Cachix

Cachix is a hosted service for Nix binary caches, sharing build outputs among development, CI, and deployment systems. It suits Nix-based teams that want cache administration and deployment in one product. The strongest case is a Nix workflow that values integrated controls; storage ceilings and custom-priced plans require closer fit analysis.

Overview

Launched in 2018 by Enlambda OÜ, Cachix focuses on moving Nix binaries between the environments that build and run them. Its scope is narrower than a general artifact repository, but that specialization is useful when Nix is already central to your toolchain. Enterprise customers can choose on-premise or self-hosted deployment, SSO, SLAs, dedicated premium support, custom deployment, and audit logs.

Key features

The Cachix CLI pushes binaries, watches a Nix store, and configures Nix to consume a cache. That covers publishing, monitoring, and client setup in one command-line workflow. Cachix says its optimizations improve binary-cache round trips, while Cloudflare CDN caching and unlimited bandwidth apply across plans. Storage, rather than transfer volume, is the practical quota to manage.

At capacity, least-recently-used entries are removed, with an email warning at 85% of the limit. Automatic eviction keeps service running without constant cleanup, but teams that depend on older build outputs may need a larger allowance or retention discipline. Retention rules are supported.

Guides cover GitHub Actions, Buildkite, CircleCI, GitLab CI, Hercules CI, Hydra, and Travis CI. Cachix Deploy continuously updates NixOS, nix-darwin, and Home Manager profiles through a pull model. Agent counts vary substantially by plan, so deployment-heavy users should size the subscription around that ceiling.

Per-cache permissions let team members receive read or write access, and tokens can be revoked at any time. Private reads and writes require a token; cache entries are signed with a managed or self-signed key. Support channels include live chat, email, GitHub issues, and a service-status page. Cachix says it acknowledges vulnerability reports within five business days and targets confirmed fixes within 90 days; it does not run a paid bug bounty.

Pricing

Cachix uses a freemium model with a free plan and a 14-day trial. Published paid plans use custom pricing, so contact [email protected] for a quote.

Starter

Starter includes 50 GiB of storage, unlimited bandwidth, Cloudflare CDN caching, and Cachix Deploy for 100 agents. It is the sensible starting point for a small Nix team or modest deployment fleet, but the smallest storage allowance leaves less room for long-lived artifacts.

Standard

Standard raises storage to 250 GiB and deployment capacity to 200 agents, retaining unlimited bandwidth and CDN caching. It adds a one-hour Nix consultation, making it a better fit for teams that need occasional implementation guidance and more cache headroom.

Pro

Pro provides 1,500 GiB, 1,000 deployment agents, unlimited bandwidth, CDN caching, and a one-hour Nix consultation. Its substantially higher limits suit large organizations with broad deployment estates; smaller teams would be paying for capacity they may not use.

Platforms

Cachix is offered through API and web interfaces and supports Linux, macOS, and Windows. Self-hosted deployment is available, including enterprise arrangements, which matters for organizations that cannot place cache infrastructure entirely in a hosted service.

Who it's for

Choose Cachix when your builds use Nix and you want shared binary caching, documented CI integrations, controlled private access, and Nix profile deployment in one service. It is less compelling for projects that need a language-agnostic artifact store, or for teams unwilling to manage LRU eviction and custom-priced capacity.

Pros and cons

Pros

Nix-specific CLI and CI guidance cover the full path from build output to deployment.

Unlimited bandwidth and Cloudflare CDN caching on every plan avoid transfer-based throttling.

Granular read/write permissions, revocable tokens, and signed cache entries support private workflows.

Self-hosted and enterprise options accommodate stricter operational requirements.

Cons

All paid plan prices are custom, making budgeting harder before contacting sales.

Storage limits can trigger LRU eviction, risking removal of older artifacts.

Deployment-agent allowances may constrain larger fleets on Starter and Standard.

Alternatives

Bitrise is a better fit for mobile-focused teams needing Android and iOS build automation with a free Hobby plan. EngFlow Remote Caching suits teams seeking a free remote-cache option with one machine and 32 CPU cores on Linux, or enterprise arrangements. BuildFetch Cache is worth considering for self-hosted or web cache storage with explicit free quotas and 45-day LRU retention.

Ccache is the straightforward free choice for single-file compilation caching across major desktop platforms. NativeLink targets self-hosted distributed scheduling and remote caching across build systems. cachepot is open-source software without hosted plans. MozJPEG is an open-source JPEG encoder rather than a general build-cache service. Vercel is aimed at web delivery and deployment, with a free Hobby plan and a $20.00 monthly Pro plan.

For broader comparisons, see Build Cache Software and Artifact repository software.

Verdict

Cachix is a strong choice for Nix-centered teams that want binary caching, CI guidance, access control, and profile deployment together. Choose it for that integrated Nix workflow; look elsewhere if you need transparent paid pricing, very large retention guarantees, or a general-purpose artifact platform.