Tejas Kumar: AI Engineer, Speaker, Author of Fluent React

I speak at conferences.

80 talks at 64 events, 2013 to 2026. Here they all are.

Tejas Kumar is an AI Engineer at IBM, based in Berlin, Germany, who has been building on the web for over 25 years. He is the best selling author of Fluent React, published by O'Reilly, he hosts the ConTejas Code podcast, and he has given 80 recorded talks at 64 events since 2013. His work at Spotify, G2i, Vercel, Xata and DataStax came before IBM, which acquired DataStax. He is also an angel investor in early stage startups, 3 of which have since been acquired.

Short bio

Every talk, the topics I speak on, and how to book me is on the speaking page. If you want the longer story, start here.

Here are some things people say about my talks.

Josh W. Comeau@JoshWComeau
I’ve said it before, but @tejaskumar_ has the most amazing energy when he speaks (and also in real life!). Amazing talk as usual about the tradeoffs React makes and why they’re really pretty good compromises.
Jun 1, 2023View on
Mark Dalgleish@markdalgleish
.@tejaskumar_ is such a charismatic speaker.
Oct 20, 2023View on
David K 🎹@davidkpiano
Whenever @tejaskumar_ live codes in a presentation, it's absolutely stunning. Feels like he can turn almost anything into a 2-minute demo.
May 7, 2022View on
Cassidy@cassidoo
This talk by @tejaskumar_ is so inspiring. He’s got hemophilia, and he built an app that has a data visualization of the half life of his medicine! #DinoJS
Jun 20, 2019View on
Francesco@FrancescoCiull4
I met Tejas Kumar !!!!
An amazing speaker and a super friendly, funny person in real life!
Thanks for wearing my sticker @tejaskumar_!!
Nov 20, 2022View on
swyx@swyx
dude. i wish i had your energy, technical, and speaking skills! I dont know how you do it.
Sep 26, 2019View on

I host a podcast.

I talk to world experts in web engineering, and I lecture. Search across every episode with custom AI.

98 episodes, weekly

Here are some things people say about my podcast.

Josh Goldberg 💖@JoshuaKGoldberg
There have been too many people on ConTejas recently I really really want to hear from: @ladyleet, @alexnmoldovan, @MichelleBakels, @gabe_g2i... ugh.
I'm getting FOMO from the last 2 weeks of just one podcast. You did this to me @tejaskumar_ :(
Sep 26, 2024View on
Michael Wheatfill@mwheatfill
I love the long format Tejas. It kind of reminds me of the Lex Friedman of web dev focused podcasts. The thoughtful questions and depth of answers was awesome to experience.
Mar 4, 2024View on
Guillermo Rauch@rauchg
Had a great podcast with @tejaskumar_ on:
◆ the physics of networks
◆ why move away from edge rendering
◆ fast vs slow global data transfer
◆ latency numbers every engineer (@jeffdean) and web engineer (@cramforce) should know
◆ RSC, PPR & Streaming
Dropping soon!
Apr 27, 2024View on
Shriram Balaji@shrirambalaji
highly recommend watching this video, if you haven’t, definitely needs more views!
youtu.be/G-Js3CcD000?si=ufrOBE58U9q3ISSh
@tejaskumar_ has the ability to break things down calmly, and explain how computers work - from subatomic particles, electricity, hardware, software, firmware to servers and more.
Mar 13, 2024View on
Yoav Ganbar (🥑 Builder.io/Qwik)@HamatoYogi
Just finished listening to @tejaskumar_'s new podcast.
The first one is jam packed with tons of knowledge and great insights on what's going on in the web and software in general.
Awesome to hear him taking time to talk about @QwikDev especially 🙂
Highly recommend a listen 👌🏾
Mar 5, 2024View on
Atila Fassina@AtilaFassina
This was one of the most fun conversations I’ve had in a long time!
@tejaskumar_ is a great podcast host and an even better conversation partner!! ❤️
Mar 15, 2024View on

I wrote a book.

Fluent React is a deep dive on how React works on the inside, curated by me and published by O'Reilly.

O'Reilly

It will help you understand React's internal mechanisms more deeply and unlock greater levels of fluency.

It was reviewed by a number of peers including the React core team, experts, and friends.

More about Fluent React and how React actually works.

Buy the book

Here are things people say about this book.

Una 🇺🇦@Una
I think I need to read @tejaskumar_'s new book 😅
Great talk about optimizing React w/useDefferedValue and useTransition at #ReactParis
Mar 22, 2024View on
Michelle Bakels@MichelleBakels
I got dropped into web dev via corporate mandate 6 yrs ago, so I love that Fluent React begins by outlining the ecosystem of the time — something I was largely disconnected from.
This context has helped me appreciate everything I’ve learned so much more. @tejaskumar_ 🙏
Mar 23, 2024View on
Daniel Afonso@danieljcafonso
Fluent React is #1 best selling. As it should be 😁
Mar 23, 2024View on
Amanda 🌿@hey_amandam
V excited for this. As someone who has used React for years but never as my only focus, it will be interesting to see how this deepens knowledge for me
I'm a huge fan of @tejaskumar_ as a person and enjoy his teaching style so I expect to feel more of that same vibe in this book
Mar 14, 2024View on
Nisarg Parikh@nisargparikh90
Fluent React by @tejaskumar_ is an amazing book. Learning React by reading a book is a completely new experience.
Mar 7, 2024View on
Josh W. Comeau@JoshWComeau
Tejas previewed some of his book in his React Paris talk and it's seriously great. Goes deep into advanced topics.
Just picked up a copy for myself 😄
Mar 23, 2024View on

I invest in startups.

I make angel investments in early stage startups, sometimes with cash, and other times as an advisor.

6 companies, 3 exits

Pitch me your startup

I write small checks, and I mostly follow people whose judgment I trust. Guillermo Rauch, David Khourshid and Swyx invest early too, and I am usually following one of them into the round.