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Validate Canada Tax ID Numbers via API
When building B2B applications that serve Canada (Canada / Canada), validating your customers' GST/HST Registration Number is essential for B2B compliance and protecting your business from tax liability.
The TaxID API provides instant format validation and live lookup for Canada GST/HST Registration Number numbers via CRA (Canada Revenue Agency). Every request returns the validation status with sub-100ms response times for cached results.Canada applies a standard rate of 5% (GST/HST Registration Number).
QUICK START
curl -H "Authorization: Bearer YOUR_API_KEY" \ http://localhost:3000/api/v1/validate/CA/123456789RT0001
Code examples
Choose your language. Every example validates a Canada VAT number and returns the registration status with company details.
const res = await fetch('http://localhost:3000/api/v1/validate/CA/123456789RT0001', {
headers: { 'Authorization': 'Bearer YOUR_API_KEY' }
});
const data = await res.json();
// { valid: true, status: "active", company_name: "...", country_code: "CA", cached: false }
console.log(data);When to validate Canada tax ID numbers
B2B invoicing and accounts payable
When issuing or receiving invoices from Canada businesses, validating the GST/HST Registration Number ensures the identifier is genuine before committing the transaction to your ERP. Invalid or fabricated tax IDs are a leading vector for invoice fraud and can result in rejected filings or audit penalties.
SaaS and e-commerce checkout
If your platform serves Canada business customers, collecting and validating their GST/HST Registration Number at checkout is required for accurate tax treatment, correct invoicing, and downstream reporting. An invalid tax ID at the point of sale creates a correction burden across your finance stack.
Supplier and marketplace onboarding
For procurement platforms and regulated marketplaces onboarding Canada sellers or vendors, validating the GST/HST Registration Number at registration prevents fraudulent or duplicate accounts from entering your ecosystem. Validate once at onboarding, then re-validate periodically to detect deregistrations or changes.
About Canada VAT format (GST/HST Registration Number)
Canada's federal GST is 5%. Most provinces also levy a provincial sales tax (HST ranges from 13–15%). A GST/HST number is 15 characters: 9-digit BN (Business Number) + RT + 4-digit program account number. Quebec has its own QST system administered separately by Revenu Québec.
| Field | Value |
|---|---|
| Country code | CA |
| Local name | GST/HST Registration Number |
| Format | 9 digits + RT + 4 digits |
| Regex pattern | ^[0-9]{9}RT[0-9]{4}$ |
| Example | 123456789RT0001 |
| VIES supported | No |
VAT rates in Canada
Canada applies a standard GST/HST Registration Number rate of 5%.
| Rate type | Percentage | Currency |
|---|---|---|
| Standard rate | 5% | CAD |
Frequently asked questions
What is the Canada tax ID number format?
Canada tax ID numbers (GST/HST Registration Number) follow the format: 9 digits + RT + 4 digits. A valid example is 123456789RT0001. The TaxID API validates the format locally and where possible checks against the CRA (Canada Revenue Agency), ensuring you only accept properly registered businesses.
Should I validate GST/HST Registration Number numbers when transacting with Canada businesses?
Validating GST/HST Registration Number numbers reduces fraud risk, prevents invalid identifiers from entering your accounting system, and is required by many B2B contracts and procurement platforms. While mandatory rules vary by jurisdiction, validating at onboarding is widely considered best practice — especially for SaaS, marketplace, and fintech platforms with global customer bases.
What is the standard tax rate in Canada?
The standard tax rate in Canada is 5% (GST/HST Registration Number). Canada applies a single flat rate with no reduced rates. The TaxID API's /rates endpoint returns all current rates for programmatic access.
How long does Canada tax ID validation take with TaxID?
For cached results (previously validated in the last 24 hours), the TaxID API responds in under 10ms. Format validation is instantaneous. For uncached requests requiring a live lookup against CRA (Canada Revenue Agency), response time is typically 100–500ms. Valid numbers are cached for 24 hours; invalid numbers are cached for 1 hour.
How does the TaxID API validate Canada GST/HST Registration Number numbers?
The TaxID API validates Canada GST/HST Registration Number numbers in two steps: first it checks the format against the official pattern (9 digits + RT + 4 digits), then it queries CRA (Canada Revenue Agency) where a live API is available. Canada's federal GST is 5%. Most provinces also levy a provincial sales tax (HST ranges from 13–15%). A GST/HST number is 15 characters: 9-digit BN (Business Number) + RT + 4-digit program account number. Quebec has its own QST system administered separately by Revenu Québec.
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