Show HN: Scaledger, an Open Source Ledger API in GraphQL and Postgres

Scaledger is double-entry accounting database with a typed GraphQL API, supporting:

* Immutable entries

* An API introspected directly from a PostgreSQL schema

* GraphQL subscriptions for real-time updates

It does so with a Node server written in TypeScript (with the excellent Postgraphile library), and a PostgreSQL database.

Scaledger is designed to be used as a service for recording transactions (called postings) between accounts, and reporting their balances through an entity called ledger. This is particularly useful when you have to track the balances for thousands, or even millions of users. You've taken a payment, but now you've got to keep track of who is owed what? Scaledger is good for that.

The basics are pretty simple, but I've tried to be thoughtful about the kinds of details that most startups get wrong when they're trying to do things like track user balances: using floats for money, making transactions mutable, etc.