Introduction

onebase is a reactive backend you run yourself. You write your backend as TypeScript functions, store data in a typed document database, and clients subscribe to queries that update live when the data changes. It all ships as one executable file.

// onebase/messages.ts
export const list = query({
  args: { channel: v.id("channels") },
  handler: (ctx, { channel }) =>
    ctx.db.query("messages").withIndex("by_channel", (q) => q.eq("channel", channel)).collect(),
});

export const send = mutation({
  args: { channel: v.id("channels"), body: v.string() },
  handler: (ctx, args) => ctx.db.insert("messages", args),
});

// In your React app: re-renders whenever anyone sends a message.
const messages = useQuery(api.messages.list, { channel });

#Why onebase

onebase follows Convex's programming model and API, and makes different trade-offs:

• Small. One Bun process with SQLite. It uses about 40 MB of memory at startup and needs no separate database server.
• Node and npm everywhere. Queries, mutations and actions all run in Bun, so any npm package works in any function. There is no "use node" split.
• One file to deploy. Copy the binary to a server and run it. The functions can sit next to it in a folder, or be compiled into it along with your frontend.
• Hard to misuse. Errors explain how to fix the problem, .filter() picks indexes automatically, and onebase doctor catches common mistakes. This matters when an LLM writes the code.
• Grows with you. Start on SQLite. When you need several instances, switch to Postgres, MySQL or Turso with one flag.

#What's included

#When to use something else

onebase is a young project. Use Convex if you want a managed service and a team supporting it. Use onebase if you want to own the whole stack, run it on a small VPS or your own hardware, or need full Node.js in every function.

Next: Quick start.