IRN, EWB and credit/debit notes over one REST API.

GST E-Invoicing Software is a full UI for finance teams: dashboards, queues, GSTR-1 drafts, multi-GSTIN management. The E-Invoice API is the same underlying authorised-GSP integration, exposed as a REST API for engineering teams that want to embed IRN, EWB and CDNR generation directly into their own product, ERP or invoicing service. Same authorised-GSP path, no UI.

Yes. OneFinOps connects to the NIC IRP via authorised GSPs in the GSTN partner programme. Your traffic goes from your service to OneFinOps to the GSP layer to the NIC IRP. Multi-GSP routing kicks in when an IRP region is degraded, so your integration sees fewer downstream failures than a single-GSP setup.

The API queues the request locally and retries with exponential backoff against the failover GSP. Your client sees a single response (the eventual success or a clear failure with a GSTN error code). Webhook fires when the IRN finally lands. We publish IRP status on a public status page; the SDKs read from it to back off intelligently.

Sandbox uses GSTN-provided test PAN and GSTIN seed data. The schema, the validation rules and the response shape are identical to production. Rate limits and latency profiles are tuned to match production within tolerance, so you do not get a surprise on the day you cut over. To switch to production, you swap credentials, no code change required.

Default rate limits scale with plan: 10 requests per second on the developer plan, 100 on the standard plan, custom on the enterprise plan. Bulk endpoints accept up to 5,000 records per call. The X-RateLimit-* headers ship on every response so you can throttle from the client side.

Dual-key support is built in. Provision a new client credential, switch your traffic over, then revoke the old one. The audit log captures every issue, rotation and revoke event. Credentials never appear in webhook payloads or request logs; we redact them at the edge.

Each GSTIN gets its own OAuth client credentials. The auth scope is per-GSTIN, so a credential for GSTIN A cannot generate IRN against GSTIN B. SaaS platforms invoicing on behalf of their tenants can issue per-tenant credentials and let each tenant manage their own GSTN registration without exposing other tenants.

A monthly platform fee plus a per-IRN charge that decreases with volume. Bulk and reconciliation API calls are billed at lower rates than IRN-generating calls. The first 100 IRNs per month on sandbox are free for development. Detailed pricing is on the pricing page; volume tiers are negotiable on enterprise plans.

Send the Idempotency-Key header on any state-changing request (IRN, EWB, cancel, CDNR). The same key returns the same response within a 24-hour window. After 24 hours, the key is released. The replay window matches the GSTN's own duplicate-detection window, so you cannot accidentally generate two IRNs for the same invoice.

Yes. We share SOC 2 Type II report (gated NDA), the architecture diagram, the data-flow diagram and the GSP partnership documentation. Indian customer data is hosted in India. The API is exposed only over TLS 1.3, with HSTS, certificate pinning support in the SDKs, and request signing on every call.