API Endpoints

Changelog

Developer updates

API changelog

Follow shipped API capabilities, compatibility notes, and any action required for your integration.

Latest update

Sep 17, 2026

Release history

6 updates
  1. Changed
    Backward compatiblePOST /v2/generate · /v2/extend · /v2/upload-cover/generateAll models

    Rejected requests return 422 or 500 and are refunded immediately

    The create endpoints now report validation rejections synchronously and refund the credits, instead of returning 200 with a task that never completes.

    What changed

    • 422 means a request parameter was rejected during validation; the message names the field to fix (for example title or extensionStartTime).
    • 500 means a temporary failure; retry later.
    • Both responses include data.task_id, data.refunded and workId, and the task is marked FAILED.
    • Tasks that fail after being accepted, including extensions, are marked FAILED with a fail_message and their credits are refunded automatically.
    • Previously such requests returned 200 and the task stayed IN_PROGRESS indefinitely.

    Integration impact

    Handle 422 by fixing the listed parameter and 500 by retrying later. Both responses include data.refunded.

    View endpoint docs
  2. Changed
    Backward compatiblePOST /v2/extendAll models

    Extend requests normalise text and start time instead of failing

    POST /v2/extend now truncates over-long Custom Mode text and clamps extensionStartTime so submissions are never rejected for these fields.

    What changed

    • title is limited to 80 characters; longer values are truncated.
    • prompt is limited to 5000 characters and style to 1000; longer values are truncated.
    • extensionStartTime is clamped to 1 … (source duration - 1) seconds; missing or invalid values use the end of the source track.
    • Extensions are billed at the original track's model price and produced by chirp-v6 (chirp-v5 / chirp-v5-5 tracks) or chirp-v6-mini (older legacy tracks).

    Integration impact

    This update is backward compatible. Keep titles within 80 characters to avoid truncation.

    View endpoint docs
  3. Changed
    Backward compatiblePOST /v2/generate · /v2/extend · /v2/upload-cover/generatechirp-v3-5 … chirp-v5-5

    Legacy chirp-v3-5 to chirp-v5-5 identifiers are served by the chirp-v6 family

    Requests that still send a retired model identifier keep working and keep their historical price.

    What changed

    • chirp-v5 and chirp-v5-5 (12 credits) are served by chirp-v6.
    • chirp-v3-5, chirp-v4-0, chirp-v4-5, chirp-v4-5-plus and chirp-v4-5-all are served by chirp-v6-mini.
    • Each legacy identifier is still billed at its historical price (5, 8, 10 or 12 credits).
    • model_name in status, feed and callback results now always reports the public model that produced the audio, for example chirp-v6-mini.
    • When the model field is omitted the request is billed at the 5-credit base tier and served by chirp-v6-mini.

    Integration impact

    No change is required. Update the model field to chirp-v6 or chirp-v6-mini when convenient.

    View endpoint docs
  4. Added
    Backward compatiblePOST /v2/generate · /v2/upload-cover/generatechirp-v6 · chirp-v6-mini · chirp-v6-wild

    chirp-v6, chirp-v6-mini and chirp-v6-wild models

    The current model lineup is now the chirp-v6 family, available on generate, upload-cover and extend.

    What changed

    • chirp-v6 is the flagship model, chirp-v6-mini is the fast and economical tier, chirp-v6-wild is the more experimental variant.
    • chirp-v6 and chirp-v6-wild cost 12 credits per request, chirp-v6-mini costs 10.
    • Text limits are the same for every model: custom prompt 5000, inspiration prompt 3000, style 1000, title 80 (100 for upload-cover). Longer input is truncated instead of rejected.
    • Extensions of a chirp-v6 track use the same model; the duration field is forwarded for Custom Mode generate requests.

    Integration impact

    This update is backward compatible. Switch new integrations to chirp-v6-mini or chirp-v6.

    View endpoint docs
  5. Added
    Backward compatiblePOST /v2/generate · /v2/upload-cover/generatechirp-v6 family

    Image to Music with image_urls

    POST /v2/generate and POST /v2/upload-cover/generate now accept reference images that shape the mood of the generated track.

    What changed

    • Send image_urls as an array of up to 5 publicly accessible image URLs.
    • JPEG, JPG, PNG and WEBP are supported, up to 10MB per image.
    • Images apply to Inspiration Mode (generate) and non-custom mode (upload-cover) only; they are silently ignored in Custom Mode.
    • Image input adds 1 credit per request on top of the model price.
    • A text prompt is optional when images are provided; combine both to steer the result.

    Integration impact

    This update is backward compatible. Add image_urls only when you want images to influence the result.

    View endpoint docs
  6. Added
    Backward compatiblePOST /v2/generatechirp-v5-5

    Custom duration control for chirp-v5-5

    Custom Mode requests can now specify a target track length when using chirp-v5-5.

    What changed

    • The duration field is available only for chirp-v5-5 in Custom Mode.
    • Send a number from 10 to 360 seconds.
    • Missing or invalid values use 20 seconds.
    • Other models and Inspiration Mode ignore this field.

    Integration impact

    This update is backward compatible. Existing requests continue to work without changes.

    View endpoint docs