SindhSales tax on services⚡ Sandbox + Production

SRB API Integration

Submit invoices to the Sindh Revenue Board through one canonical TaxBridge API. Sandbox, production, authentication, error handling and logs — without studying the SRB API directly.

Start SRB Sandbox View Documentation

SRB covers sales tax on services in Sindh.

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
  }'

SRB in one call

Integrate SRB Without the SRB-Specific Work

You send TaxBridge one canonical invoice. TaxBridge applies SRB’s field names, casing, money identity and success rules, then returns a single normalized result.

Authority	Sindh Revenue Board
Jurisdiction	Sindh
Covers	Sales tax on services
Header	`X-Tax-Authority: SRB`
Registration	e.srb.gos.pk

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: SRB" \
  -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
  }'

How SRB Integration Works

Four steps from account to your first approved SRB invoice.

1. Register & get approved

Create your TaxBridge company and verify your email. An admin approves the company for production access.

2. Subscribe & store SRB credentials

Pick a plan for SRB and fill the credential form. For SRB: pos_user and pos_pass — SRB authenticates with these inside the request body, not with a Bearer token.

3. Create an API key

Generate a test or live key, optionally pinned to SRB. The full key is shown once and stored only as a hash.

4. Post an invoice

Send your canonical invoice with X-Tax-Authority: SRB. Print the returned qrCode and keep the submissionId.

SRB authority quirk TaxBridge handles for you

One gateway serves both Test and Live. The environment is chosen by a flag (Test | Live), not by a different URL — so an API key’s environment, not the URL, is what keeps a sandbox test from filing a real invoice.

🔑

Credentials, encrypted

Your SRB credentials are AES-256-GCM encrypted at rest and never returned to your app.

🧪

Sandbox & simulator

Test SRB end-to-end before you hold production credentials.

⚠

Normalized errors

SRB rejections come back as a single status with a readable authorityMessage.

📋

Full request logs

Every SRB submission is logged with request, response and status for debugging.

🏢

Multi-branch

Run many outlets under one company — each branch’s SRB submissions are tracked separately.

🔄

Idempotent retries

A repeated Idempotency-Key replays the stored SRB result with no double submission.

SRB responses your code handles

HTTP	Meaning	What your code does
`201`	Approved by the authority	Print `qrCode`, store `submissionId`
`200`	Idempotent replay (`duplicate:true`)	Treat like the original — no quota consumed
`400 INVALID_INVOICE`	Normalizer rejected it; `details[]` lists every problem	Fix and resubmit — no quota consumed
`402 QUOTA_EXCEEDED`	Plan limit hit or subscription expired	Upgrade or renew
`409 DUPLICATE_INVOICE`	Invoice number already approved for this authority + environment	Do not resubmit
`422`	Authority rejected it (`status:"REJECTED"`)	Read `authorityMessage`, fix the data
`429`	Rate limit or sandbox soft cap	Honour `Retry-After`
`502 / 504`	Authority errored or timed out	Retry with the same `Idempotency-Key`

SRB API — FAQ

What is SRB API integration?

SRB API integration connects your software to the Sindh Revenue Board system for sales tax on services in Sindh, submitting invoices and returning a verifiable SRB result. TaxBridge maps your canonical invoice to SRB’s payload and authentication.

What software needs SRB integration?

Restaurants, hotels, salons, caterers, marriage halls and other Sindh service providers and the POS or ERP software they run, especially in Karachi and Hyderabad.

How does SRB authenticate?

SRB authenticates with a pos_user and pos_pass sent inside the request body, not with a Bearer token. You store these once in TaxBridge and they are encrypted at rest.

How are Test and Live kept apart?

SRB uses one gateway for both, selected by a flag. TaxBridge ties the flag to your API key’s environment, so a sandbox key can never file a real Live invoice.

Also integrating another province? See PRA · FBR · KPRA or the unified tax API.