Kai A. Hartung

Kai A. Hartung

Open Source did not fail in AI.

Open Source did not fail in AI.

Open, capable, sovereign: in AI you get to pick two. The frontier models are proprietary and revocable, the open ones you cannot run or cannot match, and even Europe's champion runs on chips it will never make. Sovereignty is not the model you pick. It's the weakest layer beneath it.

Starlight

Starlight

Documentation sites on Astro, with self-hosted full-text search built in rather than bolted on. Mix React, Vue, or Svelte components in one site. Still pre-1.0 after three years.

VitePress

VitePress

Vue and Vite powered documentation sites. Markdown in, static HTML out, with a build fast enough that large sites stay pleasant. The stable line has been quiet for about a year.

Sphinx

Sphinx

The documentation generator behind Python itself. One plain-text source builds a website, a PDF, and an API reference pulled from your code. reStructuredText is the learning tax.

Docusaurus

Docusaurus

Documentation as code. Your content stays as Markdown in your own Git repo and ships as static HTML you host anywhere. Search is the one piece you still solve yourself.

NSD

NSD

An authoritative-only DNS server from the Dutch non-profit NLnet Labs, run by DNS root servers and many TLDs. Minimal attack surface by design, BSD-3. It serves zones only, not recursion.

Unbound

Unbound

A validating recursive DNS resolver from the Dutch non-profit NLnet Labs. Resolve from the root servers yourself, so no public resolver sees your lookups. A focused resolver, not a full server.

BIND 9

BIND 9

The reference DNS implementation much of the internet runs on, governed by the non-profit ISC, not a company. Authoritative and recursive, MPL-2.0. Configuration is manual and zonefile-driven.

PowerDNS

PowerDNS

Carrier-grade open source DNS used by ISPs and telcos: authoritative server, recursor and load balancer in one GPLv2 codebase. EU-owned via Open-Xchange. The management UI and support are a paid tier.

AdGuard Home

AdGuard Home

A self-hosted DNS ad-blocker with encrypted DNS and DHCP built in, blocking ads across every device. Auditable GPL code that phones nothing home. A modern sinkhole, not a full authoritative server.

Pi-hole

Pi-hole

A network DNS sinkhole that blocks ads and trackers for every device, with no client software. Runs fully offline, so its US parent never sees a query. A focused ad-blocker, not a full DNS server.

Technitium DNS Server

Technitium DNS Server

A self-hosted DNS server that works as both a privacy resolver and a full authoritative server. Encrypted DNS, DNSSEC, clustering and SSO are all free, with no paid tier. Development rests on one maintainer.

Passbolt

Passbolt

A Luxembourg-based, OpenPGP password manager for teams sharing credentials. EU jurisdiction keeps it clear of the US CLOUD Act. SSO, directory sync and audit logs are paywalled.

KeePassXC

KeePassXC

An offline password vault with no server and no vendor cloud. Credentials live in a local encrypted file you control. No central administration, so offboarding and backups are yours.

OpenZiti

OpenZiti

Apache-2.0 zero-trust overlay you embed into the application itself. The whole stack, controller included, is self-hostable with no capability paywall. NetFoundry sells only managed hosting and support.

Headscale

Headscale

BSD-licensed control server that runs official Tailscale clients on coordination infrastructure you host, no proprietary cloud. Volunteer-maintained; no GUI, RBAC, or commercial support.

NetBird

NetBird

WireGuard mesh VPN with a control plane you self-host, the EU-sovereign answer to Tailscale. OIDC SSO included; active-active HA, SCIM, and SIEM streaming are commercial.

CrowdSec

CrowdSec

MIT-licensed collaborative intrusion prevention that blocks malicious IPs from your logs and shares the signals network-wide, so every user gains herd immunity. Premium blocklists are paid.

Security Onion

Security Onion

Source-available (ELv2) network security monitoring on Suricata, Zeek, and the Elastic Stack. Self-hostable and airgappable; SSO and disk encryption require the paid Pro tier.

Lightdash

Lightdash

Open-core, dbt-native BI that turns metrics and dashboards into version-controlled code. The MIT core is self-hostable; SSO and fine-grained RBAC sit behind the paid tier.

Redash

Redash

A SQL-first query, dashboard, and alerting tool with 50+ data connectors and no paid tier. Databricks abandoned the hosted service in 2021; the community rebuilt it.