CamScanner Add Watermark

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name: camscanner-watermark-image description: Use CamScanner to add a tiled text watermark across an entire image. Triggers on "add watermark to image", "watermark image", "add copyright text to image", "stamp image with text", or when the user wants to overlay repeating text (e.g. "Confidential", "Draft", copyright notices) on an image. Supports custom color, opacity, and font size. metadata: author: CamScanner version: "1.0" openclaw: emoji: "💧" requires: bins: ["curl", "jq"] homepage: "https://www.camscanner.com"

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CamScanner Watermark Image

Overview

CamScanner applies a full-page tiled text watermark to an image. The watermark text is repeated in a diagonal grid pattern across the entire image. The workflow is a 3-step pipeline: upload the image, apply watermark, then download the result.

When to Use

User wants to add a text watermark to an image

User needs to stamp "Confidential", "Draft", "Copyright", etc. on an image

User wants repeating diagonal text overlay on a photo

Privacy & Data

> Important: Privacy & Data Flow Notice > > - Third-party service: This skill sends your files to CamScanner's official servers (ai-tools.camscanner.com) for processing. > - Data retention: CamScanner servers process your files in real-time. Files are not permanently stored on the server. > - Local files: Output files are saved to your local filesystem at the path you specify.

API Reference

Base URL: https://ai-tools.camscanner.com

Parameters

| Parameter | Required | Type | Default | Description | | --------- | -------- | ---- | ------- | ----------- | | file_id | Yes | string | — | Uploaded image file_id | | text | Yes | string | — | Watermark text (max 200 chars) | | color | No | string | #000000 | Hex color, e.g. #FF0000 for red | | opacity | No | number | 0.4 | Transparency 0-1 (0=invisible, 1=opaque) | | size | No | integer | 36 | Font size 1-200 |

Do NOT pass mode, x, y, width, height, or rotation — these are fixed internally for tiled watermark layout.

Step 1: Upload Image

BASE="https://ai-tools.camscanner.com"
IN_FILE_ID=$(curl -sS -X POST "$BASE/v1/tools/upload_file/execute" \
  -H "Content-Type: application/octet-stream" \
  --data-binary "@/path/to/image.jpg" | jq -r '.tool_result.data.file_id')

Response:

{
  "code": 200,
  "tool": "upload_file",
  "tool_result": {
    "success": true,
    "data": {
      "file_id": "file_1741857600_ab12cd34ef56",
      "size": 24576
    }
  }
}

Step 2: Apply Watermark

Minimal call (recommended — uses sensible defaults):

OUT_FILE_ID=$(curl -sS -X POST "$BASE/v1/tools/watermark_image/execute" \
  -H "Content-Type: application/json" \
  -d "{\"file_id\":\"$IN_FILE_ID\",\"text\":\"Copyright 2026\",\"output_mode\":\"file_id\"}" \
  | jq -r '.tool_result.data.file_id')

With custom styling (only add fields the user explicitly requests):

OUT_FILE_ID=$(curl -sS -X POST "$BASE/v1/tools/watermark_image/execute" \
  -H "Content-Type: application/json" \
  -d "{\"file_id\":\"$IN_FILE_ID\",\"text\":\"Confidential\",\"color\":\"#FF0000\",\"opacity\":0.5,\"size\":60,\"output_mode\":\"file_id\"}" \
  | jq -r '.tool_result.data.file_id')

Response:

{
  "code": 200,
  "tool": "watermark_image",
  "tool_result": {
    "success": true,
    "data": {
      "file_id": "file_1741857701_9988aabbccdd.jpg",
      "target_type": ""
    },
    "metadata": {
      "engine": "imageprocess"
    }
  }
}

Step 3: Download Result

curl -sS -X POST "$BASE/v1/tools/download_file/execute?response_mode=raw" \
  -H "Content-Type: application/json" \
  -d "{\"file_id\":\"$OUT_FILE_ID\"}" \
  -o /path/to/watermarked.jpg

Critical: The response_mode=raw query parameter is required to get the binary file. Without it, the response is JSON.

Quick Reference: Complete Pipeline

BASE="https://ai-tools.camscanner.com"
INPUT_IMAGE="/path/to/image.jpg"
TEXT="Copyright 2026"
OUTPUT_FILE="/path/to/watermarked.jpg"
Upload
IN_FILE_ID=$(curl -sS -X POST "$BASE/v1/tools/upload_file/execute" \
  -H "Content-Type: application/octet-stream" \
  --data-binary "@$INPUT_IMAGE" | jq -r '.tool_result.data.file_id')
Watermark
OUT_FILE_ID=$(curl -sS -X POST "$BASE/v1/tools/watermark_image/execute" \
  -H "Content-Type: application/json" \
  -d "{\"file_id\":\"$IN_FILE_ID\",\"text\":\"$TEXT\",\"output_mode\":\"file_id\"}" \
  | jq -r '.tool_result.data.file_id')
Download
curl -sS -X POST "$BASE/v1/tools/download_file/execute?response_mode=raw" \
  -H "Content-Type: application/json" \
  -d "{\"file_id\":\"$OUT_FILE_ID\"}" \
  -o "$OUTPUT_FILE"

Common Mistakes

| Mistake | Fix | | ------- | --- | | Forgetting response_mode=raw on download | Always append ?response_mode=raw to the download URL | | Missing text parameter | text is required — ask the user what text to use | | Passing internal params like mode, x, y | Never pass these — they are fixed for tiled layout | | Color without # prefix | Both FF0000 and #FF0000 work, but always use 6 hex digits | | RGBA PNG input (4-channel with alpha) | May cause 500 error from upstream — convert to JPEG first if this happens | | Wrong Content-Type on upload | Upload uses application/octet-stream, not multipart/form-data |

Error Handling

# After upload
if [ -z "$IN_FILE_ID" ] || [ "$IN_FILE_ID" = "null" ]; then
  echo "Upload failed"; exit 1
fi
After watermark
if [ -z "$OUT_FILE_ID" ] || [ "$OUT_FILE_ID" = "null" ]; then
  echo "Watermark failed"; exit 1
fi

Known Limitations

RGBA PNG (4-channel): The upstream image processing service may return a 500 error for images with alpha channel. Workaround: convert to JPEG before uploading (sips -s format jpeg input.png --out input.jpg on macOS).