The accounting platform you can program
Accurate books.
Fully programmable.
An event-driven ledger, a TypeScript runtime, and a dashboard that's actually yours. Built for ambitious startups.
Now actively onboarding design partners.
Your accounting software wasn't built for you.
You wired up three integrations to pull in data. You wrote a Python script to reconcile Stripe payouts. You built a Google Sheet that calculates deferred revenue the way it actually works at your company. Your accounting setup is a tangle of spreadsheets, integrations, and Notion docs.
The problem isn't that you've outgrown your accounting software. The problem is that it was built for a bookkeeper recording transactions, not for the kind of startup that would rather automate the boring parts than click through them.
Backfill untangles it all as the unified system of record.
Connect. Automate. Program the rest.
Connect your banks and credit cards
Live transaction feeds from every account, daily. Reconciliation that stays current without spreadsheets.
Backfill keeps the books
Categorization, matching, and posting run automatically. The inbox surfaces only what needs you.
Program the rest
Hit a wall? Add a custom entity, a custom view, an approval flow, an event hook, all in TypeScript, on the same runtime.
Most accounting tools assume you'll click. Backfill assumes you'll code.
Custom entities, event hooks, custom views, automations, and much more. All in TypeScript, on the same runtime our own integrations are written against.
A typed developer SDK. A REST API for every shipped resource. An MCP server so your AI tools wire straight in. Build the workflows and automations you always needed for your back office on a solid foundation.
import { Backfill } from "@backfill-io/sdk";
const bf = new Backfill({
apiKey: process.env.BACKFILL_API_KEY,
});
await bf.invoices.create({
customerId: "cus_4f9a",
currency: "USD",
lines: [
{
description: "Pro plan — March",
quantity: 1,
unitAmount: 9900,
},
],
idempotencyKey: "inv-2026-03-cus_4f9a",
});Connect every tool your business runs on.
Banks, payment processors, billing systems, e-commerce, payroll, your warehouse. Webhook ingest, scheduled syncs, idempotent imports, and a UI that makes the resulting books easy to review.
We're shipping connectors as fast as we can. Stripe is live today, with more landing every month. The integrations our customers need most go to the front of the line.
And when we haven't built it yet? You can. Every connector is written on the same scripting runtime as everything else you'll customize: Same TypeScript, same primitives, same ergonomics our own Stripe connector uses.
One inbox. Every transaction that needs you.
The inbox does the boring part: Extracting vendor, amount, line items, tax, and proposing categorization. You confirm what posts. The keyboard does the work.
The goal is inbox zero, not staring at transactions at 11pm.
Everything else you need to run your books.
Posting rules
Set rules once. Transactions post to the right GL accounts automatically. Override with code when defaults aren't enough.
Banking
Connect your bank and credit cards. Auto-import. Reconcile against the books in one view, not a spreadsheet.
Real reports, always current
P&L, balance sheet, trial balance. Hierarchical, drill-down, exportable. No quarter-end fire drills.
Audit trail by construction
Every document versioned, every action attributed, every reversal accounted.
Safe to automate with a solid foundation.
Backfill enforces the guardrails so you can move fast without breaking the books.
Sandboxed extensions
Your code runs in a TypeScript sandbox scoped to your books.
Guaranteed posting
Every transaction reaches the ledger through one audited pipeline. Nothing slips through.
Full audit trail
Every change versioned, every action attributed, every reversal accounted.