E-Invoicing REST API
Send, validate, and track Peppol & ZATCA e-invoices programmatically. Sub-200ms AI validation, webhook callbacks, and a full OpenAPI 3.1 specification.
Standard
REST + JSON
< 200ms
Validation
OAuth 2.0
Auth
OpenAPI 3.1
Spec
Core Endpoints
/v1/invoices
Submit a new invoice for validation and delivery via Peppol or ZATCA.
/v1/invoices/{id}
Retrieve invoice status, validation results, and delivery confirmation.
/v1/invoices/validate
Validate an invoice without submitting. Returns Traffic Light Protocol result.
/v1/invoices/batch
Submit up to 500 invoices in a single batch for parallel processing.
/v1/invoices/{id}/pdf
Download the rendered PDF representation of a validated invoice.
/v1/compliance/countries
List all supported countries with current mandate status and format requirements.
Quick Start
// Submit an invoice for validation and Peppol delivery
const response = await fetch("https://api.invostaq.com/v1/invoices", {
method: "POST",
headers: {
"Authorization": "Bearer YOUR_API_KEY",
"Content-Type": "application/json",
"Idempotency-Key": "inv-2026-03-001"
},
body: JSON.stringify({
format: "ubl",
network: "peppol",
sender: { peppolId: "0208:BE0123456789", country: "BE" },
receiver: { peppolId: "0007:5567321122", country: "DE" },
invoice: "<base64-encoded UBL XML>"
})
});
const result = await response.json();
// {
// "id": "inv_abc123",
// "status": "delivered",
// "validation": {
// "trafficLight": "green",
// "syntaxErrors": 0,
// "semanticWarnings": 0,
// "processingTimeMs": 142
// }
// }API Capabilities
Sub-200ms Validation
Every API call runs through the Intelligent E-Invoicing Solution — Syntax AI Guardian and Semantic AI Audit — returning validation results in under 200 milliseconds.
Traffic Light Protocol
Each invoice gets a Pass (green), Warn (amber), or Block (red) status. Warnings include plain-English explanations and suggested corrections.
Webhook Callbacks
Register webhook URLs to receive real-time notifications when invoices are validated, delivered, acknowledged, or rejected by tax authorities.
OpenAPI 3.1 Specification
Full OpenAPI 3.1 spec for auto-generating client SDKs in any language. Supports UBL 2.1 and CII (Cross-Industry Invoice) input formats.
OAuth 2.0 + API Keys
Authenticate via OAuth 2.0 client credentials or API keys. TLS 1.3 encryption on all endpoints. SOC 2 Type II compliant infrastructure.
Multi-Standard Support
Single API endpoint handles Peppol BIS 3.0, ZATCA FATOORA Phase 2, EN 16931, XRechnung, FatturaPA, Factur-X, and more — route invoices to the correct network automatically.
Idempotent Requests
Every mutation endpoint supports idempotency keys. Safe retries on network failures without duplicate invoice submissions.
Analytics & Reporting
Programmatic access to compliance dashboards, validation statistics, error trends, and monthly volume reports via the reporting API.
99.9% Uptime SLA
Enterprise-grade Azure infrastructure with multi-region redundancy. Real-time status page and automated failover. Rate limits up to 1,000 requests/second on Enterprise plans.
InvoStaq's E-Invoicing REST API allows developers to integrate Peppol and ZATCA e-invoicing into any application, ERP system, or workflow. The API accepts UBL 2.1 and CII invoice formats and automatically routes them through the correct compliance network based on recipient country and tax authority requirements. Every invoice passes through InvoStaq's AI engine — combining Syntax AI Guardian (structural validation against EN 16931, BIS 3.0, ZATCA rules) and Semantic AI Audit (contextual tax logic checks powered by Azure AI) — in under 200 milliseconds. The API supports OAuth 2.0 authentication, webhook callbacks for real-time status updates, batch processing of up to 500 invoices per request, and idempotent operations for safe retries. Available on all plans starting at €49/month (Connect), with rate limits up to 1,000 requests/second on Enterprise plans.
Ready to Integrate?
Get your API key and start sending compliant invoices in minutes.