Launch a startup for €15 a month

That pays for the whole public side of an AI startup. Three decisions keep it that small: inference on the user’s device, SQLite instead of a managed database, and deploys that need no standing second server.

What runs on a 2 GB VPS

One Caddy server terminates TLS for every hostname and proxies each to a process on the same machine. Each service keeps its state in its own SQLite file, so there is no database server to run or pay for.

The monthly bill, line by line

“One small VPS” is three line items, and the IP address is more than half the price of the machine. Scaleway bills a flexible IPv4 by the hour, attached or not.

Why the bill does not grow with users: the model runs on their device

Klar classifies mail on the user’s own device, so a new user adds nothing to our server or our bill. The model is a file of a few hundred MB inside the Mac app, the App Store carries that download, and our server never sees a user’s message.

A transformer model in 2 GB of RAM

The homepage demo runs a Klar model inside the website’s Node process, and that process does not swap. Half of its memory is the model file mapped from disk, which the kernel can drop and read back under pressure.

SQLite and Litestream instead of a managed database

Each database is a file, and Litestream streams every change to Object Storage, so a dead box loses at most about a minute of database writes. Each database is also archived monthly and kept for a year. The password vault, a database plus files, is snapshotted with btrfs every 15 minutes.

Deploys without a standing second server

A rebuild creates a second VPS for a few minutes, restores it from Object Storage, then moves the IP address to it. That is why the IPv4 is flexible: the address outlives the machine. The swap shows as a blip of about a second, and the old box is destroyed right after.

Where one box breaks

• SQLite with Litestream allows one writer, so there is one active node.
• 2 GB is the ceiling for now. The next step, a DEV1-M with 4 GB at €14.74, more than doubles the compute line.
• One machine is one failure domain: a hypervisor fault means minutes of downtime while we restore.

Start with one box

Put everything on one small VPS until a measurement says otherwise. The free Klar Mac app is the model side of this: it sorts Apple Mail on your Mac, and nothing it reads reaches the server above.

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