Compress Image

Reduce image file size by specifying a quality level or a target file size in kilobytes. The tool uses iterative binary search to hit size targets accurately.

Target sizes count 1 KB as 1000 bytes, the way upload forms do, so a 20 KB target never returns more than 20,000 bytes. The tool lowers quality first. If that isn't enough, it scales the image down step by step, and the response then includes resizedTo with the final width and height. If even the smallest step can't reach the target, the request fails with a message saying so.

API Endpoint

POST /api/v1/tools/image/compress

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

Parameters

Parameter	Type	Required	Default	Description
mode	string	No	"quality"	Compression mode: quality or targetSize
quality	number	No	80	Quality level (1-100). Used when mode is quality.
targetSizeKb	number	No	-	Target file size in KB (1 KB = 1000 bytes). Used when mode is targetSize.

Example Request

Compress to quality 60:

curl -X POST http://localhost:1349/api/v1/tools/image/compress \
  -H "Authorization: Bearer si_your-api-key" \
  -F "file=@photo.jpg" \
  -F 'settings={"mode": "quality", "quality": 60}'

Compress to target size of 200 KB:

curl -X POST http://localhost:1349/api/v1/tools/image/compress \
  -H "Authorization: Bearer si_your-api-key" \
  -F "file=@photo.jpg" \
  -F 'settings={"mode": "targetSize", "targetSizeKb": 200}'

Example Response

{
  "jobId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "downloadUrl": "/api/v1/download/a1b2c3d4-e5f6-7890-abcd-ef1234567890/photo.jpg",
  "originalSize": 2450000,
  "processedSize": 204800
}

Notes

• In quality mode, lower values produce smaller files with more compression artifacts. A value of 80 is a good default for web use.
• In targetSize mode, the engine performs iterative compression to get as close to the target as possible without exceeding it.
• Output format matches the input format. The compression applies to the format's native encoding (e.g. JPEG quality for JPEG files, WebP quality for WebP files).
• If the default quality (80) is acceptable, you can omit the quality parameter entirely.