- For B2B digital services, place of supply is usually the customer's country, with the customer accounting for VAT under reverse charge
- For B2C digital services in the EU, the supplier must register and collect VAT through the OSS or IOSS schemes
- The US sales tax system operates on economic nexus thresholds that vary by state, with no national VAT equivalent
- The UAE, Singapore, and Australia each operate GST regimes for inbound digital services with their own registration thresholds and rules
Selling software to someone in Berlin is easy. Knowing whether you owe 19% VAT to Germany, 5% GST to their subsidiary in Dubai, or nothing at all because the buyer handed you a valid VAT ID: that part is where SaaS founders lose sleep. The place of supply question sits at the core of every cross-border tax obligation you will ever face, yet most founders only discover it after a tax authority sends a letter. Your pricing page, your Stripe settings, your invoicing templates, and even your terms of service all hinge on getting this right. If you sell digital services internationally, understanding VAT and GST across borders is not optional. It is the difference between a clean cap table and a six-figure retroactive tax bill that surfaces during due diligence. This guide walks through the place of supply rules that matter most to SaaS businesses, region by region, with the practical detail that generic overviews tend to skip.
Why place of supply is the most important rule you have never read
Place of supply rules determine which country has the right to tax a transaction. For a SaaS company selling subscriptions globally, this single concept dictates where you register, what rate you charge, and whether you collect tax at all. Get it wrong and you are either overcharging customers (killing conversion) or silently accumulating liabilities in jurisdictions you have never visited.
Most tax codes treat SaaS as an "electronically supplied service" or "digital service." The default rule in the EU, UK, UAE, Australia, and Singapore is that the place of supply for digital services sold to consumers is where the customer belongs, not where your company is incorporated. That means a SaaS startup based in Lisbon selling to a consumer in France owes French VAT at 20%, not Portuguese VAT at 23%.
The tricky part is that "where the customer belongs" varies by country. Some jurisdictions use the billing address. Others look at IP geolocation, the bank issuing the payment card, or the country code of the SIM card. You need two non-contradictory pieces of evidence in the EU, for example, which is more than most checkout flows collect by default.
B2B versus B2C: the rule that changes everything
The single biggest fork in the road for SaaS VAT is whether your buyer is a business or a consumer. In B2B sales, most jurisdictions shift the tax obligation to the buyer through a mechanism called the reverse charge. You, the seller, invoice without VAT. The buyer self-assesses the tax on their local return. Your registration obligation in that country often disappears entirely.
In B2C sales, the obligation stays with you. You must register in the customer's country (or use a simplification scheme like the EU's One Stop Shop), charge the local rate, file returns, and remit the tax. For a SaaS product with thousands of individual subscribers scattered across 30 countries, this is a logistical headache that compounds fast.
The practical takeaway: always collect and validate VAT identification numbers at checkout. A valid VAT ID is your evidence that the transaction is B2B. Without it, you default to B2C treatment, which means you owe the tax. Tools like VIES (the EU's VAT validation database) let you verify numbers in real time. If your checkout does not do this today, fix it this week.
The EU one-stop shop (OSS and IOSS) in practice
The EU's One Stop Shop exists specifically so you do not have to register in every member state where you have B2C customers. Under the non-Union OSS scheme (for businesses established outside the EU) or the Union OSS scheme (for EU-based businesses), you register in one EU country and file a single quarterly return covering all your EU B2C digital service sales.
Here is what catches founders off guard. OSS only covers B2C supplies. If you have B2B customers and mistakenly route those through OSS without applying the reverse charge, you create a mess: double taxation for the buyer and incorrect filings for you. IOSS, the Import One Stop Shop, applies to goods valued under EUR 150, not to SaaS. Confusing OSS and IOSS is surprisingly common in founder forums.
The rates you charge through OSS must match each customer's country. A subscription sold to a consumer in Ireland carries 23% VAT; the same subscription sold to someone in Luxembourg carries 17%. Your billing system needs a rate table that updates when member states change rates, which happens more often than you would expect. Poland raised its standard rate temporarily, and Estonia increased its rate to 22% in 2024.
The UK after Brexit: the new place of supply landscape
Since January 2021, the UK operates its own VAT regime entirely separate from the EU. If you sell digital services to UK consumers, you must register for UK VAT once you make any B2C digital sales there: there is no threshold. The rate is 20%.
For B2B sales to UK businesses, the reverse charge applies just as it did under EU rules. You need a valid UK VAT number from your buyer. Note that UK VAT numbers are formatted differently from EU ones (GB prefix, nine digits), and VIES does not validate them. HMRC provides its own lookup tool.
One detail that trips up EU-based SaaS founders: you cannot include UK sales in your EU OSS return. The UK is a completely separate registration. If you were using OSS to cover the UK before Brexit and never updated your setup, you have been filing incorrectly for over three years. HMRC has been increasingly active in identifying non-compliant overseas digital service providers, and penalties accrue from the date the obligation arose, not the date you discovered it.
The US sales tax problem (and why VAT founders underestimate it)
US sales tax for SaaS is a different beast entirely. There is no federal sales tax. Instead, you face a patchwork of state-level rules, each with its own definition of whether SaaS is taxable, its own economic nexus thresholds, and its own filing calendar.
After the 2018 South Dakota v. Wayfair decision, states can require remote sellers to collect sales tax once they exceed an economic nexus threshold: typically $100,000 in sales or 200 transactions in that state. About 25 states currently tax SaaS, though definitions vary. Texas taxes "data processing services." New York taxes SaaS sold to in-state customers. California does not tax SaaS at all (for now). Washington taxes it under its B&O tax framework, which is not even a sales tax.
The registration burden is real. Each state requires a separate filing, often monthly or quarterly. Many SaaS founders based outside the US ignore this entirely, assuming US sales tax only applies to US companies. It does not. If you exceed nexus thresholds in a state that taxes SaaS, you owe the tax regardless of where your company is incorporated. Services like Avalara or Anrok can automate multi-state compliance, but they cost money, and you still need to register in each state individually.
The UAE, Singapore, and Australia: GST regimes for digital services
The UAE charges 5% VAT on digital services supplied to UAE consumers by overseas providers. If your annual taxable supplies to UAE customers exceed AED 375,000 (roughly $102,000), you must register with the Federal Tax Authority. The FTA has been expanding its enforcement reach, and data inconsistencies between your reported revenue and payment processor records are a known audit trigger.
Singapore's GST regime requires overseas vendors to register if they make more than SGD 100,000 in annual B2C digital supplies to Singapore customers, or expect to exceed that threshold in the next 12 months. The rate rose to 9% in January 2024. Registration is done through the Overseas Vendor Registration regime, and you file quarterly.
Australia's GST applies at 10% to digital supplies made to Australian consumers. The threshold is AUD 75,000 in annual turnover. The Australian Taxation Office has been enforcing this since 2017 and has a simplified registration process for overseas vendors. One thing to watch: Australia requires you to account for GST on B2C sales but allows the reverse charge for B2B sales, similar to the EU model. Validating Australian Business Numbers (ABNs) at checkout is your mechanism for distinguishing the two.
Reverse charge, zero-rating, and the documentation you must keep
The reverse charge is your best friend in B2B cross-border sales, but it only protects you if your documentation holds up. At minimum, you need the customer's valid tax identification number, an invoice that states the reverse charge applies, and evidence that the supply is genuinely B2B. Generic templates pulled from the internet will not survive scrutiny from HMRC, the FTA, or any serious tax authority. Your intercompany and customer-facing invoices should be reviewed by someone who understands the specific requirements of each jurisdiction.
Zero-rating is different from the reverse charge. A zero-rated supply is still taxable, just at 0%. You report it on your return, and you can reclaim input VAT associated with it. An out-of-scope supply (like a reverse-charged B2B export) may not appear on your return at all, depending on the jurisdiction. Confusing these categories leads to incorrect filings and, eventually, assessments.
Keep records for at least six years: invoices, evidence of customer location (IP logs, billing addresses, payment card country), VAT ID validation results, and correspondence. If you are audited three years from now, the timestamp on that VIES check matters.
A pricing-page audit for global SaaS
Your pricing page is where tax compliance becomes visible to customers, and where mistakes become expensive. Here is a quick audit checklist:
- Does your checkout collect and validate tax IDs for B2B buyers before calculating the price?
- Are you displaying tax-inclusive or tax-exclusive prices, and is that consistent with local consumer protection rules? (The EU generally requires tax-inclusive pricing for B2C.)
- Does your billing system apply the correct VAT or GST rate based on the customer's country, not your company's country?
- Are you collecting two pieces of non-contradictory location evidence for EU B2C sales?
- Do your invoices include all mandatory fields for each jurisdiction: your VAT number, the customer's VAT number (if B2B), the applicable rate, and the correct reverse charge language?
- Have you registered in every jurisdiction where you have crossed the threshold?
If you answered "no" or "I'm not sure" to any of these, you have compliance gaps that grow with every new subscriber.
The founders who handle this well treat tax compliance as a product feature, not an afterthought. They build location detection into their checkout, automate rate lookups, validate tax IDs in real time, and review their obligations quarterly as revenue grows into new markets. The founders who do not end up retrofitting compliance under pressure, usually right before a funding round when investors or their lawyers start asking uncomfortable questions. Fix it now, while the cost is measured in engineering hours rather than back taxes and penalties.
