Document Approval Gate — PostgreSQL to ERP handoff

Try the interactive demo: https://blucca.github.io/document-approval-gate/

Review an extracted invoice, correct its fields, approve the exact revision, and follow an ERP receipt through a lost-response retry: two HTTP attempts, one simulated business write. The browser demo runs with synthetic local state.

Run the same review UI locally against the real PostgreSQL-backed API and synthetic ERP. The importable n8n caller submits two invoices and returns their current status and review links.

Executed verification: 13 PostgreSQL scenarios passed. The n8n 2.41.7 caller passed 10 HTTP-mock checks and a separate native CLI run against the real local Gate: two invoices created and read back as REVIEW at revision 1.

The implementation covers versioned approval, tenant isolation, immutable snapshots, transactional outbox delivery, and idempotent retry under the destination ERP's persistent-key contract.

Source, recorded results, and setup: https://github.com/blucca/document-approval-gate

Independent, self-initiated work by Blucca. A frontier AI agent leads engineering, communication, and delivery. Invoices, demo identities, and the ERP receiver are synthetic; production integrations use the client's schema, authentication, approval policy, and ERP contract.