Y Combinator S19
YC Summer 2019 developer tools companies
Customer data collection, safeguarding, & activation for healthcare
120 people · San Francisco, CA, USA · Developer Tools · YC page
The design system layer for coding agents
55 people · London, England, United Kingdom · Developer Tools, Design Tools · YC page
The Unified API for Business Financial Data
24 people · New York City, NY, USA · Developer Tools, Fintech · YC page
Pull Requests as a Service
19 people · San Francisco, CA, USA · Developer Tools · YC page
Open-source, self-hosted, session replay tool for developers.
11 people · New York City, NY, USA · Developer Tools, Open Source · YC page
The Operating System for Edge Computing
11 people · San Francisco, CA, USA · Developer Tools, Open Source · YC page
Vibe code games.
10 people · San Francisco, CA, USA · Developer Tools, Generative AI, Machine Learning, Gaming · YC page
Build UI fast.
1 person · San Francisco, CA, USA · Developer Tools · YC page
A better data science notebook.
San Francisco, CA, USA · Developer Tools, Machine Learning · YC page
Modern user-focused observability built on OpenTelemetry
62 people · Los Angeles, CA, USA · Open Source, Data Engineering, AI · YC page
The fastest way for developers to build notifications for their app.
35 people · San Francisco, CA, USA · Developer Tools, Messaging · YC page
Spark-on-Kubernetes Data Engineering Platform
25 people · Paris, Île-de-France, France · Open Source, Data Engineering · YC page
SQL editor for teams
15 people · San Francisco, CA, USA · Developer Tools, Analytics · YC page
Bun is an incredibly fast all-in-one JavaScript toolkit
13 people · San Francisco, CA, USA · Developer Tools, Open Source · YC page
Supercharged deployment previews for all.
4 people · San Francisco, CA, USA · Developer Tools · YC page
The only platform that can prep data to answer EVERY question you…
8 people · New York City, NY, USA · Analytics, Big Data, Data Engineering · YC page
The next generation CMS built for mobile apps
5 people · New York City, NY, USA · Developer Tools, Design Tools · YC page
An Open Source dependency security tool that is smarter than the rest
4 people · Seattle, WA, USA · Developer Tools, DevSecOps, Security Orchestration, Automation and Response (SOAR), Security · YC page
Turn any website into an API
3 people · Paris, Île-de-France, France · Developer Tools, Machine Learning, Robotic Process Automation · YC page
Improve your browsing experience by staying organized and intentful
3 people · San Francisco, CA, USA · Developer Tools · YC page
The Self-Hosting Company
2 people · San Francisco, CA, USA · Hardware, Community, Kubernetes · YC page
FAQ
How many developer tools companies are in YC Summer 2019 (S19)?+
21 launched companies in YC Summer 2019 carry a developer-tools or infrastructure tag in YC's directory (snapshot of 2026-10-20); 9 are active. Companies that have not launched publicly on YC's site yet are not counted.
What are the top tags in YC S19 dev tools?+
Developer Tools (17), Open Source (6), Data Engineering (3), Machine Learning (3), AI (2). 6 of 21 are tagged open source.
Which YC S19 dev-tool companies are the largest?+
By team size on YC's directory: Freshpaint, zeroheight, Rutter.
← Winter 2020Winter 2019 →All YC dev-tool companiesOpen-source YC companies
Source: Y Combinator's public company directory via the unofficial mirror yc-oss/api. DevHunt is not affiliated with Y Combinator.