Per-key concurrency
2026-03-30 · Using the API
32 solves in flight and 256 unfinished submitted tasks are the default caps.
Each API key may have 32 synchronous solves running at once. The 33rd gets 429 and Retry-After. Submitted tasks that have not finished count toward a second cap, 256.
Spread load across a short queue instead of firing 1,000 threads. The model is fast. The cap is there so one key cannot crowd out the process.
A batch of 256 images is one HTTP call, not 256 concurrent calls. Prefer that when you already hold the images.
Two keys on one account do not share the in-flight counter. They do share the credit balance. A 402 on one key means the account is empty, not that the other key still has a private wallet.
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