Letzai API

LetzAI API Integration Skill

Overview

Helps you integrate the LetzAI public API for AI image and video generation, editing, upscaling, asset uploads, and custom model (LoRA) training. Custom-trained models for persons, objects and styles are referenced inside prompts with @modelname.

Authentication

• Base URL: https://api.letz.ai
• Auth: Authorization: Bearer YOUR_API_KEY
• Get an API key: letz.ai/subscription
• Swagger (source of truth): api.letz.ai/doc — machine-readable at /doc-json and /doc-yaml

const headers = {
  'Content-Type': 'application/json',
  Authorization: `Bearer ${process.env.LETZAI_API_KEY}`,
};

headers = {
    "Content-Type": "application/json",
    "Authorization": f"Bearer {os.environ['LETZAI_API_KEY']}",
}

Do not confuse the public API with the private one. https://api.letz.ai is the public developer API described here. https://private-api.letz.ai powers the LetzAI web app and has different route names (/upscales, /image_completions, /video-edits). Those routes 404 on the public API.

Unknown-field rejection

The API validates request bodies strictly. Sending a field that is not in the schema returns 400. In particular there is no negativePrompt, seed or aspectRatio on POST /images — aspect ratio is expressed via width/height.

Core Workflows

1. Image Generation — POST /images

Image models

mode is the resolution tier, and the accepted values are model-specific.

Aliases are accepted, e.g. gemini-3-pro-image-preview still resolves to Nano Banana Pro. The live catalogue with pricing lives at letz.ai/docs/models.json.

Workflow

1. POST /images
2. Read id from the response
3. Poll GET /images/{id} every 3 s
4. On status === "ready", read imageVersions.original

See examples/image_generation.js.

2. Video Generation — POST /videos

Image input is optional — omit all of originalImageCompletionId / imageUrl / imageUrls for pure text-to-video.

settings

Video models

Use the `video-` prefixed key as settings.mode.

Workflow

1. POST /videos
2. Poll GET /videos/{id} every 2–3 s
3. On status === "ready", read videoVersions.original

See examples/video_generation.py.

3. Image Editing — POST /image-edits

settings:

• resolution: "2k" (HD) or "4k" (Ultra HD)
• aspect_ratio: "1:1", "16:9", "9:16", "4:3", "3:4", "21:9", "9:21"
• model: same identifiers as baseModel

Provide at least one source: imageUrl, inputImageUrls, originalImageCompletionId or originalImageCompletionIds.

Prefer the top-level `baseModel`. Server-side queue routing reads baseModel; settings.model is forwarded to the worker. Setting both to the same value is safest.

Workflow

1. POST /image-edits
2. Poll GET /image-edits/{id} every 3 s
3. On status === "ready", read generatedImageCompletion.imageVersions.original

mode: "in" (inpainting) and mode: "out" (outpainting) are deprecated — use context.

4. Upscaling — POST /upscale

The public route is `/upscale` (singular). /upscales is the private web-app route and returns 404 here.