Watermark & AIGC Labeling

Extract Image Watermark

0calls

5 credits / call

Found an image you suspect was stolen or AI-generated, and want to check whether it carries a hidden marker? Hand it straight to this endpoint and it pulls the embedded marker back out in full.

POST

uapis.cn

/api/v1/watermark/decode

Body

file

The image file to read a watermark from. PNG, JPEG, and WebP are supported.

Drag a file here, orclick to upload

The image file to read a watermark from. PNG, JPEG, and WebP are supported.

url

string

An image link that's publicly reachable.

image_base64

string

The image as Base64; the data: prefix is optional.

ecc

string

Error-correction level. Must match what was used when embedding, otherwise the payload can't be recovered.

model_type

string

Watermark profile. Must match what was used when embedding.

Overview

This endpoint detects whether an image contains an invisible watermark and, if so, recovers the original marker that was written in. It still reads back reliably in most cases even after the image has been compressed, cropped, or forwarded many times. It also guards against false positives: if the image really was never processed, it clearly returns no result instead of stitching together something meaningless.

Notes

If you changed any advanced parameters when embedding (such as ecc or model_type), you must pass the same values here when reading. If embedding used the defaults, just leave these empty.

Request body

The image to inspect. Both multipart/form-data and application/json are supported.

file

fileoptional

The image file to read a watermark from. PNG, JPEG, and WebP are supported.

url

stringoptional

An image link that's publicly reachable.

image_base64

stringoptional

The image as Base64; the data: prefix is optional.

ecc

stringoptional

Error-correction level. Must match what was used when embedding, otherwise the payload can't be recovered.

model_type

stringoptional

Watermark profile. Must match what was used when embedding.

Name	Type	Attributes	Description
`file`	file	optional	The image file to read a watermark from. PNG, JPEG, and WebP are supported.
`url`	string	optional	An image link that's publicly reachable.
`image_base64`	string	optional	The image as Base64; the data: prefix is optional.
`ecc`	string	optional	Error-correction level. Must match what was used when embedding, otherwise the payload can't be recovered.
`model_type`	string	optional	Watermark profile. Must match what was used when embedding.

Response

200 / OK

Read completed; returns the detection result.

JSON

{
  // Whether a watermark was detected.
  "present": true,
  // The recovered marker (present only when present=true).
  "payload": "a1B2c3D",
  // Decision confidence, between 0 and 1.
  "confidence": 0.99,
  // Read time, in milliseconds.
  "decode_ms": 41.2
}

400 / Bad Request

Bad request, e.g. missing image source.

JSON

{
  "code": "INVALID_PARAMETER",
  "message": "an image source is required"
}

503 / Service Unavailable

The watermark service is temporarily unavailable.

JSON

{
  "code": "SERVICE_TEMPORARILY_UNAVAILABLE",
  "message": "the watermark service is temporarily unavailable"
}

Quick start

Pick your language to see usage examples

Auth mode:

cURL command

curl -X POST 'https://uapis.cn/api/v1/watermark/decode' \
  -H 'Authorization: Bearer YOUR_API_KEY'

Frequently asked questions

Are there any special restrictions for the Extract Image Watermark API?

Extract Image Watermark follows our standard usage policy. Refer to the endpoint reference above for the exact rate limits and parameter requirements. Reach out if you have unusual needs.

Are the APIs on UAPI free to use?

UAPI gives every visitor free credits so you can call any endpoint right away. Visitor credits have a usage cap, and if you need more you can for additional credits.

Do I need to register an account to use UAPI?

No registration is required for visitor credit calls. If you need more credits or want to manage your call history, you can register a free account. Signed-in users get more free credits and can review usage details in the console.

Which languages and use cases does UAPI support?

Our APIs follow standard HTTP and RESTful design, so any language that can send network requests works — including JavaScript (Node.js, Vue, React), Python, Java, PHP, Go, C#, and more. They fit web apps, mobile backends, mini-program cloud functions, automation scripts, and similar scenarios.

Related APIs

Add Image Watermark

Want to brand your original images without spoiling how they look, or trace AIGC-generated images later on? This endpoint quietly tucks a marker of your choosing inside the image.

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Need your AI-generated images to meet national compliance requirements before they go live? One call to this endpoint automatically applies the three labels defined by GB 45438-2025.

Generate AIGC Service-Provider Code

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