Soundverse API vs Stable Audio API

Soundverse API

Songs with vocals, instrumentals, stems (2, 6 or 12), SFX and remix behind one endpoint. No status page, changelog or security.txt.

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.

Soundverse API

1. Always set Idempotency-Key on creates, so a retry after a 429 doesn't bill twice
2. Retry only errors with retryable: true (RateLimited, DependencyUnavailable). 401 and 403 won't fix themselves
3. Pass license explicitly. The default is 1, royalty-free, which doesn't cover sync or distribution
4. Fetch audio through GET /v1/files/{file_id}/download, then poll GET /v1/generations/{id} or open /stream for progress

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