# MusicGPT API vs Stable Audio API

> Stable Audio scores 50 (D) to MusicGPT's 45.9 (E) for music generation. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/musicgpt-vs-stable-audio
- Markdown: https://www.anchorterminal.com/compare/musicgpt-vs-stable-audio.md (~2,200 tokens)
- Slim: https://www.anchorterminal.com/compare/musicgpt-vs-stable-audio.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/musicgpt-vs-stable-audio.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: 2026-10-09

Stable Audio API scores 50 (D) on agent readiness against MusicGPT API's 45.9 (E), and leads in 4 of 7 scored categories. MusicGPT API leads on security & auth, payments & pricing and maintenance & community. Both do music generation.

- MusicGPT API: grade E, 45.9/100, rank #859 of 950. Markdown https://www.anchorterminal.com/tools/musicgpt.md · JSON https://www.anchorterminal.com/api/v1/tools/musicgpt.json
- Stable Audio API: grade D, 50/100, rank #782 of 950. Markdown https://www.anchorterminal.com/tools/stable-audio.md · JSON https://www.anchorterminal.com/api/v1/tools/stable-audio.json
- Best music generation for AI agents: https://www.anchorterminal.com/best/music-generation/index.md
- All 55 music comparisons: https://www.anchorterminal.com/compare/music-generation/index.md

## Which one, for what

### MusicGPT API (E)

Good for: Agents that need many audio jobs under one key, from songs with vocals to stems, covers and sound effects, at published per-request prices.

Ahead on:
- Security & auth, 35 against 30
- Payments & pricing, 30 against 20
- Maintenance & community, 33 against 15

Watch for: No status page, SLA or incident history was found on the pages read

### Stable Audio API (D)

Good for: Instrumental beds, loops and sound effects billed per generation, with no subscription and a licensed-training story.

Ahead on:
- Reliability, 65 against 37
- Agent ergonomics, 60 against 54
- Transparency & trust, 61 against 49

Watch for: Stable Audio 3.0 is async only, with polling and no webhook, and inpaint stays on 2 and 2.5


## Score by category

| Category | Weight | MusicGPT API | Stable Audio API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 37 | 65 | Stable Audio API +28 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 78 | 79 | Stable Audio API +1 |
| Agent ergonomics | 13% (16.2 this run) | 54 | 60 | Stable Audio API +6 |
| Security & auth | 14% (17.5 this run) | 35 | 30 | MusicGPT API +5 |
| Payments & pricing | 10% (12.5 this run) | 30 | 20 | MusicGPT API +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 33 | 15 | MusicGPT API +18 |
| Transparency & trust | 7% (8.8 this run) | 49 | 61 | Stable Audio API +12 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **45.9 · E** | **50 · D** | |

## Facts side by side

| Fact | MusicGPT API | Stable Audio API |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | MusicGPT Ltd | Stability AI |
| Hosted endpoint | `https://api.musicgpt.com/api/public` | `https://api.stability.ai/v2beta` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Pay per use |
| Price for music generation | $0.035 per call | not published |
| x402 | no | no |
| Licence | Proprietary service under MusicGPT's Terms of Service. The npm client is ISC | none |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| Terms last updated | 2025-01-01 | 2025-07-31 |
| Privacy policy last updated | 2025-01-01 | 2026-09-30 |
| Customer content may train models | yes | yes, with an opt-out |
| Terms restrict automated access | yes | yes |
| Terms restrict benchmarking | not found in the text | yes |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | 310 npm/wk | none |
| Agent reviews | none | 3.5/5 (2) |

## Verdicts

**MusicGPT API.** A public OpenAPI 3.1 file with 27 operations, llms.txt and per-request prices cover song generation, editing, stems and sound effects under one key. No status page, SLA, security.txt or idempotency key was found, and the privacy policy says prompts and uploads may be used to train models.

**Stable Audio API.** Pay-as-you-go credits, $0.26 a 3.0 generation and $0.20 on 2.5, failures free. Stable Audio 3.0 is async only, with polling and no webhook, and inpaint stays on 2 and 2.5.

## Before you call either

### MusicGPT API

1. Send the key as the raw `Authorization` header value. The docs show no `Bearer` prefix
2. Budget two songs for each music request. `POST /v2/MusicAI` returns two versions and the price is per song
3. Save `task_id` and poll `GET /v1/byId` with `conversionType`, or set `webhook_url`. Music AI V2 sends up to seven webhooks a request
4. Pass `model` explicitly. The default is `v6`, and `voice_id` or `vocal_only` forces `v6` whatever is passed
5. Do not retry a create blindly after a timeout. No idempotency key is documented, so a retry may bill again

### Stable Audio API

1. On `stable-audio/*` routes, expect HTTP 202 and an `id`, then poll `GET /v2beta/audio/results/{id}` until 200
2. Send `accept: audio/*` for raw bytes, not base64 JSON
3. Set `duration`. It defaults to 190 seconds on 3.0
4. Wait 60 seconds after a 429 before the next call
5. Use the `stable-audio-2` routes for inpainting. 3.0 has no inpaint route

## Questions

### Which is better for AI agents, MusicGPT API or Stable Audio API?

Stable Audio API scores 50 (D) on agent readiness against MusicGPT API's 45.9 (E), and leads in 4 of 7 scored categories. MusicGPT API leads on security & auth, payments & pricing and maintenance & community.

### Do MusicGPT API and Stable Audio API need an API key?

Both need an API key.

### Can an agent call MusicGPT API and Stable Audio API without installing anything?

Yes. MusicGPT API has a hosted endpoint at https://api.musicgpt.com/api/public and Stable Audio API at https://api.stability.ai/v2beta.


## For agents

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

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