Summer is here — and so is the best excuse to stock up on the tools, skills, and free software that actually move the needle for builders and small businesses.

At ANDRS Tech Foundry, we believe great software shouldn't come with a great price tag. So we're kicking off Open Source Summer: a living collection of the best open source tools across every layer of the builder stack.

Whether you're a solo founder, a small team, or just someone who loves creating and building things — this list is for you.

What we're collecting

We're going broad and practical. Expect picks across:

Why open source?

Open source tools give you something SaaS rarely does: ownership. No vendor lock-in, no sudden pricing changes, no features hidden behind a paywall. You can self-host, fork, and adapt.

For small businesses especially, this matters. The right open source stack can save thousands a year — and give you more control over your own data in the process.

2026 highlights so far

A few stories worth calling out from this year already:

This is a living list. We'll keep adding to this collection throughout the summer. Have a tool you swear by? Drop it in the comments — we'd love to feature community picks too.

Stay tuned. Summer's just getting started. ☀️

— The ANDRS Tech Foundry team

Dev tools — editors, CLIs, local-first apps, and productivity boosters

  1. Zed — a fully open source, Rust-built code editor from the original Atom creators. Sub-second startup, native AI chat and completion with your choice of provider, and it stays fast even with a big project open.
  2. Bruno — an open source, offline-first API client for REST, GraphQL, gRPC, and WebSockets. Collections live as plain text .bru files in your repo, so they version and review like code — no account, no cloud sync required.
  3. AppFlowy — an open source, local-first alternative to Notion for docs, databases, and project boards. Built in Rust and Flutter, works offline by default, and is self-hostable if you want sync without the SaaS bill.
  4. fzf — a general-purpose command-line fuzzy finder. Pipe any list into it — files, git branches, shell history, running processes — and filter it interactively in your terminal. A small tool that quietly saves a lot of time.

Design & UI — open source Figma alternatives, component libraries, icon packs

  1. Brand Assets Generator by Jordan Stoyanov, who helps growing companies turn strategy into high-performing brands, websites, and digital products. The generator includes various preset images to use, but you can also upload your own — we used it to create the header art on this very post.
  2. Gradientool — a gradient creator tool by Leo Benzoni, an absolutely beautiful free tool with endless possibilities to create gradients as MP4s or PNGs.
  3. gifski — makes smooth GIF animations using advanced techniques that work around the GIF format's limitations. You can also use it in your own free applications.
  4. React Bits — highly customizable animated components and backgrounds you can simply drop into your project. Easy AI agent support and a visible editor on the site to see how your changes will work out — we used it for our Money Magician landing page background.
  5. Squish — compresses GIFs and lowers the width and height (optional). It uses lossy compression, color reduction, and resizing until your GIF hits the target size.

Business ops — CRMs, invoicing, project management, and finance tools

  1. Twenty — an open source, AGPL-3.0 CRM built as a real alternative to Salesforce and HubSpot. Modern interface, full data ownership, self-host for free or use their managed cloud. Over 54,000 GitHub stars.
  2. Invoice Ninja — MIT-licensed, self-hosted invoicing and billing for freelancers and small teams. Recurring invoices, quotes, expenses, and a long list of payment gateways — run it yourself for the cost of a small VPS.
  3. Plane — an open source Jira, Linear, and ClickUp alternative for project and issue tracking. Cycles, modules, sprints, and a clean keyboard-driven UI — free to self-host with unlimited users.
  4. Akaunting — free, open source double-entry accounting: invoices, bills, expenses, banking, and reporting, self-hosted so your books stay yours.

Marketing & growth — landing page builders, email tools, analytics, and social media tools

  1. Drop-Kit — drop something in, get a post out. No design skills, no Canva tab open for twenty minutes, no account to make. Paste a link, a tweet, a photo, or some text — Drop Kit grabs the title, image, and source on its own and spits out a polished, platform-ready visual in seconds. 45+ templates (editorial, brutalist, retro pixel, device mockups, polaroids), every major format from Stories to YouTube thumbnails to X headers, one click to PNG or clipboard. No AI, no login, no friction.
  2. Silex — a free, open source, no-code website and landing page builder. Visual drag-and-drop editing, clean semantic output, and self-hostable if you want it on your own infrastructure.
  3. Listmonk — a self-hosted, open source newsletter and mailing list manager. Single Go binary, Postgres-backed, handles campaigns and segmentation — you just plug in an SMTP relay.
  4. Plausible — open source, privacy-first web analytics. Cookie-free, no consent banner needed, lightweight script — self-host it free or use their managed cloud.

AI & automation — self-hostable models, workflow builders, and agents

  1. Hermes Agent (by Nous Research, MIT license, released Feb 2026) is an autonomous AI agent with persistent memory — it lives on a server, remembers what it learns, builds reusable skills, and connects to Telegram, Discord, Slack, WhatsApp, Signal, and CLI from one gateway. It's grown explosively, from 40k to 188k GitHub stars between April–June 2026, and NVIDIA picked it as the reference runtime for their Nemotron 3 Ultra model.
  2. Warp is an AI-powered terminal — it went open source in May 2026 and is about reimagining the command-line experience with AI built in.
  3. Biome — a Rust-powered ESLint + Prettier replacement, now lints 10,000 files in ~0.8s (vs. ESLint's 45s).
  4. Claude-Mem — persistent context across sessions for every agent. Captures everything your agent does during sessions, compresses it with AI, and injects relevant context back into future sessions. Works with Claude Code, OpenClaw, Codex, Gemini, Hermes, Copilot, OpenCode and more. Claude-Mem has been silently working and supporting our own persistent memory across all our devices.

Skills & learning — free courses, communities, and resources worth bookmarking

  1. freeCodeCamp — a nonprofit, open source coding curriculum that's helped hundreds of thousands learn to code for free, from web dev basics through data science and machine learning.
  2. The Odin Project — an open source, project-based full-stack curriculum (Ruby on Rails or JavaScript) built by and for a large community of self-taught developers. No cost, no catch.
  3. roadmap.sh — the most-starred open source project on GitHub: community-built visual roadmaps for nearly every dev role and skill, plus guides and interview prep.
  4. Indie Hackers — a free community for bootstrapped, solo, and small-team founders swapping real revenue numbers and playbooks, no hype. Owned by Stripe, still free to join.

Infrastructure — hosting, databases, and deployment options that won't break the bank

  1. Coolify — an open source, self-hostable PaaS that turns any VPS into your own Heroku, Vercel, or Netlify. 280+ one-click app deploys, automatic SSL, no vendor lock-in. Over 55,000 GitHub stars.
  2. Supabase — the open source Firebase alternative: Postgres database, auth, storage, and realtime APIs bundled in one self-hostable package.
  3. Dokploy — a lighter, faster-to-set-up open source alternative to Coolify. Same push-to-deploy idea on your own server, leaner footprint — a good fit if you're running just one or two apps.
  4. Cloudflare Uptime — our own build: a self-hosted uptime monitor that runs entirely on Cloudflare's free tier, Workers for the checks, D1 for the data, plus a public status page your users can actually see. No vendor lock-in, MIT licensed, source on GitHub if you want to run your own.