The Engineer Who Wired the SaaS Stack Together
Before your HRIS syncs to your ATS, before your CRM talks to your ticketing system, before the data your customers need flows from one platform to another without a single line of one-off glue code - someone had to build the infrastructure that makes that possible. At Merge, that work landed in the hands of engineers like Nathan Stewart.
Stewart joined Merge in its early days, when the company was a small team in San Francisco working to solve one of software's most persistent headaches: the integration problem. Every B2B SaaS company eventually faces the same ask. Their customers want the product to connect to their HRIS, their ATS, their CRM, their payroll system. Building each integration from scratch is expensive, slow, and technically brutal to maintain. Merge's answer was a unified API - one integration to build, hundreds of third-party systems to unlock.
Stewart is a backend developer, which puts him exactly in the center of everything that makes that promise work. Unified APIs are deceptively hard. The data models across different HRIS vendors, for instance, share broad categories but diverge sharply in the details. Normalizing them at scale, handling auth flows, managing rate limits, detecting errors before customers do - that's the unglamorous engineering work that determines whether the product is useful or just interesting.
"Integrations were extremely expensive to build and maintain, but absolutely critical in order to grow." - The problem Merge was built to solve.- Merge Founding Story
From Ohio State to Production APIs
Stewart studied at The Ohio State University, where he built a foundation in systems-level thinking that shows up distinctly in his personal projects. His GitHub history - not a resume, an actual record of what he chooses to build when nobody is assigning the work - includes a Playfair cipher cracker using simulated annealing, parallel computing work on a supercomputer, and a network encryption project demonstrating encrypted packet transmission.
These aren't tutorial projects. Simulated annealing applied to cryptanalysis requires understanding optimization theory. Parallel computing on supercomputer architectures requires thinking about memory, concurrency, and scale. The pattern is a backend engineer who gravitates toward problems with both mathematical depth and systems complexity.
On his personal website, Nathan Stewart describes himself as a "Software Engineer & Puzzle Aficionado" - and he is active on Project Euler, the site that presents mathematical challenges designed specifically to require algorithmic thinking. It's a detail that says something about how he approaches problems. A puzzle aficionado doesn't look for the first answer. They look for the elegant one.
He goes by "Nate" informally. His handle across platforms is @n8stewart - a piece of programmer wordplay where the "8" represents "ate," turning the three characters into a readable name. It's a small thing. It also suggests someone who's been thinking in patterns and substitution codes since before they built a Playfair cipher cracker for fun.
Inside Merge
Merge was founded in 2020 by Shensi Ding and Gil Feig - two Columbia classmates who each ran into the integration wall at different companies and decided to solve it once rather than watch every startup in the ecosystem solve it separately. Their Series B in October 2022, a $55M round led by Accel with Addition and NEA participating, gave the company the runway to scale. Forbes named them a Cloud 100 Rising Star and included them in Next Billion-Dollar Startups 2023.
By the time Stewart had been there for a few years, Merge had expanded well beyond its original HRIS and ATS focus. The platform now covers CRM, accounting, ticketing, file storage, and payroll - and more recently, the company pivoted to meet the AI moment with two new products: Merge Agent Handler, which gives AI agents secure access to thousands of pre-built tools, and Merge Gateway, which handles LLM access with routing and governance controls. The problem Merge was built to solve didn't go away when AI arrived. If anything, it got more pressing.
Career Arc
The Specifics
Built a Playfair cipher cracker using simulated annealing as a personal project - applying optimization theory to cryptanalysis for fun.
His GitHub shows parallel computing work on supercomputers - an AMR (Adaptive Mesh Refinement) simulation in C, demonstrating high-performance systems thinking.
Active on Project Euler, solving mathematical programming challenges - a reliable signal of someone who finds algorithmic elegance as satisfying as shipping code.
The handle @n8stewart is classic programmer wordplay: "N" + "8" (eight = ate) + "Stewart" = Nate Stewart. Used consistently across GitHub, Twitter, LinkedIn, and Stack Overflow.
Active on Stack Overflow under the same n8stewart handle - contributing to the developer community while building production systems at a well-funded startup.
Merge is headquartered at 415 Mission St, San Francisco - a Salesforce Tower address that puts them in the center of the enterprise SaaS world they're integrating.
What He Builds With
The Merge stack - visible from job postings and technology data - includes React Redux, Vercel, Cloudflare infrastructure, Google Workspace, and a modern cloud deployment model. Stewart's backend role sits in the layer that makes the integrations actually work: auth flows, data normalization, rate limiting, error detection, and the webhook management that keeps data flowing in real time.