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MiniMax H3

MiniMax H3 · Locally verified recipe

Resume a video API task: bounded polling and verified download

A downloadable Node.js 24 client that resumes an existing public API task, handles 429 and terminal states, and saves output with a checkpoint, size limit and SHA-256. Includes 24 executed localhost fixture scenarios.

Recover a known public API task after a client restart, finish polling within a fixed budget, and save one verifiable local output without submitting another generation.

Download the practice brief

01 · Prepare the inputs

  • Install Node.js 24 and download client.mjs plus run-fixture.mjs into the same directory.
  • Choose an existing public API task ID and its owner’s API key; browser-generated tasks may be outside this endpoint’s scope.
  • Set SEEDANCE_API_KEY only in the server-side process environment, then choose a controlled output directory.
  • Verify the exact managed HTTPS media origin before allowing a delivery host different from minimaxh3.studio.

02 · Prompt and steps

  1. 01

    Run the offline contract fixture

    Execute node run-fixture.mjs first. Its server uses only 127.0.0.1 and synthetic MP4-prefix bytes. The recorded Node v24.14.0 run passed 24 scenarios; this tests client control flow, not generation or video playback.

  2. 02

    Resume the original task ID

    Run node client.mjs --task YOUR_EXISTING_API_TASK_ID --out ./saved-video. The client uses only GET /api/v1/tasks/{id}; a restart never submits a new video-generation request. Checkpoint data excludes credentials, raw responses and delivery URLs.

  3. 03

    Handle the exact public statuses

    Read the direct task object, without a data envelope. processing keeps polling; completed requires output.video_url; failed exits with the task error code. A missing or differently owned public API task returns 404 and stops.

  4. 04

    Keep retries within a finite budget

    Normal polling waits five seconds. 429 and 503 respect a bounded Retry-After or exponential fallback; all requests share a ten-minute deadline and a 120-request limit. A timeout is a reason to inspect and resume the existing task, not to replace it.

  5. 05

    Download only from a verified origin

    If required, add --media-origin https://YOUR_VERIFIED_MEDIA_HOST after checking the managed delivery origin. Download requests carry no API key and reject redirects, URL user information, unexpected hosts and non-MP4 Content-Type.

  6. 06

    Verify the local file and retain the checkpoint

    Media is streamed through an exclusive temporary file with a 256 MiB default limit. The client checks its MP4 ftyp prefix and SHA-256, refuses overwrite, and records final bytes/hash. Re-running a completed checkpoint first verifies the saved file. A real video still needs separate playback and content review.

03 · Review the result

  • The fixture passes all 24 recorded scenarios, uses only localhost GET requests, and closes its server after completion.
  • The original task ID survives restart; no POST or paid task submission is present in the client.
  • Checkpoint files contain no API key, raw task response or signed delivery URL.
  • The completed local copy matches its recorded byte count and SHA-256; partial media is removed after a rejected download.
  • 401/404, terminal failure, poll/deadline exhaustion, unapproved hosts, redirects, unsafe names/symlinks, oversize output and checksum mismatch stop without a replacement generation.

04 · Troubleshooting and ending

A valid-looking task returns not_found.

Confirm it was created by the public API and belongs to the same API key owner. Do not assume browser tasks are queryable here or generate a replacement automatically.

Polling reaches its deadline while the task is processing.

Keep the checkpoint, inspect service state, then rerun with the same task ID. Adjust --timeout-ms only within a finite operating budget.

The result URL is blocked or the saved file fails validation.

Verify the actual managed media origin, expected size and MP4 format before modifying --media-origin or --max-bytes. Supply --sha256 only with an independently trusted hash.

The task reports failed and a refund is expected.

Inspect the actual error, credits_refunded and billing_status separately. The local fixture does not verify live billing and the client neither submits another task nor executes a refund.

Ending and next step

The source-backed API contract and executed fixture establish how the client resumes, stops and saves bytes. Live credentials, provider completion, billing/refunds, video decoding and model quality remain untested; validate those with a known existing task before production integration.

Recovery and download logic was verified against a localhost fixture. No production generation was submitted and the fixture does not test model output quality.