p-watermark

Check whether content carries a Pruna watermark and signed Content Credentials

p-watermark checks a file for the two marks Pruna adds to the content it generates:

an invisible watermark, which survives common edits such as resizing and re-compression;
a C2PA Content Credential, signed metadata that records the content as AI-generated by Pruna.

It returns what it found for each mark and a one-line verdict.

Rate Limit: 30 requests per minute

Category: Watermark Detection

Pricing: Free

Quickstart

Upload the file to check

curl -X POST "https://api.pruna.ai/v1/files" \
  -H "apikey: YOUR_API_KEY" \
  -F "content=@/path/to/your/file"

Check it

curl -X POST 'https://api.pruna.ai/v1/predictions' \
  -H 'Content-Type: application/json' \
  -H 'apikey: YOUR_API_KEY' \
  -H 'Model: p-watermark' \
  -H 'Try-Sync: true' \
  -d '{
    "input": {
      "media": "https://api.pruna.ai/v1/files/fqadqq42xq"
    }
  }'

Without Try-Sync, the request returns a prediction ID to poll, like any other model.

Parameters

Required Parameters

Parameter	Type	Description
media	string (URI)	The file to check. Accepts the formats Pruna models output (JPEG, PNG, WebP, MP4, MOV, WebM).

Output

Field	Type	Description
watermark_detected	boolean	Whether the invisible Pruna watermark was found
bit_accuracy	number	Share of watermark bits recovered, from 0 to 1
p_value	number	Chance of this match on unmarked content; lower is stronger evidence
c2pa_present	boolean	Whether the file carries a C2PA Content Credential
c2pa_valid	boolean or null	Whether that credential's signature checks out; null when there is none
c2pa_signer	string or null	Who signed the credential
verdict	string	One-line summary of the result

Verdicts

Verdict starts with	Meaning
`Verified Pruna content`	A valid Content Credential signed by Pruna was found
`Expired Pruna signature`	Pruna signed the credential, but its certificate has expired
`Pruna watermark detected`	The watermark was found, but no valid Pruna credential (for example, the metadata was stripped)
`AI-generated`	A valid credential marks the content as AI-generated, signed by someone other than Pruna
`no Pruna mark found`	Neither mark was found

The watermark on its own does not prove that Pruna generated the content. Only a valid Pruna-signed Content Credential does.

Limits

Very large files may not be checked for the watermark.
Re-saving a file usually keeps the watermark but drops the Content Credential.