Veo 3.1 · API

Quick start

Three steps: submit a job, poll it, take the video link. Replace YOUR_API_KEY with your key and the commands below run as they are.

Step 1 · Submit (returns a job id at once, HTTP 202)

curl https://kovapi.com/v1/videos/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "veo-3.1", "prompt": "A cat surfs a wave at sunset, the sea glittering gold, the camera tracking from the side", "resolution": "720p", "size": "16:9"}'

Response (HTTP 202)

{
  "id": "img_5c2e8f1a9b3d7e6f0a4c8b2d",
  "object": "video.generation.job",
  "status": "queued",
  "created": 1791281400,
  "model": "veo-3.1"
}

Step 2 · Poll every 5–10 seconds until status is succeeded or failed

curl https://kovapi.com/v1/videos/jobs/img_5c2e8f1a9b3d7e6f0a4c8b2d \
  -H "Authorization: Bearer YOUR_API_KEY"

Response when it succeeds

{
  "id": "img_5c2e8f1a9b3d7e6f0a4c8b2d",
  "object": "video.generation.job",
  "status": "succeeded",
  "created": 1791281400,
  "model": "veo-3.1",
  "data": [
    {"url": "https://img.kovapi.com/i/8c1f0e5d2b7a49e3a6d0c4f1b9e2a7d5.mp4"}
  ],
  "usage": {"clips": 1, "model": "veo-3.1"}
}

Step 3 · data[0].url is the clip (MP4). It is kept for 15 days; download it to your own storage to keep it longer.

Complete example (Python: submit, wait, save to disk)

import time
import requests

BASE = "https://kovapi.com/v1"
HEADERS = {"Authorization": "Bearer YOUR_API_KEY"}

# 1. submit
job = requests.post(f"{BASE}/videos/generations", headers=HEADERS, json={
    "model": "veo-3.1",
    "prompt": "A cat surfs a wave at sunset, the sea glittering gold, the camera tracking from the side",
    "resolution": "720p",
    "size": "16:9",
}).json()
if "error" in job:
    raise SystemExit(job["error"]["message"])

# 2. poll every 10 seconds, for up to an hour
deadline = time.time() + 3600
while job["status"] not in ("succeeded", "failed") and time.time() < deadline:
    time.sleep(10)
    job = requests.get(f"{BASE}/videos/jobs/{job['id']}", headers=HEADERS).json()

# 3. download the video
if job["status"] == "succeeded":
    url = job["data"][0]["url"]
    with open("veo-3.1.mp4", "wb") as f:
        f.write(requests.get(url).content)
    print("saved", url)
elif job["status"] == "failed":
    print("failed:", job["error"]["code"], job["error"]["message"])
else:
    print("still", job["status"], job["id"])

While queued, the poll also returns queue_position (jobs ahead of yours) and eta_seconds (expected wait). If your time limit passes, do not resubmit: the job is still there, so keep polling the same id later.

Authentication

Authorization: Bearer YOUR_API_KEY
Content-Type: application/json

Create an API Key in the console to start.

At a glance

Request parameters

The JSON body of POST /v1/videos/generations:

Other fields (seed, negative_prompt, fps, watermark and the like) are not passed on and do not change the price; results are always MP4, returned as a url.

Price

Billed per clip: one price per clip whatever its length; only the resolution can change it. Held at submit, refunded in full on failure. 1 credit = $0.005.

Reference material

• No image is text-to-video; one image is the first frame; two are first + last frame (720p only); three images, or 1–3 with image_role: reference, are references: their people or style appear in the clip without being a frame.
• No reference video or audio. Every clip is 8 seconds with sound.
• You can refer to an image in the prompt as @Image1.
• Each image is a public image URL, a data: URI or base64, up to 16 MB; send several as an array in images. We store the images before the job is queued; one that cannot be read is refused with 400, message says which, and nothing is charged.
• Reference files we store are kept for 7 days; results for 15 days.

First + last frame (720p)

curl https://kovapi.com/v1/videos/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "veo-3.1", "prompt": "A flower bud slowly opens in front of the camera", "images": ["https://example.com/first.png", "https://example.com/last.png"], "resolution": "720p", "size": "16:9"}'

The two images become the first and last frame; 720p only. To use 1–3 images as references, add "image_role": "reference".

Job status and fields

GET /v1/videos/jobs/{id} reports these statuses; every field is described in Async jobs. Poll every 5–10 seconds, or let a webhook (below) push the result. Polling is free, and any key of the same account can read the job.

• processing can go back to queued, for example while the service is busy, while a finished clip is fetched again, or after a restart. If a job cannot be finished, the gateway may render it again automatically; however many retries it takes, a job is charged once.
• One account runs up to 50 jobs at a time; further jobs wait in submission order, and a job that has not started after 15 minutes fails and is refunded in full. Job records are kept for 3 days and video links for 15 days.

How long it takes

Usually 1–3 minutes.

Errors and refunds

An error at submit comes back at once as HTTP 4xx / 5xx: no job is created and nothing is charged. A failure after the job was accepted is reported by the job endpoint, and the hold is refunded in full. Every code is listed under Error codes.

Errors at submit

Failed jobs (status failed)

Branch on code, not on the text of message. Treat any code you do not recognise (or a missing one) as upstream_error: resubmitting usually works. Every failed job is refunded in full.

Webhooks instead of polling

Add callback_url when you submit and the moment the job ends, success or failure, the gateway pushes exactly what the poll endpoint returns to that URL, signed and retried on failure. You can also set an account-wide address under Settings → Webhook in the console. Webhook docs →

curl https://kovapi.com/v1/videos/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "veo-3.1", "prompt": "A cat surfs a wave at sunset, the sea glittering gold, the camera tracking from the side", "resolution": "720p", "size": "16:9", "callback_url": "https://your-domain.com/webhook"}'