Can I test before I have real tax-authority credentials?

Yes. Enable the simulator on a sandbox credential and TaxBridge answers submissions locally with no network call, so you can build your whole integration first.

How do I test error paths?

Use the magic invoice-number prefixes: TEST-REJECT returns a rejected result and TEST-TIMEOUT returns a failed/timeout result. Everything else is approved with a SIM invoice number.

🧪 Simulator⚡ Test keys⚡ No network call

Test Tax Integrations Safely Before Going Live

The TaxBridge sandbox lets you build and verify your entire integration — with a simulator that needs no real credentials, deterministic error tests, and full request logs.

Start Sandbox Testing Read the Docs

Sandbox never consumes production quota, and a sandbox key never works against production.

POST /api/v1/invoices

curl -X POST https://taxbridge.themetasum.com/api/v1/invoices \
  -H "Authorization: Bearer tbk_test_9f3a21c7b4d6e8f0_..." \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: 0b6d1c4e-7f9a-4a51-8d3c-2e5f7a91b204" \
  -H "X-Tax-Authority: PRA" \
  -d '{
    "invoiceNumber": "INV-10001",
    "invoiceDate": "2026-08-10T10:30:00",
    "invoiceType": "Sale",
    "currency": "PKR",
    "paymentMode": "Cash",
    "customer": { "name": "Walk-in Customer" },
    "items": [{
      "description": "Chicken Karahi Full", "hsCode": "11001010",
      "quantity": 1, "unitPrice": 1500.00,
      "taxRate": 16, "taxAmount": 240.00, "total": 1740.00
    }],
    "subTotal": 1500.00, "tax": 240.00, "total": 1740.00
  }'

🔑

Sandbox credentials

Generate a tbk_test_ key and store authority credentials — or skip them with the simulator.

🤖

Built-in simulator

Submissions are answered locally with realistic latency and a SIM-<AUTHORITY>-<hex> invoice number.

⚠

Deterministic error tests

TEST-REJECT... returns a rejection; TEST-TIMEOUT... returns a timeout. Test every path.

📋

Request logs

Inspect the exact request, response and normalized status for each test submission.

✅

Response validation

Confirm status, authorityInvoiceNumber, qrCode and quota before you touch production.

🔄

Idempotency testing

Replay an Idempotency-Key and confirm the stored response comes back with no quota consumed.

Two magic prefixes for error paths

While the simulator is on, invoice-number prefixes let you trigger exact outcomes deterministically — so you can build and prove your retry and rejection handling before real credentials exist.

TEST-REJECT... → rejected (authority error)
TEST-TIMEOUT... → failed / timeout
anything else → approved after 50–250 ms

POST /api/v1/invoices

curl -X POST https://taxbridge.themetasum.com/api/v1/invoices \
  -H "Authorization: Bearer tbk_test_9f3a21c7b4d6e8f0_..." \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: 0b6d1c4e-7f9a-4a51-8d3c-2e5f7a91b204" \
  -H "X-Tax-Authority: PRA" \
  -d '{
    "invoiceNumber": "TEST-REJECT-0001",
    "invoiceDate": "2026-08-10T10:30:00",
    "invoiceType": "Sale",
    "currency": "PKR",
    "paymentMode": "Cash",
    "customer": { "name": "Walk-in Customer" },
    "items": [{
      "description": "Chicken Karahi Full", "hsCode": "11001010",
      "quantity": 1, "unitPrice": 1500.00,
      "taxRate": 16, "taxAmount": 240.00, "total": 1740.00
    }],
    "subTotal": 1500.00, "tax": 240.00, "total": 1740.00
  }'

Create your sandbox

Build your integration with the simulator today; add real credentials when the authority issues them.

Start Sandbox Testing Getting Started

No developers? No API? No problem

Don’t want to build an integration at all?

Just register your business with Sum Cloud POS — it already files fiscal invoices to FBR, PRA, SRB and KPRA for you. No API, no development, nothing to connect or maintain. Start selling with compliant invoices out of the box.