Developer Utilities

Free browser-based tools built for everyday development tasks

Each tool on this page was built to solve a problem I kept running into during projects. They run entirely in the browser where possible, require no sign-up and collect no data. If a tool needs server processing (such as AVIF encoding) files are handled in memory and discarded immediately.

Image Optimizer

Convert images to AVIF, WebP, JPEG and PNG. Compare sizes across formats and quality levels, then download individually or as a ZIP with picture element HTML.

eBay Sales Viewer

Retrieve the full sales history for any eBay listing using the legacy endpoint that was removed from public view in 2023.

String & Code Converter

Paste markup or text and convert to C# strings, JavaScript, JSON, Base64 or URL-encoded output. Includes JSON prettify and minify.

Colour Scheme Designer

Pick a base colour from the wheel and generate palettes using complementary, triadic, analogous and other harmony modes. Export as CSS variables.

About These Tools

The image optimizer uses SixLabors ImageSharp for JPEG, WebP and PNG encoding and libvips for AVIF via the AV1 codec. The URL scanner fetches page HTML, extracts every <img>, <source srcset> and CSS background-image reference, then processes each image individually so you can see exactly where savings are available.

The string converter handles the quoting and escaping rules that differ between C#, JavaScript and JSON. It is particularly useful when embedding HTML templates inside C# code or preparing payloads for API calls. All conversions happen client-side in JavaScript.

The colour scheme designer implements standard colour theory harmonies (mono, complementary, split-complementary, triadic, tetradic and analogous) calculated from a single base hue. The generated CSS variables can be copied directly into a stylesheet.