HappyHorse 1.0
Animate one or more images into a 3–15 second video at 720p or 1080p. An image is required.
- Asynchronous: the create call returns a task ID; the video arrives when the task succeeds.
- Image to video only:
imagesis required (1 to 9 links). There is no text-to-video mode. - Clips of 3 to 15 seconds;
durationis a whole number of seconds. - Billed by the resolution and the number of seconds you request. A failed task costs nothing.
HappyHorse 1.0 is not in the live model list (GET /v1/media/models) at the time of writing. Until it is listed, a create request for it is refused with 503 processing_unavailable. Check the list before you build on it.
Opens this model in the API Explorer. Enter your BeatAPI API key to create a task: the call is real and is billed to your own balance.
Model IDs
Two HappyHorse models share this endpoint and accept exactly the same request. The values below come straight from the gateway contract.
Endpoint and authentication
POST https://api.beatapi.io/v1/videos/tasks
Authorization
string
Required
Your BeatAPI API key, sent as Bearer <BEATAPI_API_KEY>. Create keys in the Dashboard. Keep keys on your server; never ship them in a browser or mobile app.
Send the body as JSON with Content-Type: application/json. Idempotency-Key is optional: send a unique value (at most 255 characters) per logical request and reuse it only to retry that exact body. Within 24 hours a retry with the same key and body returns the first response again with Idempotent-Replayed: true; the same key with a different body returns 409 idempotency_conflict. Responses other than 2xx are not stored, so a retry after a 400 or 402 runs again.
How a request works
Create the task
POST the parameters below to the endpoint. A 201 means the task was accepted and its price reserved from your balance; the work runs in the background. Save data.id.
Wait for it to finish
Call GET /v1/tasks/{task_id} and wait data.poll_after_seconds between calls (5 s for images, 8 s for videos) until status is succeeded or failed. Or register a webhook for task.succeeded and task.failed; keep polling as the fallback, because a task stopped by the processing timeout sends no event.
Save the result
On succeeded, download every data.output.media[].url and store the files you need; BeatAPI does not promise how long result URLs stay available. On failed, read data.error_code and data.error_message: the reserved amount was returned to your balance, and data.retryable says whether sending the same request again can succeed.
Input modes
Request parameters
model
string
Required
The model to run.
Value: happyhorse-1.0
If the value is wrong
- Missing:
"model" is required - An image model sent to this endpoint:
"model" nano-banana-2 is served by POST /v1/images/tasks, not this endpoint
prompt
string
Required
What happens in the video: the motion, the expression and the camera.
Length: 1–5000 characters
- Length is counted in characters (a CJK character counts as one).
If the value is wrong
- Missing:
"prompt" is required - Empty or longer than the limit:
"prompt" has an unsupported length - Not a string:
"prompt" must be a string
images
string[]
Required
The picture to animate, or several pictures in the order you want them used. Required.
Items: 1–9
Each item is a public https:// URL. For a local file, upload it first with POST /v1/files and pass the returned data.url.
- Each link must be a public
https://URL. The gateway does not download or measure the files when the task is created. - This model has no text-to-video mode: a request without
imagesis refused. aspect_ratioandresolutionkeep their defaults (16:9,720p) when you leave them out, because the gateway does not read them from the image. Send the shape you want.
If the value is wrong
- Missing:
"images" is required - More than 9 links:
"images" accepts at most 9 items - Empty array:
"images" requires at least 1 item - Not an array:
"images" must be an array - Not an https:// link:
"images[0]" must be a public HTTPS URL
duration
integer
OptionalDefault: 5
Length of the video in seconds, a whole number.
Default: 5
Range: 3–15
- If you leave it out,
5is used and billed. - Seconds are billed (see Billing), so this is the main lever on the price.
If the value is wrong
- Outside 3–15, not a whole number, or sent as a string:
"duration" is outside its supported range
aspect_ratio
string
OptionalDefault: 16:9
Shape of the video as width:height.
Allowed values: 16:9, 9:16, 1:1, 4:3, 3:4
Default: 16:9
- If you leave it out,
16:9is used, also when the image is portrait. adaptiveis not offered by this model.
If the value is wrong
- A value not in the list:
"aspect_ratio" must be one of: [16:9 9:16 1:1 4:3 3:4]
resolution
string
OptionalDefault: 720p
Output resolution. 1080p costs more per second than 720p.
Allowed values: 720p, 1080p
Default: 720p
- Lower case only.
If the value is wrong
- A value not in the list (for example
480por720P):"resolution" must be one of: [720p 1080p]
Input media limits
The gateway reads every input before the task is created and refuses one outside these limits with a 400 bad_request that names the input. Nothing is charged.
- The gateway does not read your image files when it creates the task, so no size, resolution or format limit is checked for this model; only the field rules above apply.
- A link the model cannot fetch or use fails the task after it was created, usually with
bad_request(orcontent_policy_violationwhen moderation refuses an input), and the task is refunded in full. - Have a local file? Upload it with
POST /v1/files(png, jpg, jpeg or webp; up to 50 MB) and pass the returneddata.url.
Fields this model does not accept
Sending one of these is refused before anything is charged, instead of being ignored:
reference_images,reference_videos,reference_audios,generate_audio,seed,quality,sound,task_type,output_format,watermarkand the other fields of other video models →field "reference_videos" is not supported by model happyhorse-1.0(with the field you sent). Put pictures inimages.- Any field the video endpoint does not know at all →
unknown field: <name>.
Request examples
Image to video
A 5-second 720p portrait clip made from one image.
Several images
Two images, passed to the model in list order, as a 10-second 1080p clip.
Responses
Create a task (201)
The task object. output is null until the task succeeds. Fields marked “while running” disappear once the task finishes.
Finished task
GET /v1/tasks/{task_id} returns HTTP 200 with status: "succeeded" and the result in data.output.
Output fields
Failed task
A failed task is still HTTP 200 on GET /v1/tasks/{task_id}: the failure is in the body. The reservation is returned in full, so nothing is charged.
Complete example
Create a task, wait for it with the server’s polling hint, and print the result URLs. Set BEATAPI_API_KEY in your environment and install requests.
Billing
- These prices apply once the model is listed; until then a create request is refused and nothing is charged.
- The price follows the resolution and the number of seconds you request (
duration, 5 if you leave it out). 1080p costs more per second than 720p.aspect_ratioand the number of images do not change it. - The table below shows 8-second clips; other lengths are priced per second at the same rate for their resolution.
- The price is reserved when the task is created;
data.usage.billable_duration_secondsshows the seconds it is based on. - A failed task, including one refused by moderation after submission, is refunded in full.
Current list prices, the same as on Pricing. An account with a negotiated discount pays less; data.usage on the task always shows the amount actually charged.
Common errors
HTTP errors at a glance
Errors before a task exists arrive as a non-2xx response, and nothing is charged. Branch on error.code or error.retryable; message names the problem. The full list and retry policy are on Errors.
Authentication
Send your API key as Authorization: Bearer <BEATAPI_API_KEY>.
Headers
Send the body as JSON with Content-Type: application/json. Idempotency-Key is optional: send a unique value (at most 255 characters) per logical request and reuse it only to retry that exact body. Within 24 hours a retry with the same key and body returns the first response again with Idempotent-Replayed: true; the same key with a different body returns 409 idempotency_conflict. Responses other than 2xx are not stored, so a retry after a 400 or 402 runs again.
Request
The picture to animate, or several pictures in the order you want them used. Required.
Items: 1–9
Each item is a public https:// URL. For a local file, upload it first with POST /v1/files and pass the returned data.url.
- Each link must be a public
https://URL. The gateway does not download or measure the files when the task is created. - This model has no text-to-video mode: a request without
imagesis refused. aspect_ratioandresolutionkeep their defaults (16:9,720p) when you leave them out, because the gateway does not read them from the image. Send the shape you want.
If the value is wrong
- Missing:
"images" is required - More than 9 links:
"images" accepts at most 9 items - Empty array:
"images" requires at least 1 item - Not an array:
"images" must be an array - Not an https:// link:
"images[0]" must be a public HTTPS URL
The model to run.
Value: happyhorse-1.0
If the value is wrong
- Missing:
"model" is required - An image model sent to this endpoint:
"model" nano-banana-2 is served by POST /v1/images/tasks, not this endpoint
What happens in the video: the motion, the expression and the camera.
Length: 1–5000 characters
- Length is counted in characters (a CJK character counts as one).
If the value is wrong
- Missing:
"prompt" is required - Empty or longer than the limit:
"prompt" has an unsupported length - Not a string:
"prompt" must be a string
Shape of the video as width:height.
Allowed values: 16:9, 9:16, 1:1, 4:3, 3:4
Default: 16:9
- If you leave it out,
16:9is used, also when the image is portrait. adaptiveis not offered by this model.
If the value is wrong
- A value not in the list:
"aspect_ratio" must be one of: [16:9 9:16 1:1 4:3 3:4]
Length of the video in seconds, a whole number.
Default: 5
Range: 3–15
- If you leave it out,
5is used and billed. - Seconds are billed (see Billing), so this is the main lever on the price.
If the value is wrong
- Outside 3–15, not a whole number, or sent as a string:
"duration" is outside its supported range
Output resolution. 1080p costs more per second than 720p.
Allowed values: 720p, 1080p
Default: 720p
- Lower case only.
If the value is wrong
- A value not in the list (for example
480por720P):"resolution" must be one of: [720p 1080p]
Response
The task object. output is null until the task succeeds. Fields marked “while running” disappear once the task finishes.

