11 FAQs related to GST Verification in Canada

My cousin mentioned GST verification when she was talking about her bakery last month. Had no idea what she meant, so naturally, I went down a bit of a rabbit hole reading about it.

Turns out it's actually pretty interesting how the whole system works. Found myself bookmarking a bunch of different pages and forums where people were asking similar questions.

Figured I might as well put together what I learned since I already did all the digging anyway. These are the main questions I kept seeing pop up everywhere, plus what I managed to figure out about each one.

How do I verify a GST/HST number in Canada?

The CRA gives you a few ways to do this, and honestly, which one you pick depends on how many suppliers you're dealing with.

• CRA's online tool: Head to the GST/HST Registry and punch in the supplier's 9-digit number, their registered business name, and your transaction date. It'll spit out whether they're actually registered for that specific date.
• Pick up the phone: Can't find the number or getting weird results online? Call 1-800-959-5525 and let the CRA folks do the legwork for you.
• Go automated: If you're checking suppliers constantly, API services can verify hundreds of numbers in one shot. Instead of spending your afternoon clicking through the CRA website, upload a spreadsheet and get all your verifications done in minutes.

Save whatever confirmation you get - screenshot, printout, whatever. The CRA will want to see proof that you actually checked when they come knocking about your ITCs.

What information do I need to verify a supplier's GST number?

Pretty straightforward - you need three things:

1. GST number
2. CRA registered name
3. Invoice date

Here's the thing that trips people up: if "Joe's Plumbing" is what's on their truck but they registered as "Joseph Smith Plumbing Services Inc.," you need to use the full legal name, or the search won't work.

Is GST verification free in Canada?

Yep, the government tools don't cost you a dime. The CRA's online registry and phone line are completely free. Some private companies charge for bulk verification services or automation APIs, but the basic verification through official channels costs nothing.

What's the difference between regular GST/HST verification and simplified GST/HST verification?

Most of the time, you'll use regular verification, but there's a separate system for digital businesses:

If you're buying from Netflix or downloading apps, you might need the simplified registry. For your local contractor or office supplies company, stick with regular verification.

What happens if I can't find a supplier's GST/HST number?

Start by asking your supplier directly - they're supposed to put their GST number on any invoice over $100. If they're dodging the question or claiming they don't need to register, that's a red flag. Call the CRA at 1-800-959-5525 and ask them to confirm whether this supplier should be registered. Better to spend five minutes on a phone call than lose thousands in denied tax credits later.

Can I claim input tax credits if a supplier's GST number is invalid?

Absolutely not, and this is where businesses get hammered. The tax courts don't care if you paid GST in good faith - wrong number means no credit, period. Even if your supplier gave you someone else's valid GST number by mistake, you're still out of luck. The courts have denied ITC claims worth hundreds of thousands because businesses didn't verify properly.

How often should I verify my suppliers' GST numbers?

No magic formula here, but think of it like checking references. New suppliers get verified before the first transaction, for ongoing relationships, maybe annually or when you renew contracts. High-dollar transactions or sketchy suppliers? Check every time. The CRA's database updates in real-time, so a supplier's status can change without warning.

What should I do if the GST Registry shows different information from my supplier's invoice?

Don't panic, but don't ignore it either. Call your supplier first - maybe they operate under a different name than what's registered. If the numbers don't match or show invalid, stop claiming ITCs on their invoices until it's sorted out. Document everything and call the CRA if your supplier can't explain the discrepancy. This stuff matters when audit time rolls around.

Are there penalties for not verifying GST numbers properly?

There's no "failure to verify" penalty, but the consequences hurt just as much. Courts routinely deny massive ITC claims when businesses can't prove they did basic due diligence.

Can I verify Québec Sales Tax (QST) numbers the same way?

Nope - Québec runs its own show. You need to use Revenu Québec's tools, not the CRA's GST registry. Here's how it works:

• Revenu Québec website: Their QST validation tool works like the CRA's, but only for Québec numbers
• Business-to-business API: Québec offers bulk verification for companies processing lots of suppliers
• Special cases: Some financial institutions get verified through the CRA at 1-800-959-5525 because of how the systems overlap

Digital businesses selling to Québec might have "NR" registration numbers - same verification process, different system. Don't mix up the two, or you'll get nowhere.

How can I automate GST verification for multiple suppliers?

If you're manually checking GST numbers one by one through the CRA website, you're doing it the hard way. Automation works by connecting directly to the same government databases the CRA uses, but instead of typing in supplier details individually, you can process hundreds or thousands at once.

The basic concept is simple: automated systems take your supplier list, send verification requests to the CRA's database, and return results for your entire list simultaneously. This happens through Application Programming Interfaces (APIs) that act as a bridge between your business systems and the government's verification database.

At Signzy, we've built our Canada GST verification API specifically to solve this problem. Our solution plugs seamlessly into your existing business processes, handling all the technical complexity while delivering clean, verified supplier data. When you're processing dozens or hundreds of suppliers regularly, our automation transforms verification from a tedious administrative task into a seamless background process that actually strengthens your compliance position. Book a demo here to know more.