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Joonas Lehtinen

@joonas

Web. AI. Open Source. Enterpreuner. Vaadin Co-founder. CS PhD. SF Bay Area. Dad & husband.

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06.05.2023
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Latest posts by Joonas Lehtinen @joonas

It took way too long, sorry.

10.09.2025 02:06 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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We taught AI a new modality @vaadin.com β€” UI

In Computer–Human Interaction, the AI decides what it needs from a human, and builds the UI on the fly β€” adapting in real-time as the human interacts.

Try it β†’ computerhumaninteraction.com

10.09.2025 02:03 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

THANK YOU for reporting!
Look like some pages work and some return 503.

31.08.2025 22:58 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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10 years of building Web Components: the story of <vaadin-combo-box> A story about building Vaadin web components

10 years of building Web Components at @vaadin.com: celebrating the "anniversary" of <vaadin-combo-box>!

Check out this blog post to learn about our journey and how we finally migrated to @lit.dev:

dev.to/webpadawan/1...

27.08.2025 16:16 πŸ‘ 20 πŸ” 4 πŸ’¬ 2 πŸ“Œ 0
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πŸš€ Updated Vaadin MCP

✨ Combines semantic + keyword search with reranking

πŸ› οΈ MCP Tools Available:
πŸ“š get_vaadin_primer - Vaadin fundamentals & best practices
πŸ” search_vaadin_docs - Search Vaadin docs
πŸ“„ get_full_document - Complete doc retrieval
🏷️ get_vaadin_version - Latest stable version info

29.07.2025 12:39 πŸ‘ 6 πŸ” 1 πŸ’¬ 3 πŸ“Œ 0

You might not want to commit generated folder...

18.07.2025 18:43 πŸ‘ 3 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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Hilla and Kafka. Part 3: Kafka Streams Using Kafka Streams and Interactive Queries to consume, aggregate and query streaming data in the Hilla backend and visualize the data in the Hilla frontend in a reactive way.

New blog post: Using Kafka Streams and Interactive Queries to consume, aggregate and query streaming data in business web apps built with #Hilla (by @vaadin.com).

rene-wilby.de/en/blog/hill...

16.07.2025 07:25 πŸ‘ 7 πŸ” 4 πŸ’¬ 1 πŸ“Œ 0

I would like to avoid any politics β€” it is a slippery slope that will distract focus quick.

15.07.2025 20:11 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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Chinese, Finnish, German, and Spanish translations for
@vaadin documentation is now live. More languages will be added in August.

15.07.2025 13:31 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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I'm starting a new live coding series!
🧠 Build a local AI chatbot in pure Java
βš™οΈ With Spring AI, Vaadin UI & Docker
πŸ§™ It's a text adventure game with stats, magic, inventory, and AI-generated ASCII art.

Follow along if you’re into #Java + #AI!
#SpringBoot #Vaadin #LiveCoding

04.07.2025 00:00 πŸ‘ 9 πŸ” 4 πŸ’¬ 3 πŸ“Œ 0

Hard to reason with that. Hopefully the organization will learn at some point of time that modern software development practices save money and deliver better results.

Then you can reverse the rewrite commit :)

25.06.2025 18:55 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Vaadin Copilot AI Pair Coder Prototype
Vaadin Copilot AI Pair Coder Prototype YouTube video by vaadinofficial

Vibe coding feature (prototype) in @vaadin.com Copilot is magical. Rudolf the red nose agent really builds the full Spring app for you…

youtu.be/rBX_ZPvPfN0

29.03.2025 02:48 πŸ‘ 3 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0

Thank you!

20.03.2025 23:14 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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24/7 Flow with Vaadin 24.7 | Vaadin Vaadin 24.7 is here! Simplify upgrades, enhance security, and accelerate development. Upgrade now and keep coding 24/7!

Vaadin 24.7 = faster dev, stronger security, smarter automation!

βœ… Flow: Resilient server-client messaging
βœ… Hilla: React 19 support
βœ… Copilot: Custom components & automation
βœ… Control Center: Now GA!

+ more updates!

πŸ”— See what's new: vaadin.com/blog/vaadin-...

19.03.2025 15:21 πŸ‘ 2 πŸ” 4 πŸ’¬ 0 πŸ“Œ 1
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How do teams choose the right tech for #Java apps?

We’re running a quick surveyβ€”not just on what tools teams use, but why. Your insights will help the community make better decisions in 2025!

πŸ”— Join the survey: survey.survicate.com/8dd6ee2a0565...

27.02.2025 10:04 πŸ‘ 3 πŸ” 7 πŸ’¬ 0 πŸ“Œ 1

It’s disheartening to see such tone-deaf cruelty from an official White House communication.

20.02.2025 00:20 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

And it is not even that: $2.5M of the $8M contract _limit_ was already spent. Thus, the maximum saving would have been the remaining $5.5M.

In other words, actual saving is less than 0.07% of what DOGE claimed.

20.02.2025 00:15 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Kahneman’s β€œThinking, Fast and Slow” has a parallel in AI:
β€’ System 1: LLMs produce a rapid stream of thought
β€’ System 2: Reasoning models think before answering

06.02.2025 00:13 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Vaadin Directory Wrapped 2024
Vaadin Directory Wrapped 2024 YouTube video by Sami Ekblad

Vaadin community releases a plugin update daily in average and adds a completely new plugin almost weekly. With over 2000 plugins to choose from, community really elevates Vaadin. This is Open Source in practice.

Kudos @samiekblad.bsky.social for leading Directory!

youtu.be/D5JbB5nf3qk?...

26.01.2025 08:43 πŸ‘ 1 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0
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πŸ€– @tzolov.bsky.social created a cool demo showing off OpenAI gpt-4o-audio and Spring AI and said it could use a better interface. Ask, and you shall receive. Introducing Marvin, the paranoid UI πŸ˜†
github.com/marcushellbe...

06.12.2024 00:32 πŸ‘ 10 πŸ” 5 πŸ’¬ 0 πŸ“Œ 0
Full stack level up: what’s next for Vaadin by Joonas Lehtinen - Vaadin Create 2024
Full stack level up: what’s next for Vaadin by Joonas Lehtinen - Vaadin Create 2024 YouTube video by vaadinofficial

One year ago, I rejoined Vaadin to help guide the product in a fresh new direction. I'm immensely proud of what our team has achieved over the past 12 months. Five weeks ago, I had the privilege of summarizing what we build at our annual user conference.

12-minute recap:
youtu.be/lWbLQda_aPU?...

04.12.2024 23:01 πŸ‘ 3 πŸ” 2 πŸ’¬ 1 πŸ“Œ 0
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Figma to Vaadin | Figma Generate Vaadin UI code by copy-pasting designs from Figma. Works with Vaadin Flow (Java) and Hilla (React). This file documents the feature and offers few sample UI's that can be used for testing or ...

Copy-paste from Figma to @vaadin.com

www.figma.com/community/fi...

06.11.2024 15:38 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Hello world!

06.05.2023 05:47 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0