Developers · API
Build on RegNexus Books.
A deterministic financial data model you can build on with confidence — scoped keys, signed webhooks and verifiable provenance. Connect without surrendering control.
● API & Webhooks — available on scoped, disclosed readiness
Principles
Powerful, and governed.
Scoped API keys
Per-integration, hashed keys with explicit scopes and an org allowlist — least-privilege by default, individually revocable.
Signed webhooks
Every webhook is signed so you can verify it came from RegNexus and hasn't been tampered with.
Deterministic data model
Build against financial truth calculated from governed rules — stable, traceable, and safe to rely on.
Audit & provenance
API actions are audit-logged; results carry provenance you can verify with Frontier.
Surface
What you can build with.
Ledger & journals
Read financial state; propose journals for approval (never auto-posted).
Invoices, bills & contacts
Create and read commercial documents and counterparties.
Bank & reconciliation
Open Banking feeds (via TrueLayer) and reconciliation status.
VAT & filings
MTD VAT boxes and filing status.
Webhooks
Subscribe to events with signed delivery.
Endpoints and availability are disclosed per-account on onboarding. AI never posts to the ledger — the API proposes; humans approve.