# Retell AI API + MCP vs Ultravox Realtime API (slim)

> Retell AI API + MCP has a score of 69.4 (B) against Ultravox Realtime API's 58.6 (C). Both do voice agent. The largest gap is maintenance & community, 42 points. Category scores, facts, verdicts and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/retell-ai-vs-ultravox.md (~1,600 tokens) · this version ~330 tokens · JSON https://www.anchorterminal.com/compare/retell-ai-vs-ultravox.json · canonical https://www.anchorterminal.com/compare/retell-ai-vs-ultravox
- Index: https://www.anchorterminal.com/llms.txt · 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 Ultravox Realtime API's 58.6 (C). Both do voice agent. The largest gap is maintenance & community, 42 points.

- Retell AI API + MCP: B 69.4, rank #114 of 452 · https://www.anchorterminal.com/tools/retell-ai.min.md
- Ultravox Realtime API: C 58.6, rank #279 of 452 · https://www.anchorterminal.com/tools/ultravox.min.md
- Pick Retell AI API + MCP for reliability (+8), schema & documentation (+8), security & auth (+30), maintenance & community (+42). Pick Ultravox Realtime API for agent ergonomics (+9).

| Category | Retell AI API + MCP | Ultravox Realtime API |
| --- | --- | --- |
| Reliability (16%) | 60 | 52 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 92 | 84 |
| Agent ergonomics (13%) | 60 | 69 |
| Security & auth (14%) | 76 | 46 |
| Payments & pricing (10%) | 40 | 40 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 85 | 43 |
| Transparency & trust (7%) | 79 | 75 |