Hotpatch by orindholt

Hotpatch is a sidebar code editor for tweaking the sites you use. Write a CSS or JS patch and it applies to every page of that site, on every visit. CSS updates live as you type; JS runs on page load. Patches are scoped per site and stored on your device.

Open the sidebar on any http(s) page and you get a tabbed editor for that site's patches, no devtools, no scratch files, nothing to re-paste after a reload.

WHAT YOU CAN DO

• Write CSS patches that are injected into every page of the site and update instantly while you type, hide clutter, fix contrast, widen a cramped layout, restyle anything.
• Write JS patches that run automatically on page load, or hit "Run now" to execute one against the current tab immediately.
• Keep as many patches per site as you like, each with its own tab, name, and enable/disable switch.
• Highlight matches: with a CSS patch open, turn on Highlight and Hotpatch outlines every element matched by the rule your cursor is sitting in, so you can see what a selector actually hits.
• Manage everything from one place, the overview lists all patches grouped by site, with toggles and delete buttons, so you can find and disable something without visiting the site first.

THE EDITOR

Built on CodeMirror 6 with syntax highlighting, autocompletion, bracket matching and closing, code folding, line numbers, and undo history. Prettier formatting on demand (Cmd/Ctrl-Shift-F) or automatically on save (Cmd/Ctrl-S). Live linting flags syntax errors before a patch ever reaches the page. 14 editor themes across light and dark — GitHub, Dracula, Nord, Solarized, Tokyo Night, Catppuccin, Gruvbox, Monokai, One Dark, and more — plus configurable font size, tabs or spaces, indent width, and line wrapping. You can also set default starting code for new CSS and JS patches.

Edits save themselves as you type. There is no save button to forget.

PRIVACY

Hotpatch collects nothing and sends nothing anywhere. Your patches and settings live in your browser's local extension storage — no account, no sync server, no analytics, no network requests of any kind.

NOTES

Patches only work on http(s) pages; browser-internal pages, extension pages, and local files can't be patched. Broad site access is required because a patch can target any site you choose to write one for.