Top Series B Developer tools companies

IDEs, runtimes, frameworks, and platforms built primarily for engineers. Filtered to companies whose latest disclosed round is Series B.

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Ranked by current headcount across Series B Developer tools companies. Refreshed monthly.

1
Instagram
More than one billion people around the world use Instagram, and we’re proud to be bringing them closer to the people and things they love. Instagram inspires people to see the world differently, discover new interests, and express themselves.Since launching in 2010, our community has grown at a rapid pace. Our teams are growing fast, too, and we’re looking for talent across engineering, product management, design, research, analytics, technical program management, operations, and more. In addition to our headquarters in Menlo Park, we have thriving offices in New York City and San Francisco where teams are doing impactful work every day.
- Series B
- 61k employees
- Founded 2010
2
Alibaba.com· Hangzhou, Zhejiang, China
The first business of Alibaba Group, Alibaba.com (www.alibaba.com) is the leading platform for global wholesale trade serving millions of buyers and suppliers around the world. Through Alibaba.com, small businesses can sell their products to companies in other countries. Sellers on Alibaba.com are typically manufacturers and distributors based in China and other manufacturing countries such as India, Pakistan, the United States and Thailand.Our MissionAs part of the Alibaba Group, our mission is to make it easy to do business anywhere. We do this by giving suppliers the tools necessary to reach a global audience for their products, and by helping buyers find products and suppliers quickly and efficiently.One-Stop SourcingAlibaba.com brings you hundreds of millions of products in over 40 different major categories, including consumer electronics, machinery and apparel.Buyers for these products are located in 190+ countries and regions, and exchange hundreds of thousands of messages with suppliers on the platform each day.Anytime, AnywhereAs a platform, we continue to develop services to help businesses do more and discover new opportunities. Whether it’s sourcing from your mobile phone or contacting suppliers in their local language, turn to Alibaba.com for all your global business needs.
- Series B
- 29.3k employees
- Founded 1999
3
Railway· San Francisco, California, United States
Railway’s mission is to build the cloud computing stack that unburdens you, so you can focus more on what matters to you.
- Series B
- 11.4k employees
- Founded 2020
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4
Grammarly· San Francisco, California, United States
Grammarly stands with Ukraine. We invite you to do the same. Here are some ways you can help: gram.ly/WeStandWithUkraine ---Grammarly is the world’s leading AI writing assistance company trusted by over 40 million people and 50,000 organizations every day. From instantly creating a first draft to perfecting every message, Grammarly helps people at 96% of the Fortune 500 get their point across—and get results—without compromising security or privacy. We believe that great writing gets work done. Grammarly’s product offerings—Grammarly Business, Grammarly Premium, Grammarly Free, and Grammarly for Education—work where you do, delivering contextually relevant writing support across over 500,000 apps and websites. Founded in 2009, Grammarly is No. 7 on the Forbes Cloud 100, one of TIME’s 100 Most Influential Companies, one of Fast Company’s Most Innovative Companies in AI, and one of Inc.’s Best Workplaces. Grammarly offers a dynamic hybrid working model. This approach helps foster trust, innovation, and a strong team culture, with the flexibility of working from home, whenever you need focus time.
- Series B
- 9.8k employees
- Founded 2009
5
micro1· San Francisco Bay Area, California, United States
the leading data lab that builds real-world RL environments to train models and agents
- Series B
- 9.5k employees
- Founded 2022

6
Calendly· Atlanta, Georgia, United States
Calendly connects the entire meeting workflow — scheduling, payments, meeting notes, follow-ups, contacts, and more — and handles the work before, during, and after meetings. From solo business owners to teams within large organizations, more than 50 million people across 240+ countries trust Calendly to help them get more out of every meeting.If you're thinking about joining us, we want the people who build Calendly to experience the same value our customers do. You'll own tangible work, see it reach real customers, and grow through the challenges that come with building something meaningful. We're remote-first, guided by strong values, working alongside people who care about the work and each other.
- Series B
- 9.4k employees
- Founded 2013
7
Outlier AI· Oakland, California, United States
Outlier shut down in 2022, this page remains as a memory of our company and on the resumes of our team.Business intelligence is ready for a change. We don't believe the world needs any more dashboards, charts or data warehouses. What leaders need today is help to make better use of the tools they already have. That is what we do at Outlier: we improve the relationship between people and their data.We believe that success in life and success in business are not separate things, but intertwined as part of our lives. It is important to us that the journey we take with our company is as positive as the destination we hope to reach.
- Series B
- 7.3k employees
- Founded 2015
8
GitHub· San Francisco, California, United States
As the global home for all developers, GitHub is the complete AI-powered developer platform to build, scale, and deliver secure software. Over 100 million people, including developers from 90 of the Fortune 100 companies, use GitHub to build amazing things together across 330+ million repositories. With all the collaborative features of GitHub, it has never been easier for individuals and teams to write faster, better code.
- Series B
- 6.8k employees
- Founded 2008
9
Shipt· Birmingham, Alabama, United States
Through a community of shoppers and a convenient app, Shipt provides personal shopping and delivery and is available to 80% of households in more than 5,000 U.S. cities. Shoppers go above and beyond, communicating in real time about preferences and substitutions. A curated marketplace of retailers, Shipt offers access to a variety of stores and product categories including fresh foods, household essentials, wellness products, office and pet supplies. Shipt is an independently operated, wholly owned subsidiary of Target Corp. Founded and headquartered in Birmingham, Alabama, Shipt also maintains an office in San Francisco. For more information, visit Shipt.com.
- Series B
- 6.5k employees
- Founded 2014
10
WhatsApp· Menlo Park, California, United States
WhatsApp is a fast, simple and reliable way to talk to anyone in the world. More than 1.5 billion people across 180+ countries use WhatsApp to stay in touch with friends and family, anytime and anywhere. WhatsApp is not only free but also available on multiple mobile devices and in low connectivity areas — making it accessible and reliable wherever you are. It's a simple and secure way to share your favorite moments, send important information or catch up with a friend. WhatsApp helps people connect and share no matter where they are in the world.For many people in the world WhatsApp is a lifeline. We're looking for engineers, designers, researchers, product managers, technical program managers, customer ops, consumer marketing, and more. Come join our teams and make impact at scale.
- Series B
- 5.9k employees
- Founded 2009

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Find engineers and founders at Series B Developer tools companies

Series B Developer tools companies are some of the most active hirers in the market. The list above ranks the largest Developer tools companies whose latest disclosed round is Series B, by current headcount, drawn from public LinkedIn and Crunchbase records. Across 1,707 matching companies, you’ll find senior engineers, founding designers, and operators worth tracking.

Companies at this stage in Developer tools share a profile: a working product, fresh capital, and a hiring plan that wants senior people yesterday. Looking at headcount, last round, and HQ side by side gives you a quick read on where Developer tools talent is concentrating right now.

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How this list is built

Refolk pulled Developer tools companies whose latest disclosed funding round is Series B from public LinkedIn and Crunchbase records, ranked them by current employee count, and kept those with at least 5 employees. The list refreshes monthly.

Last refreshed: Sun, 18 Oct 2026 10:36:23 GMT

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The list draws on the public company graph - headcount and growth signals, funding history, and recency. The criteria chips at the top show exactly which filters produced it, and the methodology section explains the ranking.

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