Cachix vs FosterStack

Cachix hosts Nix binary caches so teams can share binaries across CI, development, and deployment environments. Its CLI can push binaries, watch a Nix store, and configure Nix to use a cache. The service says its optimizations speed up cache roundtrips, while Cloudflare CDN provides performance and unlimited bandwidth on all plans. When a cache reaches its storage limit, least-recently-used entries are removed; Cachix says it sends a warning email at 85% of that limit. Documentation includes CI guides for GitHub Actions, Buildkite, CircleCI, GitLab CI, Hercules CI, Hydra, and Travis CI. Cachix Deploy uses a pull model to deploy continuously to Nix profiles such as NixOS, nix-darwin, and Home Manager. Teams can assign read or write access, revoke tokens, and require a token for private cache reads and writes; cache entries are signed. Enterprise options include on-premise or self-hosted deployment, SSO, SLA, dedicated premium support, custom deployment, and audit logs. Cachix offers a free plan and a 14-day trial. Listed Starter, Standard, and Pro plans have prices available by contacting Cachix.

FosterStack is a self-hosted remote build cache server intended as a replacement for Develocity Build Cache Node. It supports Gradle and the Apache Maven Build Cache Extension remote HTTP mode, although Maven acceptance coverage is in progress. Size-capped LRU eviction frees space for new entries. HTTP Basic Auth over TLS uses constant-time credential comparison, and credentials are not logged. Prometheus metrics and a read-only status page report hit rates and cache size against its cap. Deployment options are a Docker image or static binary; release binaries are available for Linux and macOS on amd64 and arm64. Windows is not built or planned. The MIT-licensed core has signed releases with SLSA provenance, and security patches are included in the free tier. The maker says the free core makes no outbound connections and collects no telemetry or usage data. FosterStack identifies the product as v0.1 and says nobody outside its own work is yet running it in a production build pipeline. The full self-hosted server is free. Team, Business, and Compliance plans are described but not yet available, with listed prices of $49.00 per month, $199.00 per month, and $499.00 per year, respectively.