15:I[981,["658","static/chunks/658-a698693f56d0116a.js","183","static/chunks/183-6beeeb801c274aaa.js","474","static/chunks/app/%5Btype%5D/layout-631c4730b83c8223.js"],"Posts"] 16:T574,Hey HN,

I'm a solo founder running a service business through an Estonian e-Residency company (OÜ). Every time I invoiced a client in another EU country, I had to manually check if reverse charge applies, validate their VAT number on VIES, and figure out the correct tax treatment. I got tired of Googling the same rules over and over, so I built the tool I wanted.

Invoxo automatically determines the correct VAT treatment for each invoice based on seller/buyer countries, VAT registration status, and buyer type. It covers:

- VIES VAT number validation (real-time, with proof retention) - Reverse charge auto-detection for EU B2B - OSS handling for B2C digital services - Immutable tax records locked at issuance

The tax engine routes every invoice through a regime-specific decision system — no hardcoded rules in the UI layer. Tax payloads are versioned and hashed for audit.

It's built for service businesses only — no goods, no customs, no margin schemes. That constraint keeps the tax logic correct rather than approximately correct.

Stack: Laravel, TaxRegimeRouter that isolates each regime's decision logic, treatments, and payload schemas.

14-day free trial, plans from €19/month.

https://invoxo.eu

Happy to answer questions about EU VAT edge cases or the architecture.17:T4b6,Hi HN — I just open-sourced Hibana and hibana-agent.

Hibana is an Affine MultiParty Session Types (MPST) runtime for Rust.

It targets protocol drift in distributed systems. Instead of maintaining separate hand-written state machines in each component, you define interaction once as a global choreography and project role-local behavior at compile time. At runtime, only valid protocol transitions are executable, so invalid moves such as skipping, reusi

Trust Spanning Protocol (TSP) Specification