Gotenberg
Send a document, receive a PDF: Gotenberg is a Docker-based, stateless HTTP conversion API trusted in production by thousands of companies and adopted by notable open-source projects. Send files as multipart/form-data, get a PDF back; Chromium, LibreOffice, and fonts are the container's problem, not yours. Headless Chromium handles URLs, HTML templates, and Markdown with pixel-perfect browser rendering: it executes JavaScript, loads web fonts, waits for network idle, a JS expression, or a DOM selector before rendering SPAs, and accepts injected cookies and HTTP headers for authenticated pages. LibreOffice converts 100+ office formats - .docx, .xlsx, .pptx, and legacy formats - with page-range extraction and PDF/A archival conformance. Built-in PDF engines round out the pipeline in every image variant: merge, split, rotate, flatten, encrypt, watermark, stamp, read/write metadata and bookmarks, plus Factur-X/ZUGFeRD e-invoicing and PDF/UA accessibility compliance. Screenshots of URLs and HTML come from the same endpoints. Zero-transfer pipelines stream files directly between S3, MinIO, or GCS presigned URLs and Gotenberg, bypassing your application entirely, and webhooks enable async processing. Statelessness means horizontal scaling is trivial - run as many replicas as your conversion volume demands. Three image variants (full, Chromium-only, LibreOffice-only) trim the footprint to what you actually use.
phpMyAdmin
Since 1998, phpMyAdmin has been the standard web interface for MySQL and MariaDB - the tool millions of developers, DBAs, and hosting companies reach for when a database needs inspecting, fixing, or migrating. Written in PHP, it covers effectively the entire administration surface: create, browse, alter, and drop databases, tables, views, columns, and indexes; insert and edit rows through a tabular editor; manage user accounts and granular privileges; and maintain stored procedures, triggers, and events - all without touching a command line. The SQL editor executes arbitrary queries with syntax highlighting, autocompletion, history, and bookmarkable statements, including batch queries. Import/export is a migration workhorse: read SQL, CSV, XML, and OpenDocument spreadsheets in; write out to SQL dumps, CSV, JSON, XML, PDF, Word, LaTeX, and more - the fastest path for moving a WordPress database or handing a schema to a colleague. The Designer view renders your schema as an interactive ER diagram with drag-and-drop relationship editing, and data transformations display BLOBs as images or download links inline. Server maintenance views surface configuration suggestions. Multi-server support, dark mode, and translations into 72 languages round out a tool that earns its ubiquity. GPL-licensed.
Hastebin
"Throw it on a haste and send the link" entered developer vocabulary because of Hastebin (haste-server), the minimalist open-source pastebin. Written in Node.js with three stated design goals - be really pretty, be really simple, be easy to set up - it does one job precisely: paste code, logs, stack traces, or config snippets, press save (or Ctrl+N for a new one), and get a short random-key URL to share. Syntax highlighting renders pastes readably across common languages, a raw view serves plain text for curl and scripts, and duplicate-and-edit makes iterating on a shared snippet trivial. The killer workflow is the terminal: with the haste-client utility or a one-line shell function, `cat error.log | haste` prints a shareable URL straight from stdout - the fastest route from a broken build to a colleague's eyeballs. Storage is pluggable through a simple adapter interface: filesystem by default, Redis with optional key expiration for pastes that should age out, and configurable key length, maximum paste size, and static documents. Self-hosting matters here because pastes often contain internal logs and stack traces that should never sit on a public pastebin - your instance keeps them inside your network, under your retention rules.
Aptabase
Web analytics tools ignore native mobile, desktop, and game apps; Aptabase was built for exactly those. If Firebase Analytics would force a privacy-policy footnote you don't want to write, this is the alternative - session-based metrics with no cookies, no IDFA or GAID, no device fingerprinting, and a daily-rotated salt that makes cross-day re-identification mathematically impossible. That design means GDPR, CCPA, and PECR compliance out of the box and "Data Not Collected" App Store privacy labels without ATT prompts. The SDK coverage is the widest in its category: eleven first-party libraries spanning Swift, Kotlin, Flutter, React Native, Tauri, Electron, .NET MAUI, NativeScript, Unity, Unreal Engine, and JavaScript for web - each MIT-licensed, following platform conventions, and accepting a custom host parameter that points at your instance. Integration is minutes: initialize with an app key, call trackEvent with optional properties, and the dashboard shows sessions, events, app versions, OS breakdowns, and country-level geography. The self-hosted stack is a .NET server over PostgreSQL for metadata and ClickHouse for high-volume event ingestion, giving cloud-parity features under an AGPL license. For indie iOS/Android apps, Electron and Tauri tools, and Unity or Unreal games, it replaces Firebase without the Google entanglement.
Hasura
A PostgreSQL database becomes a production-grade GraphQL API the moment Hasura GraphQL Engine points at it: track tables and relationships - existing schemas included - and full query, mutation, and subscription types appear with where, order_by, limit, offset, and on_conflict arguments, no resolvers or boilerplate written. Its Haskell core compiles GraphQL to efficient SQL, and any query becomes a real-time live query with a single keyword, powering dashboards and collaborative UIs over standard GraphQL subscriptions. Authorization is where Hasura earns its enterprise reputation: role-based access control with row- and column-level permission policies driven by session variables from JWTs, auth webhooks, or headers - each role effectively sees its own GraphQL schema containing only what it may touch, integrating cleanly with Auth0, Firebase, or homegrown auth. Event triggers fire webhooks on inserts, updates, and deletes for asynchronous business logic; Actions extend the schema with custom REST handlers; remote schema stitching merges external GraphQL services into one endpoint; and auto-generated REST endpoints serve clients that skip GraphQL. A browser console handles data modeling and API exploration, the CLI manages migrations and metadata as code, and deployment is a single stateless Docker container beside Postgres.
Countly
Mixpanel, OneSignal, and Crashlytics in one self-hosted stack - Countly is an all-in-one product analytics and engagement platform where every byte of first-party data stays on your server. A Node.js application over MongoDB, it collects through ten battle-tested SDKs spanning iOS, Android, web JavaScript, React Native, Flutter, Unity, and desktop (plus a data write API for anything else), and has powered tens of thousands of mobile, web, and desktop apps since 2012. The analytics core covers sessions, custom events, views, user profiles, and real-time dashboards, with exploration tools built for product managers as much as analysts. What separates Countly from pure analytics tools is acting on the data without third parties: built-in push notifications send automated, transactional, and personalized messages to iOS (APNs), Android (Firebase), and Huawei devices, with the SDK handling token retrieval and permission flows automatically; crash reporting captures symbolicated native crashes on iOS and Android plus JavaScript errors, correlated with the same user and session data. Email reports keep stakeholders updated, and the plugin-based architecture means features load as modules. For GDPR-sensitive products, engagement without piping user data to advertising companies is the entire point. AGPL-licensed server, installable in minutes.
ByteStash
The functions, config files, and one-liners you keep re-deriving finally get a searchable home: ByteStash is a self-hosted code snippet manager - a private Gist. Each snippet holds multiple code fragments, so a Docker Compose file, its .env template, and a plaintext usage note live together under one titled, categorized entry. Monaco-based syntax highlighting covers dozens of languages, from Python, TypeScript, Go, and Rust to YAML, Dockerfiles, Terraform, and Markdown. Retrieval is the point: filter by language or category, search titles and descriptions, and optionally include snippet contents in full-text search. Snippets can be pinned for quick access and shared via public links that recipients open without an account. Multi-user support runs on JWT authentication with optional OIDC single sign-on for teams on centralized identity, and a full CRUD REST API with Swagger documentation wires snippet retrieval into editors, scripts, and CI pipelines. Storage is a single SQLite database with optional encryption, and collections export as JSON or Markdown. A React frontend on a Node.js backend, deployed as one lightweight container.
Ackee
Page views, referrers, browsers, and screen sizes - Ackee delivers the analytics developers actually check, from a deliberately minimal Node.js and MongoDB stack that skips both Matomo's weight and Google Analytics' cloud dependency. Its defining constraint is anonymization: no cookies, no unique user tracking, and a multi-step anonymization process that keeps visitors unidentifiable while the aggregate numbers stay useful. In its default anonymous mode Ackee collects no personally identifiable information at all, which means GDPR and CCPA compliance out of the box and no cookie consent banner on your sites. A detailed mode adds screen size, language, and per-visit referrers - still without cookies or fingerprinting. Integration mirrors the Google Analytics pattern: create a domain in settings, drop the generated ackee-tracker snippet into your pages, and data appears in a clean single-page dashboard. One instance tracks multiple domains, and custom events capture button clicks, signups, and conversions. The distinctive engineering choice is the fully documented GraphQL API: everything the dashboard shows comes from that API, so you can query active visitors, average duration, and view statistics programmatically, feed data in from apps and services beyond websites, or build an entirely custom interface on top. If you want bare-minimum analytics with a real API and zero privacy anxiety, this is the tool.
Carbone
Document-generation code is the worst kind of code in your backlog - Carbone kills it. Its insight is separating design from data - templates are ordinary office documents (DOCX, ODT, XLSX, PPTX, HTML, even custom XML) built in LibreOffice, Microsoft Office, or Google Docs, with mustache-like markers such as {d.companyName} typed directly into the text. Send a template plus JSON from your existing APIs to the HTTP API, and Carbone returns the finished document - exported as-is or converted to PDF, XLSX, CSV, HTML, PNG, EPUB, and more via its integrated LibreOffice converter (Chromium and OnlyOffice engines are also supported for HTML-fidelity and office-format conversions). The template language goes well beyond substitution: loops over arrays render dynamic table rows, filters and aggregations run inside the document, and built-in formatters handle dates, numbers, currencies, timezones, and locales, with custom JavaScript formatters when needed. One template serves multiple languages through translation markers with auto-maintained translation files. The XML-agnostic engine means anything your document editor can design - pagination, headers, footers, nested tables, charts - survives generation intact, and Carbone guarantees no breaking changes in template syntax. Node.js-based, fast via multi-threaded LibreOffice conversion. The invoices, contracts, and reports your product owes its users become template edits, not sprints.
Redmine
Nearly two decades running engineering organizations: Redmine is the veteran open-source project management and issue tracker, a Ruby on Rails application (GPLv2) still in active development. Its core strength is configurability: define your own trackers (bug, feature, task, or anything else), issue statuses, and role-based workflows that control exactly which transitions each role may perform, then extend records with custom fields of every type. Issues support subtasks, relations (blocks, precedes, duplicates), watchers, categories, and full journaled history, with saved custom queries and cross-project filtering for slicing the backlog any way you need. Around the tracker sit Gantt charts and calendars, a roadmap driven by versions, per-project wikis, forums, news, and document repositories, plus time tracking with estimated versus spent hours and activity-based reporting. Multi-project support runs deep - subprojects, per-project modules, and granular role-based permissions - and repository integration (Git, Subversion, Mercurial) links commits to issues automatically. Email notifications, inbound email-to-issue creation, LDAP authentication, a REST API, and a large plugin and theme ecosystem round it out. Recent 6.x releases brought substantial query and rendering optimizations. Self-hosting keeps your entire project history in your own database, free of per-seat licensing.
mCaptcha
The CAPTCHA bargain - annoy your users and feed their behavior to Google - gets replaced with economics by mCaptcha. Instead of image puzzles, it uses SHA256 proof-of-work: every visitor's browser silently solves a small computational challenge (via a WebAssembly library) before submitting a form. Humans never notice the milliseconds; bots hammering your site must burn more compute sending requests than your server spends answering them, which makes attacks more expensive than defense - the property that also makes mCaptcha genuine DoS protection, not just bot filtering. Written in Rust, the system is fully automated: difficulty scales with traffic, so challenges stay trivial in normal conditions and harden under attack. The privacy and accessibility wins are structural rather than promised: no tracking, no profiling, no user-pattern data collection, and no visual puzzles that exclude users with visual or cognitive impairments - the design was published in Communications of the ACM. Rate limiting is IP-independent, so users behind NATs, VPNs, or Tor get the same experience instead of endless challenge loops, and proofs resist replay attacks, neutering captcha farms. Migration is deliberately easy: the API is compatible with reCAPTCHA and hCaptcha, making it a drop-in replacement. AGPL-licensed core with proprietary-friendly client libraries.
Cockpit
Built by an agency in 2011 and refined by real client work since, Cockpit is a headless CMS whose pragmatism is earned. It's a pure content backend: model your data, let editors manage it, and fetch it over REST or GraphQL from any frontend - React, Vue, Flutter, a static site generator, or an IoT dashboard. Content modeling covers three shapes: Collections for repeatable items (posts, products, events), Singletons for one-off content (settings, about pages), and Trees for hierarchies (navigation, categories), all assembled from 20+ field types including relationships. The API layer is unusually capable: MongoDB-style query filtering, field selection to trim payloads, automatic image optimization through the assets API, and built-in caching. Localization is first-class with per-field multi-language content and fallback support; user management includes roles, granular permissions, two-factor authentication, and API tokens; and webhooks push changes into external workflows. Agencies get multi-tenant Spaces - several sites or clients from one installation. The operational footprint is refreshingly small: PHP plus either SQLite or MongoDB, no build steps, no toolchain, extensible through hooks, events, and addons (pages/SEO, forms, full-text search, layout components). Where enterprise headless platforms bill per seat and per locale, Cockpit is MIT-licensed and simply yours.
Motor Admin
Stop building internal tools and ship your actual product - Motor Admin exists for exactly that. Point this Ruby/Vue application at a PostgreSQL, MySQL, MariaDB, or SQL Server database and it generates a complete CRUD admin panel from your schema in under a minute - search, filters, create, update, delete, all through a polished UI, with every customization done through in-app settings rather than a DSL or boilerplate code. What elevates it beyond CRUD generators is the business-intelligence half: write SQL queries (with variables) and render results as tables, numbers, line/bar/ pie charts, funnels, or markdown; organize reports into shared dashboards; and attach queries and dashboards directly to resource pages as tabs, so an order record shows its revenue history in place. Operations beyond CRUD are covered by custom actions and a WYSIWYG forms builder that posts to your existing REST or GraphQL APIs - send a refund, trigger an email, whatever your backend exposes. Email alerts deliver scheduled reports, Slack sends personalized report alerts, and intelligence search spans all resources. Governance is included: role-based permissions with row- and column-level control (CanCanCan), an audit log of admin activity, multiple database connections, and configuration sync between staging and production. Mobile-optimized, AGPL-licensed, also available as a Rails engine.
CodeX Docs
Writing docs should feel like editing a modern document, not wrangling Markdown files - CodeX Docs delivers that on Editor.js, the block-styled editor its CodeX team builds and thousands of products use. Content is composed from clean blocks (headings, lists, code, images, embeds) with a UI that reads well on both desktop and mobile, and pages render statically with human-readable, SEO-friendly URLs. Structure is free-form: pages nest to any depth, so a flat FAQ and a deep product manual coexist in one instance, and the UI tunes to fit - collapse sections, hide the sidebar. The operational footprint is deliberately tiny. No database is required: the default driver persists to a local folder, with MongoDB available when you want it, and the whole app configures through one YAML file (overridable with APP_CONFIG_ environment variables) covering title, start page, auth password, and JWT secret. Editing mode sits behind password authentication. Thoughtful extras are wired in: readers can report misprints straight to your Telegram or Slack, Hawk error tracking catches frontend and backend exceptions, and Yandex Metrica analytics is a one-line config. A ready-made Helm chart covers Kubernetes. Written in TypeScript.
Hasty Paste
Paste some text, hit save, share the link - Hasty Paste is a fast, minimal pastebin written in Python on the async Quart framework, named, by its author's own admission, "because you use it so fast without a care in the world." No accounts, no authentication, no friction - built for the everyday case of handing a debug log, config snippet, or stack trace to someone in tech support or a chat channel. Pastes get randomly generated IDs, with an optional "long" ID mode that makes brute-force URL guessing impractical, and expiry times ensure throwaway content actually gets thrown away. Optional Pygments syntax highlighting makes code readable, a dark theme spares your eyes, and the whole interface works without JavaScript - it renders in terminal browsers and under the strictest script blockers. Storage is a custom flat-file system (no database), caching runs internally or through Redis for busier instances, and a REST API plus the companion "Hastily Paste It" CLI script enable piping command output straight into a paste from the terminal. The Alpine-based Docker image is tiny, resource usage is minimal, and the license is AGPL.
Oxigen
The social preview cards shown when links hit Twitter, LinkedIn, Slack, or Discord, generated on the fly: Oxigen is a small Go service for dynamic Open Graph images, no designer required per page. Instead of exporting static images per page, you compose a card once and drive it with parameters: title, author, website, logo, background image, and background dimming all arrive as URL query arguments, so your og:image meta tag simply points at the Oxigen endpoint with the page's own values substituted in. Every blog post, product page, and doc gets a branded, correctly sized preview generated on the fly. A built-in web UI covers interactive composition - tweak the text and imagery, watch the preview update, copy the resulting URL - while the same rendering path serves programmatic API use from static site generators, CMS templates, or build pipelines. Rendering is pure Go using the gg 2D graphics library, freetype fonts, and the imaging package, built on the kyoto framework by that project's author. Deployment is one stateless container on port 80 with no database and no external dependencies, so instances scale and restart freely.
GlitchTip
GlitchTip speaks Sentry's protocol without Sentry's operational weight - open-source error tracking that your existing SDKs already understand. The pitch is pragmatic: instrument your application with the official Sentry SDKs you already know - any language they cover - and point the DSN at your own GlitchTip instance instead. Errors, exceptions, log messages, and Content Security Policy violations flow into one place for triage, grouped into issues with stack traces, with alerts delivered by email or webhook the moment things break. Where self-hosted Sentry has ballooned into a docker-compose stack of twenty-plus containers, GlitchTip is a deliberately lean Django and PostgreSQL application a small team can actually run. Beyond errors, it bundles three more monitoring concerns: performance monitoring takes a works-out-of-the-box approach - no dashboard building, just your slowest web requests, database queries, and transactions surfaced automatically; uptime monitoring pings your sites and alerts on failures, or runs in reverse as a dead-man's-switch heartbeat for cron jobs that must check in on schedule; and log search puts application logs alongside errors for faster debugging. Unlimited projects and team members, MIT-licensed, built by Burke Software - your event volume is limited only by your own hardware.