Silo
Silo is a free, open-source, self-hosted HTTP server for Gradle remote build caching.
What Silo is
Silo is a free, open-source, self-hosted HTTP server for Gradle remote build caching. It speaks the Gradle build cache protocol and is intended to replace the end-of-life Gradle Remote Build Cache Node. Gradle clients can use its GET, PUT, and HEAD methods to retrieve, upload, and check cached artifacts. Silo currently stores cache files on a filesystem; S3 and Google Cloud Storage backends are listed as future work. Cache administration includes least-recently-used eviction, time-to-live settings, byte and entry limits, and reserved free-space thresholds. Authentication supports HTTP Basic and OIDC/Bearer credentials with read-only or read-write role mapping. The project provides Prometheus metrics, JSON-structured logs, health and readiness endpoints, and a live statistics stream. A single-page dashboard is available at `/admin`, with a simulated-data demo that needs no installation or backend. Silo runs on Linux, requires JVM 21 or later, and is distributed as a fat JAR or multi-architecture Docker image for linux/amd64 and linux/arm64. It is alpha and pre-1.0 software.
Good
- Free self-hosted Gradle cache
- Supports filesystem storage
- Read-only and read-write role mapping
- Prometheus metrics and health endpoints
- Fat JAR and multi-architecture Docker image
Watch out
- Requires JVM 21 or later
- S3 and GCS remain roadmap items
- Project is alpha and pre-1.0
- Only latest v0.x release gets security fixes
Who it suits
Silo suits Gradle teams wanting a self-hosted remote cache on Linux. It is also aimed at operators who need configurable retention, authentication, and monitoring.
Verdict
Silo provides a focused, self-hosted Gradle cache with filesystem storage, role-based authentication, retention controls, and operational monitoring. Its alpha status and unfinished storage backends matter when planning a deployment.
Plans and prices
From Silo's own pricing page, checked 8 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Silo | Free | Self-hosted Gradle build cache · Apache-2.0 · filesystem storage |
The facts
Each one read from Silo's own pages, with the date it was checked.
What it does
- Admin dashboard
- Silo includes a single-page admin dashboard at /admin, and its live demo runs with simulated data without installation or a backend.checked 8 Oct 2026
- Authentication
- Silo supports HTTP Basic and OIDC/Bearer authentication with read-only and read-write role mapping.checked 8 Oct 2026
- Cache management
- It supports LRU eviction, TTL, byte and entry caps, and reserved free-space thresholds.checked 8 Oct 2026
- Current status
- The project describes itself as alpha and says S3/GCS backends, compression, and replication remain open work.checked 8 Oct 2026
- Deployment
- Silo is distributed as a fat JAR and a multi-architecture Docker image for linux/amd64 and linux/arm64.checked 8 Oct 2026
- Implementation
- Silo is written in Kotlin using Ktor and requires JVM 21 or later.checked 8 Oct 2026
- Monitoring
- Silo provides Prometheus metrics, JSON-structured logs, health and readiness endpoints, and a live stats stream.checked 8 Oct 2026
- Protocol
- It supports the Gradle HTTP build cache protocol methods GET, PUT, and HEAD.checked 8 Oct 2026
- Purpose
- Silo is a self-hosted HTTP server that speaks the Gradle build cache protocol and replaces the end-of-life Gradle Remote Build Cache Node.checked 8 Oct 2026
- Release integrity
- The security policy says release artifacts are cosign-signed, the fat JAR has a SHA-256 checksum, and every release includes a CycloneDX SBOM.checked 8 Oct 2026
- Security
- The project says it has no phone-home telemetry or accounts and supports atomic writes with crash recovery.checked 8 Oct 2026
- Security support
- Silo is pre-1.0, and only the latest v0.x release receives security fixes; the policy promises acknowledgement within 3 business days and initial assessment within 7 business days.checked 8 Oct 2026
- Storage
- Filesystem storage is implemented, while S3 and GCS are listed as roadmap items.checked 8 Oct 2026
