Volt

Zero-Config Universal Compiler Cache

Volt is a transparent build cache for Unix compilers. It uses LD_PRELOAD to trace the exact files a build reads and writes, then restores identical outputs with reflink copy-on-write or hard-links on the next invocation. No wrapper scripts, no compiler plugins, no centralized daemon.

View on GitHub Read the spec

bash

$ volt run gcc -o main main.c

How it works

Three mechanisms. No configuration files.

Syscall interception

Volt injects a thin shim via LD_PRELOAD. It intercepts open, openat, execve, and close to record every dependency the compiler touches, without recompiling or relinking the toolchain.

open / openat / execve / close hooks
Deterministic read-set / write-set tracking
No compiler modifications

Reflink copy-on-write

When the filesystem supports FICLONE (APFS, XFS, Btrfs), Volt restores cached outputs by creating a copy-on-write clone. The data blocks are shared until something writes, so no bytes are copied.

FICLONE / clonefile on CoW filesystems
Hard-link fallback on ext4
Content-addressed artifact store

Local P2P sync

Volt announces and discovers peers on the local network using mDNS and multicast. Warm cache entries are served over the LAN, so the next engineer in the office starts with a hot cache.

mDNS service discovery
Multicast cache announcements
LAN-only, no external egress

Execution tree map

Every invocation is reduced to a canonical signature: the sorted list of files read, the files written, their content hashes, and the command line. Re-run the same inputs and Volt replays the output tree without invoking the compiler again.

{
  "signature": "sha256:9f4e2c…",
  "reads": [
    "main.c",
    "stdio.h",
    "stdlib.h",
    "libm.so"
  ],
  "writes": ["main"],
  "cache": "hit",
  "restore": "reflink"
}

Pricing

Pay for flow state, not compute.

Developer Velocity

$49/ user / mo

For individual developers and small teams who want their local builds to disappear.

Unlimited local cache
LD_PRELOAD tracing
Reflink + hard-link restore
macOS & Linux support

Start building faster

Enterprise Grid

$149/ user / mo

For engineering organizations that treat CI minutes as a top-line cost.

Everything in Developer Velocity
Local P2P cache sharing
CI compute spend optimizer
Priority support & SLA

Talk to sales

Technical FAQ

Edge cases and common questions.

Open source

No account required. Clone it and compile.

Volt is built for engineers who want their tools to get out of the way. The repo is public on GitHub.

Open the repository

github.com/Blu3Ph4ntom/volt