CamScanner Add Watermark

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.

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

bash

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:

json

{
  "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):

bash

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):

bash

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:

json

{
  "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

bash

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

bash

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

bash

# 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).