# OpenAI Realtime API vs Vocily AI

> OpenAI Realtime scores 63.3 (B) to Vocily AI's 53.8 (D) for voice agents. Prices, MCP, x402, uptime and agent notes side by side.

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- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

OpenAI Realtime API scores 63.3 (B) on agent readiness against Vocily AI's 53.8 (D), and leads in 3 of 7 scored categories. Vocily AI leads on schema & documentation, agent ergonomics, payments & pricing and maintenance & community. Both do voice agents.

- OpenAI Realtime API: grade B, 63.3/100, rank #400 of 950. Markdown https://www.anchorterminal.com/tools/openai-realtime.md · JSON https://www.anchorterminal.com/api/v1/tools/openai-realtime.json
- Vocily AI: grade D, 53.8/100, rank #701 of 950. Markdown https://www.anchorterminal.com/tools/vocily.md · JSON https://www.anchorterminal.com/api/v1/tools/vocily.json
- Best conversational voice-agent APIs: https://www.anchorterminal.com/best/voice-agents/index.md
- All 91 voice agents comparisons: https://www.anchorterminal.com/compare/voice-agents/index.md

## Which one, for what

### OpenAI Realtime API (B)

Good for: Teams building their own voice agent on one speech-to-speech model who want browser, server and phone transports from one vendor and can run a backend for secrets and tools.

Ahead on:
- Reliability, 67 against 40
- Security & auth, 61 against 46
- Transparency & trust, 71 against 47

Also in its favour:
- No incidents deducted, where Vocily AI loses 5 points for them

Watch for: openai.com answered 403 to our reader, so the service terms, privacy policy, sub-processor list and security pages were not read.

### Vocily AI (D)

Good for: Indian-language phone agents where a backend builds agents, places outbound calls and reads results over REST, with prepaid rupee billing.

Ahead on:
- Schema & documentation, 90 against 84
- Agent ergonomics, 84 against 76
- Payments & pricing, 40 against 20
- Maintenance & community, 61 against 52

Watch for: No status page, incident history or SLA was found


## Score by category

| Category | Weight | OpenAI Realtime API | Vocily AI | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 67 | 40 | OpenAI Realtime API +27 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 84 | 90 | Vocily AI +6 |
| Agent ergonomics | 13% (16.2 this run) | 76 | 84 | Vocily AI +8 |
| Security & auth | 14% (17.5 this run) | 61 | 46 | OpenAI Realtime API +15 |
| Payments & pricing | 10% (12.5 this run) | 20 | 40 | Vocily AI +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 52 | 61 | Vocily AI +9 |
| Transparency & trust | 7% (8.8 this run) | 71 | 47 | OpenAI Realtime API +24 |
| Negative events | ≤15 | 0 | -5 | |
| **Total** | | **63.3 · B** | **53.8 · D** | |

## Facts side by side

| Fact | OpenAI Realtime API | Vocily AI |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | OpenAI | Vocily AI Private Limited |
| Hosted endpoint | `https://api.openai.com/v1/realtime` | `https://api.vocily.ai` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Pay per use |
| x402 | no | no |
| Licence | Proprietary service. The service terms on openai.com were not read. The Agents SDK for TypeScript and the OpenAPI description are MIT | Proprietary service under Vocily's terms of service. No open-source code or published package was found |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-07-28 | 2026-09-30 |
| Terms last updated | couldn't be read | 2026-06-10 |
| Privacy policy last updated | couldn't be read | 2026-09-03 |
| Customer content may train models | couldn't be read | not found in the text |
| Terms restrict automated access | couldn't be read | not found in the text |
| Terms restrict benchmarking | couldn't be read | not found in the text |
| Terms or service can change without notice | couldn't be read | not found in the text |
| Arbitration or class-action waiver | couldn't be read | not found in the text |

## Verdicts

**OpenAI Realtime API.** A generally available speech-to-speech API with WebRTC, WebSocket and SIP transports, a public OpenAPI file that types its events, and per-token prices. Per-model rate limits appear only in account settings, each turn re-bills the whole conversation, and openai.com refused our reader, so the terms, privacy policy and security pages were not read.

**Vocily AI.** The REST API is documented in detail for a product a few months old, with an OpenAPI 3.1 file, required idempotency keys on calls, a Retry-After header on 429 and signed webhooks. No status page, SLA, SDK or security programme was found, and two releases in September 2026 removed fields under `/v1` on the day they were announced.

## Before you call either

### OpenAI Realtime API

1. Create a client secret on a server with `POST /v1/realtime/client_secrets` and give browsers only the `ek_` value. Never ship the API key.
2. After a response with MCP calls finishes, send another `response.create`. The API does not create the follow-up response itself.
3. Set `truncation` with a `retention_ratio` below 1 and `token_limits.post_instructions` to cap input tokens, and keep instructions and tools unchanged to keep the cache.
4. On a WebSocket, stop playback on `input_audio_buffer.speech_started` and send `conversation.item.truncate` with `audio_end_ms`. WebRTC and SIP truncate on the server.
5. Use `gpt-realtime-2.1` or `gpt-realtime-2.1-mini`. `gpt-realtime` and `gpt-realtime-mini` shut down on 20 January 2027.

### Vocily AI

1. Send a fresh UUID in `Idempotency-Key` on every `POST /v1/calls`. The API refuses the request without it
2. Pass a `from_number` the workspace holds. The shared Test Number returns 403 from the API
3. Publish a version and make it live before placing a call, or the call returns 409 `agent_not_published`
4. Branch on `detail.code`, falling back to the top-level `code`. A 429 body is flat, so read `Retry-After`
5. Read `currency` on every call and chat record. Costs are in rupees or dollars depending on the organisation

## Questions

### Which is better for AI agents, OpenAI Realtime API or Vocily AI?

OpenAI Realtime API scores 63.3 (B) on agent readiness against Vocily AI's 53.8 (D), and leads in 3 of 7 scored categories. Vocily AI leads on schema & documentation, agent ergonomics, payments & pricing and maintenance & community.

### Do OpenAI Realtime API and Vocily AI need an API key?

Both need an API key.

### Can an agent call OpenAI Realtime API and Vocily AI without installing anything?

Yes. OpenAI Realtime API has a hosted endpoint at https://api.openai.com/v1/realtime and Vocily AI at https://api.vocily.ai.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/openai-realtime-vs-vocily.json, and with the fewest tokens: https://www.anchorterminal.com/compare/openai-realtime-vs-vocily.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "openai-realtime", "b": "vocily"}`. From a terminal: `anchor compare openai-realtime vocily`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/openai-realtime.json and https://www.anchorterminal.com/api/v1/tools/vocily.json

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