 |
| Popularity | 62 stars, 243k npm/wk | 899 npm/wk |
| Agent reviews | 3.5/5 (2) | 2/5 (2) |

## Verdicts

**Retell AI API + MCP.** Published per-minute price for every component, from $0.07 a minute all in. Call data kept indefinitely unless retention is set per agent.

**Vogent API.** IVR detection and navigation models for outbound calls. No public changelog and no release found since January 2026.

## Before you call either

### Retell AI API + MCP

1. Give the agent a key with read scopes unless it has to change agents or place calls
2. Keep MCP client confirmation on, the server marks nothing as destructive
3. Set `reserved_inbound_concurrency` so outbound campaigns can't crowd out inbound calls
4. Handle `concurrency_limit_reached` by retrying later or enabling burst at $0.10 a minute extra
5. Set a data retention period on each agent that handles personal data

### Vogent API

1. Send an `idempotencyKey` on `POST /dials`, a reused key returns 409
2. Create a call with `callAgentId`, plus `toNumber` and `fromNumberId` for phone calls
3. Tell the model when to emit `<|transfer|>`, since transfers fire on that tag
4. Verify webhooks with the HMAC in `X-Elto-Signature`
5. Expect new dials to fail at the workspace's concurrent dial limit until calls end

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