Converter tools

About these converter tools

This page collects the conversions that come up over and over when moving data between systems — spreadsheets to APIs, configuration formats to each other, encoded blobs back to text, and timestamps between formats a human can read and ones a database expects. They are the kind of tasks where a fast browser tool beats writing a one-off script.

What is on this page

The tools group around three jobs. Data format converters translate structured data between representations — the CSV to JSON converter reads a spreadsheet export and produces a JSON array suitable for an API or a fixture file, and the YAML to JSON converter moves between the formats most configuration systems alternate between (Kubernetes, GitHub Actions, OpenAPI). Markup converters move between document formats — the HTML to Markdown converter cleans up a copy from a web page or rich text editor and produces Markdown you can paste into a README, a blog post, or a documentation site. Encoding and time converters handle the lower-level transforms — Base64 encoding, URL encoding, and the Unix timestamp converter, which translates between epoch seconds and human-readable dates in your local timezone or UTC.

Which to use when

Use the CSV to JSON converter when migrating data into an application that does not accept spreadsheets directly, or when seeding test fixtures from a finance or marketing export. Use the YAML to JSON converter when debugging a tool that requires one format but you authored configuration in the other — it is also useful for validating that your YAML actually parses. Use the HTML to Markdown converter when capturing content from the web into a writing workflow that uses Markdown. Use the unit converter for the cross-cutting cases — length, weight, temperature, data size — where a quick answer beats opening a calculator.

Privacy

Every converter on this page runs in your browser. Inputs are parsed, transformed, and rendered on your device — they are never uploaded to a server, logged, or stored remotely. That makes the tools safe for proprietary data exports, internal configs, and anything else you would not paste into a third-party service.