"Make ~/Downloads/signature.jpg fit the IBPS signature rules"

Saved ~/Downloads/signature.fit.jpg for IBPS signature (JPEG, 140 × 60 pixels, 10 KB to 20 KB): 10,240 bytes (10.0 KB), under the 20,000 bytes limit.

Any limit: "get this scan under 300 KB", "this photo under 50 KB".
Form presets: US visa photo (DS-160), Indian e-Visa passport page and photo, IBPS, SBI and RRB uploads. The preset sets the size limit, the minimum size and the exact pixels. Ask for list_forms to see them all.
Keeps as much quality as the limit allows, and saves the result next to the original as <name>.fit.<ext>.
Free, no account, no API key.

Setup

Needs Node.js 20.10 or newer.

Claude Code

claude mcp add fitfilesize -- npx -y fitfilesize-mcp

Claude Desktop, Cursor, Windsurf and other clients that use an mcpServers config file:

{
  "mcpServers": {
    "fitfilesize": {
      "command": "npx",
      "args": ["-y", "fitfilesize-mcp"]
    }
  }
}

(Claude Desktop: Settings → Developer → Edit Config. Cursor: ~/.cursor/mcp.json.)

VS Code (.vscode/mcp.json):

{
  "servers": {
    "fitfilesize": { "command": "npx", "args": ["-y", "fitfilesize-mcp"] }
  }
}

Tools

`fit_file`

Argument
`path`	Full path to the file (`~/` works). PDF, JPEG, PNG, WebP, TIFF or BMP.
`limit`	The upload limit, like `"200KB"` or `"1.5MB"`. KB and MB are 1000-based, so the result passes a check done either way.
`form`	Instead of `limit`: a form preset from `list_forms`, like `"ibps-photo"`.
`width`, `height`	Optional exact pixel size, images only.
`fit`	`"crop"` (default) or `"pad"` with white, when the pixel size changes the shape.
`minimum`	Optional smallest size, like `"10KB"`. A small JPEG is padded up to it; the picture is unchanged.
`output`	Optional path for the result.

`list_forms`

The form presets, each with its rules and the official source they come from. The list is read from fitfilesize.com/forms.json, so new forms appear without an update; a copy is bundled for when the site cannot be reached.

Privacy

The file is sent to FitFileSize's server over HTTPS, compressed there, and deleted as soon as the result is saved on your computer. Nothing else leaves your machine. See the privacy page. Uploads count against the site's free limit of 30 an hour.

Development

npm install
npm test          # the tools through an MCP client, against a stand-in API
npm run build     # bundles the form presets from the website's data

FITFILESIZE_API points the server at another API, such as a local one (http://127.0.0.1:8000).