402 insufficient_credits on a 30-second 1080p video: balance needed

A 30-second Seedance 2.5 clip at 1080p needs about $42.65 of spendable balance before Sume accepts it (30 x $1.42155 = $42.6465). If the balance is lower, the submit call fails with 402 insufficient_credits before any provider work starts, and nothing is charged.

Why the whole amount is needed up front

Sume uses queue-first admission for paid work. A valid request is accepted only if Sume can reserve the estimated cost from the workspace balance. The reservation is captured when the job succeeds. This means the balance you need is the full price of the job, not a deposit. It also means that several jobs in flight each hold their own reservation, so ten queued jobs hold ten times the amount.

What to do on a 402

The admission docs give the client behavior: upgrade the plan or wait for included Gen$, or submit a less expensive request. A less expensive request is easy to compute because price is linear in duration. With a balance of $20, the same Seedance 2.5 1080p clip fits for floor(20 / 1.42155) = 14 seconds ($19.9017). At 720p the clip that fits is floor(20 / 0.5778) = 34 seconds, so the full 30 seconds fits at $17.334.

Do not retry the identical request in a loop. A 402 is deterministic until the balance changes.

• Read the balance with GET /v1/balance before a batch.
• Keep the generation_limits snapshot from submit responses to see how many jobs are in flight.
• Dropping resolution is the largest lever: 1080p to 720p on Seedance 2.5 cuts the price by 59 percent.

Two jobs at once

Reservations stack. If you submit two 30-second Seedance 2.5 1080p jobs back to back, the second needs another $42.6465, so a balance of $60 accepts the first and refuses the second with 402, even though $60 is more than one job. A balance of $90 accepts both ($85.293) and leaves $4.707.

For Wan 3.0 at 1080p the same two jobs reserve 2 x $7.50 = $15.00. If you are batching, divide the spendable balance by the per-job reserve and round down to get the number of jobs you can have open, then compare that with your plan's accepted capacity. The smaller of the two is your real ceiling.

Sources

See errors and rate limits for the 402 row and generation admission for the reservation rules.