Multi-company Accounting SaaS

The problem

Businesses that run several companies needed one accounting platform that follows Vietnamese accounting rules (Circular 99/2025), produces consolidated reports across companies, and can be trusted by the accountants who use it every day. In accounting, a half-posted batch or an edit to a closed period is not a bug; it is a wrong set of books.

What I built

I was the top contributor, from the first commit, in a three-engineer team, from 2025 to September 2026, when the platform was handed over:

• Consolidated financial reporting under Circular 202, end to end, with intercompany elimination and Excel export.
• Fixed assets, loans and bank reconciliation modules.
• Safe posting — atomic batch posting and period locking.
• CI/CD from GitHub Actions to GHCR, with Watchtower updating the containers on the client's own servers.

How it works

The platform is multi-company: each company keeps its own books, and consolidation combines them while eliminating intercompany transactions, so the group report does not count the same money twice. Posting a batch of journal entries is all-or-nothing: either every entry lands or none does, so the ledger never ends up half-updated. Once a period is closed it is locked, and entries can no longer be posted into it. Releases are built by GitHub Actions and pushed to GHCR; Watchtower on the client's servers picks up new images, so deployment runs on the client's infrastructure.

Outcome

The platform is used daily by 20 accountants, covering journal entries, trial balance, cash vouchers, customers and the financial reports built to Vietnamese standards. It was handed over in September 2026.

Stack

• React frontend
• REST API
• PostgreSQL
• Docker images built with GitHub Actions, published to GHCR, deployed with Watchtower