Bo Jiang

A developer broke into his API. So he turned it into the product.

Somewhere around 2019, an engineer reverse-engineered the Privacy.com app to get at the card-issuing API humming underneath it. Most founders would have patched the hole. Bo Jiang read it as a memo from the market.

That instinct - to follow the thing people are quietly stealing rather than the thing you planned to sell - is the whole story of Lithic. Today Jiang is co-founder and CEO of a New York company that lets other businesses spin up card programs with a few API calls: set a limit, mint a card number, change the controls in real time. The pitch is unglamorous on purpose. Cards, he likes to point out, already work flawlessly at planetary scale. The interesting part is making them programmable.

Lithic sits on the boring, load-bearing layer of fintech - issuer processing, PCI compliance, reconciliation, the unglamorous machinery that moves money from one account to a vendor's. Jiang's bet is that most companies do not want to care how the money gets there. They just want it to arrive. "Your job-to-be-done is to pay your SaaS vendor," he has said. "You don't ultimately care how that money gets from your account to the vendor's account." Lithic's job is to make the caring optional.

Three teenagers, fifty rejections, one good idea

Jiang did not arrive in fintech the usual way. He grew up in the Midwest, went to Shawnee Mission South High School in Kansas, and met his two future co-founders - Jason Kruse and David Nichols - as a teenager, around the age of 13. They built websites together. They built an early Box competitor and sold it before college. Friendship came first; the cap table came much later.

He studied applied mathematics at MIT and spent a stretch as a research assistant at the MIT Media Lab. From there came a software job at Hatch Labs - the same incubator that spat out Tinder - and a stint at PixieTV, which Samsung later acquired. The pattern was set early: build the thing, ship the thing, move on.

In 2012 the trio tried something stranger - a Bitcoin-backed debit card. They pitched it to roughly fifty banks. Every single one said no. Most people would file that under failure. Jiang and his friends filed it under research. Two years later, the privacy-and-payments thread they had been pulling on became Privacy.com: single-use virtual cards that masked your real card details from merchants, letting you cancel a subscription by killing a card instead of fighting a customer-service queue.

When the back end is better than the front

Privacy.com had a problem most startups would envy: people loved it without being asked. Growth ran 70 to 80 percent organic. But to deliver the card experience they wanted, the team ran into a wall. Their original processor took more than a year and half a million dollars just to onboard, and the legacy stack underneath was two decades old. So they did the expensive, unfashionable thing. They spent two years rebuilding the issuer-processor infrastructure themselves, piece by piece.

That homemade plumbing turned out to be the asset. Developers wanted in. After the reverse-engineering incident and a flood of organic interest, the team launched a beta API in 2019, raised a $10.2M Series A in 2020, and in 2021 made the call that defines the company: they rebranded the infrastructure business as Lithic, raised a $43M Series B and a $60M Series C at a reported ~$800M valuation, and kept Privacy.com running as a consumer brand on top of the platform it had inspired. The app now rides the rails it built.

Jiang runs both, and is unsentimental about how. "It's really about finding leverage and hiring well for both businesses," he has said, describing his own role as being "really helpful and hands-on in hiring." He thinks about customer concentration the way a fund thinks about portfolio risk: no single customer above 15 percent of revenue, on purpose, so the roadmap answers to the long term instead of to whoever shouts loudest.

Stay in the lane. Build the enduring thing.

For all the developer-tools energy, Jiang's worldview is shaped by a market he calls deeply partnership-oriented. Sponsor banks, card networks, processing platforms - in card issuing, none of it runs on code alone. Coming from a pure engineering background, he has said, it is easy to under-appreciate how much of the work is relationships. Lithic's discipline is to do a few things very well and integrate cleanly with everyone else. "We're going to stay in our lane," he puts it. "We're going to work really well with other people. But we're going to be somewhat disciplined about the problems we solve."

He is allergic to the race to the bottom. Competing purely on price, in his telling, is a short-term sugar high that leaves you with a flimsier product. "We need to build an enduring business," he says. "Going with the absolute value player may feel good in the short term, but in the long term, it means you build a less robust offering." It is not the loudest pitch in fintech. It might be the most durable.

By 2023 the mix had tilted from consumers toward commercial use cases, tens of millions of cards had been issued, and the customer list had crossed a hundred companies. In 2024 Lithic expanded into Canada to smooth currency conversion, and marked ten years in business with the three childhood friends - now CEO, CTO and chief design officer - sitting down together to tell the story. The basement startup grew up. The friendship, apparently, survived the cap table.

The unglamorous case for being unglamorous

There is a tidy way to understand where Lithic fits. The legacy issuer-processors - the i2c's and Galileos of the world - run a model that, in Jiang's framing, is "fundamentally the same business model, but better technology." Marqeta, the publicly traded giant in the category, built much of its early business on a small number of enormous customers. Jiang watched that and drew the opposite lesson. He points instead to Stripe, Adyen and Plaid: companies that won by lowering the barrier to entry rather than chasing only the largest logos. Self-serve, in his telling, is not a feature. It is the entire commitment. "At the end of the day, it comes down to being committed to self-serve as a business and to expanding that."

That commitment shapes the product in concrete ways. Lithic's pieces are meant to be modular - card issuing, money movement, the rest - so a customer can bring their own ACH provider or plug Lithic's cards into infrastructure they already run. The company does not try to sell standalone ACH; it treats it as an add-on to the cards that are its center of gravity. The smart spend controls that sit on top let teams move quickly without asking permission for every transaction ahead of time. It is, in a sense, the Privacy.com idea grown up: give people fine-grained control over money, then get out of the way.

Jiang is also clear-eyed about what he is not rushing toward. International expansion interests him, but he has been candid that the right move is to wait for the right design partners rather than plant flags for the sake of a map. In a tighter funding environment, he has noted, most companies pull back toward their core, which pushes those timelines further out - and he is comfortable with that patience. The discipline he preaches about problem selection is the same discipline he applies to ambition.

What a math major learned about handshakes

For someone who came up through applied mathematics and a research lab, Jiang's hardest-won lesson is almost anti-technical. Card issuing, he has said, is a business of partnerships - sponsor banks, the card networks, processing platforms - and people from a pure software background tend to under-appreciate just how much of the work lives in those relationships rather than in the codebase. You can write the cleanest API in the world and still be stuck if the banking and network partnerships underneath it are not solid. Building infrastructure from scratch and integrating directly with the major card networks, he argues, is precisely what made later scaling challenges manageable; the company owned the parts that mattered instead of renting them.

Resource allocation, he admits, is one of the toughest parts of the job - deciding where a finite team should push when every customer wants something different. His answer is leverage. Lithic's promise to its best customers is that the platform gives them more capability than they could build themselves, by a margin wide enough to outweigh whatever they might save by bringing it in-house. It is a confident claim, and a measurable one, which is probably why he likes it.

Six lines that explain the bet