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Show HN: I built a tiny LLM to demystify how language models work

https://github.com/arman-bd/guppylm
200•armanified•4h ago•14 comments

Show HN: YouTube search barely works, I made a search form with advanced filters

https://playlists.at/youtube/search/
142•nevernothing•4h ago•93 comments

Show HN: Gemma Gem – AI model embedded in a browser – no API keys, no cloud

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37•ikessler•5h ago•4 comments

Show HN: Modo – I built an open-source alternative to Kiro, Cursor, and Windsurf

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29•mohshomis•5h ago•2 comments

Show HN: Mdarena – Benchmark your Claude.md against your own PRs

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15•hudsongr•5h ago•1 comments

Show HN: Multi-agent coding assistant with a sandboxed Rust execution engine

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Show HN: Open-source ontology – SEC fund filings

https://github.com/getfundflow/gff-schema
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Show HN: A game where you build a GPU

https://jaso1024.com/mvidia/
903•Jaso1024•1d ago•179 comments

Show HN: OsintRadar – Curated directory for osint tools

https://osintradar.com/
70•lexalizer•23h ago•6 comments

Show HN: jsoncompat – a library to detect/fuzz breaking changes in JSON schemas

https://jsoncompat.com/
3•rogaos•3h ago•0 comments

Show HN: Dot-Globe – React component that renders NASA night-light data

https://www.kurt.xyz/dot-globe
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Show HN: Contrapunk – Real-time counterpoint harmony from guitar input

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112•waveywaves•1d ago•47 comments

Show HN: M. C. Escher spiral in WebGL inspired by 3Blue1Brown

https://static.laszlokorte.de/escher/
158•laszlokorte•1d ago•27 comments

Show HN: I built a small app for FSI German Course

https://detawk.com/
48•syedmsawaid•3d ago•14 comments

Show HN: Grug – Claude Code Skill Inspired by the Grug Brained Developer

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Show HN: Runfra – Decentralized GPU cluster designed for bulk generation

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4•spencer9714•7h ago•1 comments

Show HN: Where Is Artemis?

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6•larsmoa•7h ago•0 comments

Show HN: ACE – A dynamic benchmark measuring the cost to break AI agents

https://fabraix.com/blog/adversarial-cost-to-exploit
7•zachdotai•7h ago•3 comments

Show HN: I made open source, zero power PCB hackathon badges

https://github.com/KaiPereira/Overglade-Badges
153•kaipereira•1d ago•16 comments

Show HN: sllm – Split a GPU node with other developers, unlimited tokens

https://sllm.cloud
179•jrandolf•1d ago•89 comments

Show HN: I built a frontpage for personal blogs

https://text.blogosphere.app/
768•ramkarthikk•2d ago•193 comments

Show HN: Orcastrate – Sync GitHub Actions workflows across repos via templates

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Show HN: Genetic algorithm engine that evolves trading strategies

https://github.com/NeuZhou/finclaw
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Show HN: Apfel – The free AI already on your Mac

https://apfel.franzai.com
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Show HN: Arbory – Native iOS dashboard and widgets for Plausible Analytics

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Show HN: TurboQuant-WASM – Google's vector quantization in the browser

https://github.com/teamchong/turboquant-wasm
160•teamchong•1d ago•6 comments

Show HN: Ragot – a front end runtime built around lifecycle and ownership

https://github.com/BleedingXiko/RAGOT
2•BleedingXiko•10h ago•1 comments

Show HN: Fabro – open-source dark software factory

https://github.com/fabro-sh/fabro
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Show HN: Sigil – A new programming language for AI agents

4•inerte•10h ago•0 comments

Show HN: I built a tool to show how much ARR you lose to FX fees

https://fixmyfx.com
4•TaniaBell_PD•11h ago•1 comments
Open in hackernews

Show HN: Fahmatrix – A Lightweight, Pandas-Like DataFrame Library for Java

https://github.com/moustafa-nasr/fahmatrix
46•mousomashakel•10mo ago
Hey HN, I’ve built Fahmatrix, a minimal, fast Java library for working with tabular data — inspired by Python’s pandas, but designed for performance and simplicity on the JVM.

After working extensively with Python’s data stack, I often ran into limitations related to speed, especially in larger or long-running data workflows. So I built Fahmatrix from scratch to offer similar APIs for manipulating CSVs, performing summary statistics, slicing rows/columns, and more — but all in Java.

Features:

Lightweight and dependency-free

CSV/TSV import with auto-headers

Series/DataFrame structures (like pandas)

describe(), mean(), stdDev(), percentile() and more

Fast parallel operations on numeric columns

Java 17+ support

Docs: https://moustafa-nasr.github.io/Fahmatrix/ GitHub: https://github.com/moustafa-nasr/fahmatrix

I’d love feedback from the Java and data communities — especially if you’ve ever wanted a simple dataframe utility in Java without needing full-scale ML libraries.

Happy to answer any questions!

Comments

rickette•10mo ago
Congrats on putting this out there. There isn't a de facto pandas-like library in Java like you said. But for Kotlin there is: https://github.com/Kotlin/dataframe
mousomashakel•10mo ago
Thanks so much! Yep, I’ve seen the Kotlin DataFrame lib — very elegant. Fahmatrix is meant for plain Java users who want similar capabilities without switching ecosystems. Appreciate the support!
uwemaurer•10mo ago
Always great to see efforts to make working with data frames easier. Here are some similar data frame libraries for Java:

https://github.com/jtablesaw/tablesaw

https://github.com/dflib/dflib

My preferred way is just use duckdb java API. I didn't see anything better in performance/efficiency. Also a SQL query is often easier to write

theanonymousone•10mo ago
Yes. It has bothered me for a long time too. Maybe the best mix is a dataframe library with basic operations (column select, non-null etc), which also allows SQL for more complex stuff?
radus•10mo ago
Polars and duckdb interoperate nicely and can enable this flexibility
theanonymousone•10mo ago
Does Polars have a Java library?
mousomashakel•10mo ago
Totally agree that SQL can be the best tool for many jobs. My goal with Fahmatrix is to serve the opposite niche: where devs want something that's Java-native, procedural, and simple without reaching for an external engine. SQL support or DSL might come later though — I see the appeal.
theanonymousone•10mo ago
Sure. So maybe notehr comment would be to make it (particularly the Series class), as compatible with Java Streams as possible.

Next step would likely be compatibility with popular libraries such as Apache Commons Math: https://commons.apache.org/proper/commons-math/userguide/sta...

mousomashakel•10mo ago
Thanks! I'm aware of those great projects. Fahmatrix aims to offer a lightweight, dependency-free alternative that’s easy to embed in any Java app. DuckDB is super impressive, especially for SQL-heavy tasks — but my goal is more about a native, fluent API for those who prefer direct Java code over SQL.
skanga•10mo ago
What about Tablesaw, Apache Arrow? How does this compare ...
mousomashakel•10mo ago
Good question. I’ll publish benchmarks soon, but the core difference is that Fahmatrix is fully Java, no JNI, and minimalistic — ideal for small projects or environments like Android. Tablesaw and Arrow are more powerful, but heavier. Fahmatrix aims to be the “just enough” middle ground.
owlstuffing•10mo ago
Nice!

I’m currently using manifold-sql with duckdb for this.

mousomashakel•10mo ago
Thanks! That’s a great combo — manifold-sql + duckdb gives you strong typing with powerful SQL under the hood. Fahmatrix is aiming to complement that approach for cases where you want quick, native Java code without SQL — e.g., when building data flows or custom logic inline. Would love to hear if you’ve hit any pain points that a Java-native approach could help with.