11Sigma at Stoplight

Building API design tools together since 2018


Austin, USA


API Tooling

Total funding amount

$21M (Feb, 2021)

About Stoplight

Stoplight is a USA startup from Austin, Texas innovating in the API tooling space. They build tools for designing, documenting, and governing APIs following the Design-First principles.

To quote their website, they provide tools that help “Design, Document & Build Quality APIs Faster”.

The company was founded in 2015 by Marc MacLeod and accelerated in Austin Techstars Accelerator.

Total funding to date is around $21M, with the latest being a $11M round of follow-on Series A in February 2021.

They currently serve over 600 companies including such brands as Amadeus, EA, Deutsche Bank.

Check out Stoplight tools


In October 2018, Stoplight received $3M seed funding. Their team was still very small and, besides one salesperson, head of growth, and a couple of other essential employees consisted of just several core engineers. Marc MacLeod (the founder and CEO) was still actively involved in engineering.

Up to that point, Stoplight shipped two versions of their product and was preparing for another rapid redesign and fast growth.

The immediate need was straightforward. Stoplight needed trusted TypeScript engineers to rewrite one of their core components responsible for mocking and proxying HTTP requests (an OpenSource project, called Prism). The initial success with Prism led to supporting Stoplight in solving more challenges: hiring, managing remote teams, building flagship products, continuous delivery, and more.

Stoplight is our first client

  • Hire motivated, startup-minded TypeScript experts remotely

  • Competing with FAANG for engineers on local market in Austin

  • Support engineers' professional self-growth & retain best engineers

  • Build flagship product, pivot fast, find product-market fit

  • Establish a lightweight hiring process

  • Keep the remote team in Europe motivated, energized and happy

  • Need for end-to-end test automation & a bespoke QA process

  • Lack of engineers with Team Leader experience

Together since
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Since we joined in 2018, Stoplight continued to work on its major products allowing its customers to design, document, explore, and govern APIs. 

Besides TypeScript engineering work, we’ve started organizing team building events in Europe before the year 2018 ended. We hosted the first micro-retreat in Warsaw, Poland, where the 11Sigma crew, Stoplight’s director of engineering (flew to Poland from the USA), and some in-house engineers had a chance to meet, work and have fun together. Following up on this event’s success, we’ve soon organized another one in Sopot, Poland – a seaside resort where we rented a hacker-apartment in a XIX century villa. That started a tradition of annual retreats (like the one in Głęboczek)on-site on-boardings in Poznań, and regular trips to conferences (API Days Barcelona, API Days Paris).

In early 2019, we became responsible for managing the entire European team (Stoplight + 11Sigma) and hired two more engineers to Stoplight. Late 2019 was the advent of setting up a QA process. We continued working on Studio, Spectral, Prism, and redesigned workspace-based Platform. By the end of 2019, we hired one more engineer (a senior who soon became a team leader) and onboarded and mentored a manual QA that became an SDET and later a junior developer in under a year.

In 2020, we continued extending Stoplight’s team with more senior engineerscreated and coordinated a QA process across the boardautomated e2e tests (which enabled Continuous Deployment). Our engineers had a significant impact on developing all products and continue to remain the top contributors.

For all those years, we’ve been building and improving a dedicated hiring process. When Stoplight had very few resources to develop their own, we’ve taken the lead and prepared the hiring processes, including the messaging, tasks, questions, and job marketing strategy. We’ve also set up the infrastructure, screened CVs, reviewed candidates’ home-assignments, conducted live-coding interviews, and prepared detailed 360-degree candidate profiles. To give an example for one of the jobs, we’ve reviewed over 300 candidates in under a month and selected 5 for a final interview with the USA team.

In the meantime, we’ve been supporting our engineers in their personal growth. Our goal-oriented 10x-self sessions with individual engineers resulted in many success stories. Some of them are technical, like starting a technical blog, creating a YouTube channel about JavaScript, or being promoted to more senior positions. Some are very personal, like getting back to their own passions such as flying or contributing to OpenSource projects.

It’s been a unique partnership since Karol and I met Stoplight’s founder, Marc MacLeod. This uniqueness is based on the fact that we’ve always been treated like first-class citizens and “part of the team”.

Except for the paperwork, there is practically no difference between 11Sigma engineers and in-house employees.

We’ve been able to achieve this kind of relationship because of the unique characteristics of our model:

  • We focused on building a dedicated “11Sigma at Stoplight” crew
  • We built and conducted a bespoke hiring process
  • We adapt to Stoplight’s organizational changes (seed -> post-Series A)
  • Our engineers work full-time at Stoplight (we don’t split our engineers’ time between clients)
  • We inherit Stoplight’s culture, as well as organize and engage in various team-building events
  • Providing team extension service and growing the engineering team (100% remote, across entire Europe)

  • Taking care of reaching to TypeScript experts in Europe

  • Mentoring and supporting 11Sigma engineers's growth

  • Major engineering contributions to all flagship products such as Studio and Platform

  • Creating a bespoke hiring process and transparently shared hiring resources

  • Organizing team-building, on-site events & lead conference trips around Europe

  • Created a QA process from scratch and wrote the entire e2e test base

  • Leading Stoplight teams & managing juniors to a successful growth

Selected contributions


Studio, Stoplight's flagship product, is a tool for API design, modeling, and writing API documentation. Our engineers have been contributing to this project since its beginning - practically each part of the software. Achieving a real-time collaboration and editing of large APIs required applying advanced web development techniques, cutting-edge browser APIs, and expert React and TypeScript knowledge.


Spectral is "a flexible JSON/YAML linter, with out of the box support for OpenAPI v2/v3 and AsyncAPI v2." We've helped develop some of the core functionalities. Our engineers are one of the most active contributors to the project.


Prism is another great Stoplight's OpenSource tool for creating mock servers with OpenAPI files. Our engineers contributed to most of its functionality.


Makes managing APIs at-scale very easy. It features governance, documentation, mocking, collaboration. Integrates with git providers and provides discoverability tools that help searching your APIs. We've helped building the backend services as well as the UI components.

Stoplight's executives about 11Sigma

"11Sigma extended our team with very productive and highly motivated engineers. They are smart people who get the job done, whatever you throw at them. It has been a pleasure working with them!"
Marc MacLeod
Founder, CPO, former CEO
"It’s a pleasure working with 11Sigma! They are a team of high producing engineers who communicate well. They continuously look for ways to optimize processes and best integrate into new or existing workflows."
Scott Faust
Head of Growth
"11Sigma has a very good interview process. They involved the right people at Stoplight and coordinated it to get things done.​"
Harrison Yeager
Head of Operations

Current 11Sigma crew at Stoplight

Jakub Jankowski

Software Engineer

Domagoj Kriskovic

Software Engineer

Łukasz Kużyński

Senior Software Engineer

Michał Miąskowski

Software Engineer

Sergey Radzishevskii

Software Engineer

Fully distributed, remote-first team