402 on a 30-second 1080p Seedance 2.5 job: you need $42.65

A wallet with $30 in it can run hundreds of cheap video jobs and still fail at the one that matters. Sume reserves the price when a video job is submitted, and if the workspace balance is below that reserve the API answers 402 insufficient_credits and creates no job. For the longest Seedance 2.5 request, 30 seconds at 1080p, the price is 1,458,000 video tokens at $0.02925 per 1,000, which is $42.65.

That figure is checked in Sume's price tests, and 16:9 and 9:16 give the same value because the pixel count is the same. At 720p the same 30 seconds is $17.33 and at 480p it is $8.06, so a wallet that is too low for the final render can still be enough for a draft.

A handler that says what to do

The script submits that request with Python's urllib and treats the two refusals differently. A 402 is a balance problem and no retry helps. A 429 is a rate limit and a later retry does. It was run against a local server that answered 402, and it printed the top-up message and exited with status 2.

import json, os, urllib.error, urllib.request

BASE = os.environ.get("SUME_API_BASE", "https://api.sume.com")
body = {"model": "seedance-2.5", "prompt": "A glacier calving at sunrise",
        "duration": 30, "resolution": "1080p", "aspect_ratio": "16:9"}
req = urllib.request.Request(
    f"{BASE}/v1/videos", data=json.dumps(body).encode(), method="POST",
    headers={"Authorization": f"Bearer {os.environ['SUME_API_KEY']}",
             "Content-Type": "application/json",
             "Idempotency-Key": "glacier-30s-1080p-0001"})
try:
    job = json.load(urllib.request.urlopen(req))
    print("accepted", job["id"])
except urllib.error.HTTPError as err:
    if err.code == 402:
        # Balance is below the reserve. For this job the reserve is about $42.65.
        print("top up the workspace by at least $42.65, then submit again")
        raise SystemExit(2)
    if err.code == 429:
        raise SystemExit("rate limited: wait, then submit again")
    raise

The errors you will meet

These codes come from the error table in Sume's video API contract.

Planning the balance

Before a big render, compute the price and compare it with the balance in your own code, so the failure is a message you wrote rather than an error from a queue worker at 3 a.m. The Idempotency-Key header makes a resend after a timeout return the original job when one was created, so retrying does not charge twice.

If the amount is hard to justify, lower one of the three levers: resolution, length or model. Moving the same 30 seconds from Seedance 2.5 at 1080p to Wan 3.0 at 1080p costs $7.50, because Wan bills $0.25 a second. They are not the same look, but the gap is a good reason to test before spending.