Video

Runway Gen-4.5 video

Runway Gen-4.5 — 5s/10s. 720p/1080p. Text + image-to-video.

Category: Create · runway-gen-4-5

How to use & limits

Text-to-video with an optional single reference image (image_urls, max 1).
prompt: up to 1,800 characters.
Duration: 5 or 10 seconds.
aspect_ratio: 16:9, 9:16, 4:3, 3:4, 1:1 or 21:9 (default 16:9).
Optional seed for reproducibility.

Capabilities

What this model supports, straight from the schema — no pricing, no infrastructure detail.

Capability	Value
`video_edit` Video edit	—
`text_to_video` Text-to-video	Yes
`image_to_video` Image-to-video	Yes
`reference_to_video` Reference-to-video	—

Parameters

Fields accepted in params (or first-class, where applicable) for POST /generations.

Name	Label	Type	Required	Default	Options	Min / Max	Description
`prompt`	Prompt	textarea	Required	—	—	—	Scene description; up to 1,800 characters.
`image_urls`	Image references	multi_select	Optional	—	—	— – 1	Optional reference image (max 1).
`duration`	Duration	select	Optional	5	—	—	Duration: 5 or 10 seconds (default 5).
`aspect_ratio`	Aspect ratio	select	Optional	16:9	16:9 · 9:16 · 4:3 · 3:4 · 1:1 · 21:9	—	Aspect ratio: 16:9, 9:16, 4:3, 3:4, 1:1 or 21:9.
`seed`	Seed	number	Optional	—	—	—	Optional integer seed.

Example request

bash

curl -X POST https://caranguejo.art/api/v1/dev/generations \
  -H "Authorization: Bearer $CK" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "runway-gen-4-5",
  "prompt": "A high-speed train crosses a mountainous landscape at dawn.",
  "params": {
    "duration": 5,
    "aspect_ratio": "16:9"
  }
}'

javascript

const res = await fetch("https://caranguejo.art/api/v1/dev/generations", {
  method: "POST",
  headers: {
    "Authorization": "Bearer " + process.env.CK,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "model": "runway-gen-4-5",
    "prompt": "A high-speed train crosses a mountainous landscape at dawn.",
    "params": {
      "duration": 5,
      "aspect_ratio": "16:9"
    }
  }),
});
const { data } = await res.json();

Example response

json

{
  "id": "9f0c1a7e-…",
  "object": "generation",
  "model": "runway-gen-4-5",
  "type": "video",
  "status": "completed",
  "output": {
    "assets": [
      {
        "url": "https://media.caranguejo.art/outputs/example.mp4",
        "type": "video"
      }
    ]
  }
}

The job's real cost is returned as credits_charged on the completed response — check GET /balance for the account balance.

Common errors for this job type:

`insufficient_credits`	Account balance can't cover the job cost.
`content_policy_violation`	Prompt or media rejected by content policy.
`generation_timeout`	The job exceeded the maximum processing time.
`rate_limited`	Too many requests per minute.
`invalid_input`	A required parameter is missing or outside the model's schema.
`generation_failed`	Generic processing failure.