# monorail.dev

Local-first dev environments that boot in <200ms. A drop-in replacement for the Docker Compose file you've been adding services to since 2019. Single binary. Zero daemon. npx monorail up and you're done.

## Why monorail?

Most teams ship a docker-compose.yml that's grown to 14 services, takes 4 to 11 minutes to boot, eats your laptop's battery, and breaks differently for every new hire.

monorail replaces it with a single 8MB binary that:

• Boots a 14-service stack in under a second, on a fresh machine.
• Reuses native processes where it can, falling back to micro-VMs only when isolation matters.
• Hot-reloads service config without bringing the stack down — including database schemas.
• Ships with a declarative monorail.toml that's diffable, reviewable & lints in CI.
• Replays your team's stack from a single git commit. New hires onboard in 4 minutes.

## Install

## Benchmarks

Cold-start time of the same 14-service stack (Postgres, Redis, Kafka, NATS, Mailhog, Minio, Localstack, two Node APIs, three Go services, a Python worker, a Rust binary), on an M2 MacBook Pro, fresh boot, no cache.

We publish the full benchmark harness, the raw 200-run dataset, and the methodology in /bench. Run it on your own hardware:

# clone, run, compare against your existing setup
git clone https://github.com/monorail-dev/bench
cd bench && ./run.sh --vs docker-compose

## How it works

monorail reads a single monorail.toml and decides — per service — whether to run it as a native process, a Firecracker microVM, or in a shared lightweight sandbox. Most things run native. Only what needs isolation gets virtualised.

# monorail.toml — committed to your repo
[stack]
name = "billing-api"
profile = "dev"

[services.postgres]
image = "postgres:15-alpine"
isolation = "sandbox"      # shared sandbox · cheap
data = "./.monorail/pg"     # persistent across boots

[services.api]
cmd = "pnpm dev"
isolation = "native"        # native process · fastest
depends_on = ["postgres", "redis"]
port = 3000

[services.worker]
cmd = "go run ./cmd/worker"
isolation = "microvm"       # Firecracker · for messy deps

## Pricing

monorail is open-source & free forever for individuals. The team plan adds shared remote stacks, ephemeral PR environments, and audit logs.

## Changelog · recent

## Built in the open · join us

"We replaced a 412-line docker-compose.yml with a 38-line monorail.toml on a Friday afternoon. Boot time fell from 11 minutes to 0.2 seconds. The team has not stopped talking about it."
— Eilidh K., staff eng · @ stripe

monorail is built by a team of seven, fully in the open, on GitHub. We ship every other Friday. Issues are triaged daily. Every PR gets a human review.

• ★ Star on GitHub — github.com/monorail-dev/monorail
• # Join the Discord — 8,400 devs, 4 maintainers on call
• ↪ Subscribe to the changelog — one email per ship
• ♥ Sponsor a maintainer — github.com/sponsors

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