Replace & Invert Color

Replace pixels matching a source color with a target color, or make them transparent. Uses Euclidean distance in RGB space with configurable tolerance for smooth blending at color boundaries.

API Endpoint

POST /api/v1/tools/replace-color

Accepts multipart form data with an image file and a JSON settings field.

Parameters

Parameter	Type	Required	Default	Description
sourceColor	string	No	"#FF0000"	Hex color to find (format: #RRGGBB)
targetColor	string	No	"#00FF00"	Hex color to replace with (format: #RRGGBB)
makeTransparent	boolean	No	false	Make matching pixels transparent instead of replacing with target color
tolerance	number	No	30	Color matching tolerance (0 to 255). Higher values match a wider range of similar colors

Example Request

curl -X POST http://localhost:1349/api/v1/tools/replace-color \
  -H "Authorization: Bearer si_your-api-key" \
  -F "[email protected]" \
  -F 'settings={"sourceColor": "#FF0000", "targetColor": "#0000FF", "tolerance": 40}'

Make a green background transparent:

curl -X POST http://localhost:1349/api/v1/tools/replace-color \
  -H "Authorization: Bearer si_your-api-key" \
  -F "[email protected]" \
  -F 'settings={"sourceColor": "#00FF00", "makeTransparent": true, "tolerance": 50}'

Example Response

{
  "jobId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "downloadUrl": "/api/v1/download/a1b2c3d4-e5f6-7890-abcd-ef1234567890/photo.png",
  "originalSize": 2450000,
  "processedSize": 2100000
}

Notes

• Color matching uses Euclidean distance in RGB space, scaled by tolerance * sqrt(3).
• Replacement blending is proportional to color distance: pixels closer to the source color receive more of the target color, creating smooth transitions.
• When makeTransparent is true, the output is forced to PNG (or WebP/AVIF) if the input format does not support alpha channels (e.g., JPEG).
• A tolerance of 0 matches only the exact source color. Higher values (50+) will match a broader range of similar hues.
• Output format matches the input format unless transparency is needed and the input format lacks alpha support.