Tiny Code Editor with Plugins and Syntax Highlighting – Yace
Build embedded code, Markdown, prompt, or token editors with Yace and load only the highlighters and editing behavior each field needs.
JavaScript & CSS code editor
Feature-rich Code Editor With Autocomplete – Petrel.js
An easy-to-use library called Petrel which allows developers to create feature-rich code editors in a couple of minutes
Online HTML Editor With Instant Preview
A basic HTML editor with instant preview app that allows you to edit HTML code directly on a live website or instantly see how HTML code will render.
Minimal Clean Code Editor – iblize
A minimal clean Code Editor that supports over 250 languages.
Mobile-friendly Online Code Editor/Playground – WebDen
An open-source online code editor/playground that allows you to edit and run HTML/JS/CSS codes on the client side.
Simple Extensible Code Editor – Copenhagen
A simple, lightweight, extensible code editor that supports popular languages like HTML, CSS, JavaScript, JSON, Markdown, and Plain Text.
Cross-browser Code Editor For Browser – codejar
codejar is a small JavaScript library to insert a cross-browser text/code/markup editor on the webpage.
Tiny HTML/CSS/JavaScript Code Editor – OnCode
A small, fast, pretty clean HTML/CSS/JavaScript code editor with support for autocomplete/autosuggest and syntax highlighting.