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Cybersecurity · head to head

Authelia vs Nix

Authelia logo

Authelia

Cybersecurity

Open-source authentication and two-factor portal for reverse proxies

From
Free
Free plan
Yes
Full reviewWebsite
Nix logo

Nix

Developer Tools

Purely functional package manager and the NixOS distribution built on it, for byte-reproducible environments

From
Free
Free plan
Yes
Full reviewWebsite

The short version

  • Each has a real cost: Authelia depends on a reverse proxy: it is not a standalone identity provider; Nix the Nix language is lazy, dynamically typed and poorly documented, and its error messages frequently point at the wrong expression, so debugging a failing build is a skill that takes months rather than days to acquire.
  • They diverge on capability: Authelia covers Reverse proxy integration, Nix covers Content-addressed store.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Authelia and Nix actually diverge.

Attributes where Authelia and Nix differ
AttributeAutheliaNix
PlatformsDocker, Kubernetes, Linux, Self-hostedLinux, macOS, Windows (via WSL)
CategoryCybersecurityDeveloper Tools

Identical on both: starting price (Free), pricing model (Open source, no licence fee), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Authelia

  • Reverse proxy integration
  • Two-factor authentication
  • Access control rules
  • Lightweight backends

Only in Nix

  • Content-addressed store
  • Declarative system configuration
  • Atomic upgrades and rollback
  • nix develop shells
  • Flakes
  • Nixpkgs
  • Binary caches
  • Home Manager

What people use each for

The jobs each tool is most often brought in to do.

Authelia

  • Putting a login and 2FA in front of self-hosted services that have nonenot Nix
  • Adding SSO across a small set of internal tools without a full identity platformnot Nix
  • Home and small-team infrastructure behind a single reverse proxynot Nix

Nix

  • A team that wants every developer and CI runner to use byte-identical toolchains without shipping a container for local worknot Authelia
  • Reproducing a research computation or a build years later from a pinned commit rather than a written recipenot Authelia
  • Managing a fleet of Linux servers declaratively with atomic rollback if a deployment breaks a servicenot Authelia
  • Building minimal container images from precise dependency closures instead of a base image plus a package managernot Authelia

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Authelia

  • Depends on a reverse proxy: it is not a standalone identity provider
  • Configuration is YAML-first with no administrative interface, so changes mean editing files
  • Not a full IAM: user management, provisioning and federation are limited compared with Keycloak
  • Scales poorly as an organisation-wide identity solution, which is not its target

Nix

  • The Nix language is lazy, dynamically typed and poorly documented, and its error messages frequently point at the wrong expression, so debugging a failing build is a skill that takes months rather than days to acquire.
  • Flakes are the way essentially everyone uses Nix in 2026 and are still formally an experimental feature behind a flag, meaning tutorials, official documentation and real practice disagree with each other constantly.
  • Anything that expects a conventional Linux filesystem layout breaks: prebuilt binaries, language package managers that download their own toolchains, and proprietary vendor installers all need patching or an FHS-compatible wrapper.
  • Project governance has been publicly fractious, producing the Lix fork and the separately funded Determinate Systems distribution, so a new adopter now has to choose which Nix before they can start.
  • The /nix/store grows without bound until you garbage collect, and on a developer laptop with several pinned nixpkgs revisions it routinely reaches tens of gigabytes.

Pricing, plan by plan

Authelia

Free
  • AutheliaFree
    • Full functionality
    • No usage limits
    • Community support

Nix

Free
  • Nix and NixOSFree
    • LGPL-2.1 licensed, no commercial tier
    • Public binary cache at cache.nixos.org
    • Community support via forum, Matrix and GitHub

Which should you pick?

Choose Authelia if

  • You need reverse proxy integration.
  • You want to start without paying.
  • You work on Docker, Kubernetes, Linux, Self-hosted.
  • You also want two-factor authentication.
Authelia review

Choose Nix if

  • You need content-addressed store.
  • You want to start without paying.
  • You work on Linux, macOS, Windows (via WSL).
  • You also want declarative system configuration.
Nix review

Questions people ask

Is Authelia or Nix better?
Neither clearly leads. Authelia starts at Free and Nix at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Authelia or Nix?
Authelia starts at Free and Nix at Free.
Does Authelia or Nix run on more platforms?
Authelia runs on Docker, Kubernetes, Linux, Self-hosted. Nix runs on Linux, macOS, Windows (via WSL).
Can I use Authelia for free?
Both have a free tier, so you can try either at no cost before committing.
What is Authelia best used for?
Authelia is most often used for putting a login and 2fa in front of self-hosted services that have none, adding sso across a small set of internal tools without a full identity platform, home and small-team infrastructure behind a single reverse proxy. Of those, putting a login and 2fa in front of self-hosted services that have none and adding sso across a small set of internal tools without a full identity platform are not what Nix is typically brought in for.
What can Authelia do that Nix cannot?
Authelia covers Reverse proxy integration, Two-factor authentication, Access control rules, Lightweight backends. Nix covers Content-addressed store, Declarative system configuration, Atomic upgrades and rollback, nix develop shells.

Answered from the vendors’ own pages

Authelia: Is Authelia free?

Yes, open source with no licence fee.

Nix: Do I have to run NixOS to use Nix?

No. The package manager runs fine on any Linux distribution and on macOS, and most teams start there with development shells rather than converting their servers.

Authelia: Does Authelia need a reverse proxy?

Yes. It integrates through forward authentication with Nginx, Traefik, Caddy or HAProxy rather than sitting in front of traffic itself.

Nix: Is Nix a replacement for Docker?

It solves an adjacent problem. Nix reproduces the contents of an environment exactly; Docker distributes an image. Many teams use Nix to build the image.

Authelia: Authelia or Keycloak?

Authelia is far lighter and aimed at protecting self-hosted services behind a proxy. Keycloak is a full identity and access management platform, and much more to run.

Nix: Are flakes safe to use in production?

They are used in production widely and are stable in practice, but they remain officially experimental, which means the interface can still change and documentation is split.

Nix: What is Lix and should I care?

Lix is a community fork of the Nix implementation created after governance disputes. It is largely compatible; the practical impact is that you must decide which implementation your team standardises on.

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