johanneskaufmann/html-to-markdown

html-to-markdown is a Go library and command-line tool that converts HTML content into Markdown text. Markdown is a lightweight text format used by many writing tools, documentation systems, and AI applications. The library handles the conversion of common HTML elements: bold and italic text, ordered and unordered lists with nesting, blockquotes, inline code and code blocks, links, images, and HTML tables with alignment, rowspan, and colspan support. The library is designed to handle edge cases that simpler converters miss. It escapes special characters only when necessary to avoid accidentally triggering Markdown formatting, and it correctly handles multi-line links and nested blockquotes. You can also tell it to keep certain HTML tags as-is in the output, or to strip them out entirely, which is useful when you want to preserve some structure that Markdown cannot express. The architecture is plugin-based. A base plugin provides shared functionality, and a Commonmark plugin handles standard Markdown output. Additional plugins cover things like strikethrough text and table conversion. You can write your own plugins to handle custom HTML elements or web components. The converter also lets you register how specific tag types (block-level versus inline) should be treated, which affects how whitespace is handled around them. For Go developers, the library is imported as a module and conversion can be as simple as one function call: pass in an HTML string and get back a Markdown string. For converting whole pages, a WithDomain option turns relative URLs into absolute ones. A CLI version lets non-Go users run conversions from the terminal without writing any code. An online demo and a hosted REST API are available for quick testing without installation. The project is on version 2, which has breaking changes compared to version 1. Both versions are available on separate branches.