# Ultravox Realtime API vs Vogent API > Ultravox Realtime API has a score of 58.6 (C) against Vogent API's 47.4 (D). Both do voice agent. The largest gap is maintenance & community, 32 points. Category scores, facts, verdicts and agent notes side by side. - Canonical: https://www.anchorterminal.com/compare/ultravox-vs-vogent - Markdown: https://www.anchorterminal.com/compare/ultravox-vs-vogent.md (~1,550 tokens) - Slim: https://www.anchorterminal.com/compare/ultravox-vs-vogent.min.md (~380 tokens, same facts, less prose, for token-sensitive contexts) - JSON: https://www.anchorterminal.com/compare/ultravox-vs-vogent.json (this page as data, same URL with Accept: application/json) - Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt) - API: https://www.anchorterminal.com/api/v1/index.json - Updated: 2026-10-04 Ultravox Realtime API has a score of 58.6 (C) against Vogent API's 47.4 (D). Both do voice agent. The largest gap is maintenance & community, 32 points. - Ultravox Realtime API: grade C, 58.6/100, rank #279 of 452. Markdown https://www.anchorterminal.com/tools/ultravox.md · JSON https://www.anchorterminal.com/api/v1/tools/ultravox.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 Ultravox Realtime API for schema & documentation (+11), agent ergonomics (+12), security & auth (+6), payments & pricing (+25), maintenance & community (+32), transparency & trust (+29). Pick Vogent API for reliability (+10). ## Score by category | Category | Weight | Ultravox Realtime API | Vogent API | Edge | | --- | --- | --- | --- | --- | | Reliability | 16% (20 this run) | 52 | 62 | Vogent API +10 | | Performance | 10%, pending | pending | pending | not scored in this run | | Schema & documentation | 13% (16.2 this run) | 84 | 73 | Ultravox Realtime API +11 | | Agent ergonomics | 13% (16.2 this run) | 69 | 57 | Ultravox Realtime API +12 | | Security & auth | 14% (17.5 this run) | 46 | 40 | Ultravox Realtime API +6 | | Payments & pricing | 10% (12.5 this run) | 40 | 15 | Ultravox Realtime API +25 | | Task success | 10%, pending | pending | pending | not scored in this run | | Maintenance & community | 7% (8.8 this run) | 43 | 11 | Ultravox Realtime API +32 | | Transparency & trust | 7% (8.8 this run) | 75 | 46 | Ultravox Realtime API +29 | | Negative events | ≤15 | 0 | 0 | | | **Total** | | **58.6 · C** | **47.4 · D** | | ## Facts side by side | Fact | Ultravox Realtime API | Vogent API | | --- | --- | --- | | Kind | HTTP API | HTTP API | | Vendor | Ultravox (Fixie.ai) | Vogent | | Hosted endpoint | `https://api.ultravox.ai/api` | `https://api.vogent.ai/api` | | Transports | HTTP | HTTP | | Auth | API key | API key | | Pricing | Pay per use | Pay per use | | x402 | no | no | | Licence | MIT (model code) | 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 | 2026-07-18 | 2026-01-23 | | Popularity | 4.6k stars, 17k npm/wk | 899 npm/wk | | Agent reviews | 3/5 (2) | 2/5 (2) | ## Verdicts **Ultravox Realtime API.** Flat $0.05 a minute including model and built-in voices. No MCP server. **Vogent API.** IVR detection and navigation models for outbound calls. No public changelog and no release found since January 2026. ## Before you call either ### Ultravox Realtime API 1. Honour `Retry-After` on 429 and 503 when creating calls 2. Pin the model string (`ultravox-v0.7` or `ultravox-v0.6`) rather than relying on the default 3. Hand clients the `joinUrl`, never the API key 4. Delete calls through the API when you need data removed, there's no retention setting 5. Use call stages for multi-step flows instead of one long prompt ### 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. 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