Every minute Kintsugi's sales tax API is unavailable, customers fail to collect roughly $4,000,000 in tax they're legally required to collect. That figure, from co-founder and CEO Pujun Bhatnagar, says a lot about how Kintsugi approaches infrastructure. It isn't treated as a background system that just needs to stay on. It's treated as part of the compliance product itself, which means every layer underneath it gets built with the same scrutiny as the tax logic on top.
Most sales tax platforms are judged on what they calculate. Our team has spent just as much time on what happens before and after that calculation: how fast the answer arrives, how the system behaves under unpredictable load, what AI is and isn't allowed to decide on its own, and how the whole thing is secured.
Speed That Matches Every Transaction
A shopper enters their address at checkout. The merchant's platform calls the Kintsugi tax engine in order to calculate and charge the correct tax rate. The answer needs to arrive before that shopper finishes paying, typically within 100 milliseconds. Miss that window, and the merchant doesn't collect sales tax on the transaction. They still owe it at the end of the month, out of their own margin.
The need for real-time, accurate tax calculations became the foundation of the infrastructure decisions we made while building Kintsugi. Originally, we ran our tax engine on AWS Lambda, but Lambda's tightly coupled memory and CPU limits meant scaling issues sometimes failed silently, showing up as cost overruns or slowdowns only after the fact, which wasn’t acceptable. We rebuilt around infrastructure that scales on actual latency and demand, deliberately avoiding lock-in to a single cloud provider so the system could grow on its own terms rather than a vendor's.
Some customers call the API as often as 3,000 times a second, and the infrastructure adapts to that in real time instead of forcing the business to plan around worst-case estimates. Since making that shift, Kintsugi's customer base has grown by 10x without infrastructure becoming a limiting factor.
Applying AI Where it Counts
Most AI tools in accounting and finance today are general-purpose, built to handle almost any task. They’re flexible, but that flexibility comes at a cost: general models are optimized to sound plausible across every subject, not to be precise about whether a specific product is taxable in a specific state this quarter. Sales tax isn't a reasoning problem. It's a rules problem, and the rules are specific, frequently updated, and dependent on jurisdiction, product category, and transaction type.
Read more: General AI Wasn’t Built for Sales Tax
We built Kintsugi to be distinct from tax engines that force AI into every part of the workflow. Here, AI handles the high-volume, rules-based work: nexus monitoring across jurisdictions, product classification, transaction reconciliation, exposure and risk scoring, and tracking regulatory changes across all 50 states and 100+ countries. But the tax calculations themselves stay deterministic, not probabilistic, and every critical output is reviewed by our tax experts before it counts. That's not a limitation of the technology. It's a deliberate design choice, because a system that's mostly right isn't a system you can build a compliance product on.
Verified Security
Sales tax compliance involves sensitive data for our customers: revenue broken out by state, customer billing details, exemption certificates, and a full picture of where and how a business operates. As AI features become standard across accounting software, the diligence around who can see that data, and how it's protected matters more than ever.
We’re SOC 2 Type II certified, which means our security is verified annually by an independent third party against the AICPA's Trust Services Criteria. We encrypt sensitive data both at rest and in transit and run access through modern authentication standards. Our platform is built on a secure, multi-zone AWS architecture with role-based, least-privilege access controls. None of this is reserved for enterprise tiers. It's the baseline for every customer, backed by a documented, tested incident response plan and a 99.9% uptime target.
We Built Kintsugi’s Foundation to Last
None of these pieces – the latency target, the infrastructure that scales on real demand, the deterministic AI approach, the independently verified security – exist in isolation. They all reflect a commitment that every member of the Kintsugi team has made: to build the parts of the product customers don't see with the same care as the parts they do.
Sales tax compliance is a practice in precision. There’s not much room for “mostly reliable” or “pretty accurate.” It’s not something that you can go back and improve upon after scaling. So we built Kintsugi with our highest standards in mind from day one.
If you’re interested in talking with our team about getting started with Kintsugi, reach out for a demo.
