Sites like payum.dev

OpenFaaS, a serverless functions platform for deploying event-driven functions on Kubernetes or at the edge, run by OpenFaaS Ltd

DDEV, an open-source local development environment tool for web developers, documented on its project website with about and brand pages

The Doctrine Project's home page for PHP libraries on database storage, object mapping, and an ORM and DBAL, with contributor guide

Ecotone, a PHP architecture framework for event sourcing, sagas, workflows, outbox and distributed messaging by its team

PHPUnit project website by Sebastian Bergmann covering the PHP testing framework, its releases, documentation, sponsors and community events

Prettier, an opinionated code formatter for JavaScript, CSS, Markdown and other languages, with editor and CI integrations

Nuno Maduro's personal site on his PHP and Laravel open-source work, talks, sponsorships and blog posts

Yarn, a JavaScript package manager; its documentation and API reference for the @yarnpkg packages

Vite, a frontend build tool and development server for modern web projects, documented by its core team

YajraBox is a documentation site for open source Laravel packages such as DataTables, Oci8 and ACL, by developer Yajra

Packagist, the main public repository of PHP packages installable with the Composer dependency manager, with package search, API and feeds

Mockoon, a free open-source desktop app and CLI for designing and running mock APIs locally, plus the Mockoon Pro team service

Half Half Travel is a travel blog by Becca and Dan covering destination guides, remote work tips, and gear reviews

MapStruct is a Java code generator project for simplifying bean-to-bean mappings, documented on its official project website

Floating UI, a JavaScript library and documentation site for positioning tooltips, popovers and dropdowns next to reference elements

UserFrosting is an open source PHP framework for building user management systems, with sign-in, roles and permissions

Consuming Knowledge, a personal blog by software developer Brian Nesbitt on programming, code reading, and family

Support Ukraine Now is a Ukrainian NGO running advocacy, leadership and volunteer programmes linking international partners with Ukrainian civil society

Ramda, a documentation site for a practical JavaScript functional programming library and its function reference

NumFOCUS, a nonprofit charity supporting open source scientific software projects such as SciPy, pandas and Jupyter

AsyncAPI, an open source initiative and specification with tools for defining and documenting event-driven architectures, under the Linux Foundation

Personal site of developer Hsiaoming Yang blending open source tool notes, bilingual English and Chinese essays, and travel photographs

Typelevel is an open-source community developing Scala libraries for functional programming, with events and meetups

Sindre Sorhus's website presents his Mac, iOS and open-source apps, such as the Aiko transcription tool and Dato menu bar calendar

Biome, an open-source toolchain for web projects that formats, lints, and checks JavaScript, TypeScript, and related code

A PHP static analysis tool called PHPStan, free and open-source, that finds bugs in code without tests, by Ondřej Mirtes

PostCSS, a JavaScript tool documentation site for transforming CSS with plugins such as Autoprefixer and its API reference

Badgen, a service generating status badges for software projects, such as package versions, ratings and downloads, from URLs

phpDocumentor, a documentation tool that generates API reference docs from PHP source code, with its supporting components

Nominatim, an open-source geocoding software and API using OpenStreetMap data for place name and address lookup, maintained by Sarah Hoffmann

Star History, a web tool charting and comparing GitHub repository star growth over time, with rankings and category comparisons

The Rollup JavaScript module bundler's official website, with documentation, FAQs, an online REPL and browser build guides

Rocket.Chat, an open source team chat and collaboration platform for secure, self-hosted government and enterprise communications

A JavaScript UI library site for Preact, a small React-like framework, with its blog, docs and branding pages

Mocha, a JavaScript test framework for Node.js and browsers, with its project documentation and API reference

Tiptap, a headless open-source rich text editor framework and its commercial cloud platform for building custom editors

Filament, a PHP admin panel framework's documentation, themes and tutorials site for building Laravel application interfaces

Spatie, a Belgian web development studio building Laravel and AI applications, courses and open-source PHP packages, with a blog and docs

Blog by web standards leader Lea Verou on CSS, web design, icons and open source developer tools

A documentation site for pre-commit, a framework for managing and running git pre-commit hook scripts before code review

Typst, a markup-based typesetting system and online document creation tool for writing, automating and formatting reports and papers

DevDojo is an AI website builder for developers, with a browser visual editor, templates, and Laravel auth and app features

Zulip, an open-source team chat application with threaded async messaging, API documentation and help center, by Zulip developers