MidJourney Integration Guide

YutoAPI MidJourney capabilities are organized under "Image Models -> MidJourney". This page explains where to start and how a complete MidJourney task usually runs.

Recommended Reading Order

1. Start with Midjourney Integration Guide to understand fast / relax modes, task types, polling, and button actions.
2. For your first image generation, use Submit Imagine Task.
3. After receiving a task ID, poll task status with Fetch Task by ID.
4. If the result contains buttons, send the selected customId and taskId to Submit Action for upscale, variation, repaint, reroll, or zoom operations.

Common Capabilities

Scenario	Endpoint	Notes
Text-to-image / image-guided image generation	/mj/submit/imagine	Main entry point for prompt-based generation with optional reference images.
Image blending	/mj/submit/blend	Blend multiple images into a new image.
Image description	/mj/submit/describe	Generate text descriptions from an image.
Prompt analysis	/mj/submit/shorten	Analyze or shorten prompts.
Button actions	/mj/submit/action	Run U, V, reroll, zoom, and related actions on an existing task.
Modal actions	/mj/submit/modal	Submit local repaint, zoom, or other actions that require modal parameters.
Task query	/mj/task/{id}/fetch	Poll task status, progress, image URL, and available buttons.

Minimal Flow

Step 1: submit an Imagine task:

curl --request POST \
  --url '{BaseURL}/mj/submit/imagine' \
  --header 'Authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{
    "base64Array": [],
    "prompt": "black cat, cinematic lighting"
  }'

The response contains a task ID, for example:

{
  "code": 1,
  "description": "Submit success",
  "result": "1320098173412546"
}

Step 2: query the result with the task ID:

curl --request GET \
  --url '{BaseURL}/mj/task/1320098173412546/fetch' \
  --header 'Authorization: Bearer YOUR_API_KEY'

When status is SUCCESS and progress is 100%, read imageUrl as the generated image. If the task fails, check failReason first.

Step 3: if you need upscale or variations, copy the target customId from the returned buttons:

curl --request POST \
  --url '{BaseURL}/mj/submit/action' \
  --header 'Authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{
    "taskId": "1320098173412546",
    "customId": "MJ::JOB::upsample::1::example"
  }'

Action endpoints also return a new task ID, which should be polled until completion.

Notes

• Write prompts with clear subject, style, composition, aspect ratio, and constraints to reduce retries.
• MidJourney tasks are asynchronous. Do not wait for the final image in the submit request; poll the query endpoint instead.
• Use progressive polling intervals such as 2 seconds, 4 seconds, then 8 seconds to avoid excessive requests.
• fast and relax modes differ in cost and speed. Choose based on your business scenario.
• Do not put API keys in public frontend code, logs, GitHub, or screenshots.