Dev tools · alternatives · 2026

24 alternatives to Mosaic – A Kotlin framework for cleaner back end code

Backend APIs often grow into large orchestration classes full of duplicated calls and manual concurrency. I’ve been working on Mosaic, a Kotlin framework that composes responses out of small, request-scoped “tiles.” Each tile runs once per request, dependencies resolve automatically, and independent tiles execute in parallel without boilerplate. It’s still early (v0.2.0), but working today for caching, concurrency, and testability. Curious to hear feedback on the approach. GitHub: https://github.com/Nick-Abbott/Mosaic Maven Central: org.buildmosaic:mosaic-core:0.2.0

Mosaic is a Kotlin framework for building backend APIs that breaks complex orchestration logic into small, reusable "tiles." Each tile executes once per request with automatic dependency resolution, and independent… Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes.

1
Mosaic – A declarative, front-end JavaScript library for building UIs▲63
🎨 A front-end JavaScript library for building user interfaces! - Authman2/Mosaic
2019 · github.com · its alternatives →
2
I finished v5 of a JVM framework I've spent spent half a decade making▲377
ForewordJavalin is a Java and Kotlin web framework which focuses on simplicity and Java/Kotlin interoperability.It supports WebSockets and HTTP3, and it uses...
2022 · javalin.io · its alternatives →
3
Crust – A CLI framework for TypeScript and Bun▲95
We've been building Crust (https://crustjs.com/), a TypeScript-first, Bun-native CLI framework with zero dependencies. It's been powering our core product internally for a while, and we're now open-sourcing it. The problem we kept running into: existing CLI frameworks in the JS ecosystem are either minimal arg parsers where you wire everything yourself, or heavyweight frameworks with large dependency trees and Node-era assumptions. We wanted something in between. What Crust does differently: - Full type inference from definitions — args and flags are inferred automatically. No…
Mar 2026 · github.com · its alternatives →
4
Restate – Low-latency durable workflows for JavaScript/Java, in Rust▲185
We'd love to share our work with you: Restate, a system for workflows-as-code (durable execution). With SDKs in JS/Java/Kotlin and a lightweight runtime built in Rust/Tokio. https://github.com/restatedev/ https://restate.dev/ It is free and open, SDKs are MIT-licensed, runtime permissive BSL (basically just the minimal Amazon defense). We worked on that for a bit over a year. A few points I think are worth mentioning: - Restate's runtime is a single binary, self-contained, no dependencies aside from a durable disk. It contains basically a…
2024 · restate.dev · its alternatives →
5
Horizon 1.0▲312
Realtime, open-source backend for JavaScript apps
2016 · sequence.xyz · its alternatives →
6
Mosaic – Use multiple iPhones as one big screen▲106
Mosaic’s mission is to be the leading platform for reliable research, market information, and discussions on cryptoassets and related areas.
2013 · mosaic.io · its alternatives →
7
Run globally distributed full-stack apps on high-performance MicroVMs▲98
Hi HN! We’re Yann, Edouard, and Bastien from Koyeb (https://www.koyeb.com/). We’re building a platform to let you deploy full-stack apps on high-performance hardware around the world, with zero configuration. We provide a “global serverless feeling”, without the hassle of re-writing all your apps or managing k8s complexity [1]. We built Scaleway, a cloud service provider where we designed ARM servers and provided them as cloud servers. During our time there, we saw customers struggle with the same issues while trying to deploy full-stack applications and APIs resiliently. As…
2023 · koyeb.com · its alternatives →
8
Mosaic▲8
A declarative, front-end JavaScript library for building UIs
2019 · github.com · its alternatives →
9
Komorebi – A tiling window manager for Windows 10/11 written in Rust▲229
A tiling window manager for Windows 🍉. Contribute to LGUG2Z/komorebi development by creating an account on GitHub.
2022 · github.com · its alternatives →
10
Artifact Keeper – Open-Source Artifactory/Nexus Alternative in Rust▲166
I'm a software engineer who keeps getting pulled into DevOps no matter how hard I try to escape it. I recently moved into a Lead DevOps Engineer role writing tooling to automate a lot of the pain away. On my own time outside of work, I built Artifact Keeper — a self-hosted artifact registry that supports 45+ package formats. Security scanning, SSO, replication, WASM plugins — it's all in the MIT-licensed release. No enterprise tier. No feature gates. No surprise invoices. Your package managers — pip, npm, docker, cargo, helm, go, all of them — talk directly to it using their native…
Feb 2026 · github.com · its alternatives →
11
Go Actor Model, fast distributed actors for Golang▲115
Proto Actor - Ultra fast distributed actors for Go, C# and Java/Kotlin - asynkron/protoactor-go
2016 · github.com · its alternatives →
12
Ion, a Rust/Tokio powered JavaScript runtime for embedders▲30
A Positively Charged JavaScript Runtime . Contribute to alshdavid-public/ion development by creating an account on GitHub.
2025 · github.com · its alternatives →
13
Open sourcing a data flow engine for Clojure/Script▲116
2019 · domino-clj.github.io · its alternatives →
14CP
Clojure parser and core library in JavaScript, live on CodeCombat▲57
2014 · vickychijwani.github.io · its alternatives →
15
My first open-source project release – RandomJson▲56
Provides a Kotlin/Java library to create a random json string - mangatmodi/RandomJson
2019 · github.com · its alternatives →
16
Keystone▲125
We kept hitting the same wall: you clone some arbitrary repo and just want it to run without any configuration work. So we built Keystone, an open source tool that spins up a Modal sandbox, runs Claude Code inside it, and produces a working .devcontainer/ config (Dockerfile, devcontainer.json, test runner) for any git repo. We build on the dev container standard, so the output works with VS Code and GitHub Codespaces out of the box. Main use cases: reproducible dev/CI environments, self-describing repos, and safely sandboxed coding agents. Our goal is to encourage all repos to…
Mar 2026 · github.com · its alternatives →
17
Javalin, a Java/Kotlin REST API Framework▲50
Javalin - A lightweight Java and Kotlin web framework. Create REST APIs in Java or Kotlin easily.
2017 · javalin.io · its alternatives →
18
Kodingless▲100
Turn database schema into Backend API source codes
2023 · its alternatives →
19
Redux-Tiles – library to deal with verbosity of Redux▲35
Composable way to create less verbose Redux code. Contribute to Bloomca/redux-tiles development by creating an account on GitHub.
2017 · github.com · its alternatives →
20
Desktop app displaying files on a 2D canvas▲45
Hey all! I always wanted to arrange my text/markdown/pdf files on a 2D canvas and visualize them without opening all the windows. An extra feature I added is also visualizing folders within - so kind of a 3D visualization? It was also important to be an offline desktop app, rather than online tool like Miro or Mural, because once I edit files in Sublime or AdobePDF then I want changes to sync in the canvas right away. Some technical points and lessons learned: being Android developer helped a lot with this project since I used Kotlin Multiplatform with Compose Desktop renderer…
2024 · limandoc.com · its alternatives →
21
Http4k: Server as a Function. In Kotlin. Typesafe. Without the Server▲29
An overview of the Kotlin
2017 · http4k.org · its alternatives →
22
Voiden – an offline, Git-native API tool built around Markdown▲48
Hi HN, We have open-sourced Voiden. Most API tools are built like platforms. They are heavy because they optimize for accounts, sync, and abstraction - not for simple, local API work. Voiden treats API tooling as files. It’s an offline-first, Git-native API tool built on Markdown, where specs, tests, and docs live together as executable Markdown in your repo. Git is the source of truth. No cloud. No syncing. No accounts. No telemetry.Just Markdown, Git, hotkeys, and your damn specs. Voiden is extensible via plugins (including gRPC and WSS). Repo:…
Feb 2026 · github.com · its alternatives →
23
A working reference implementation of context engineering▲46
I've been presenting at local meetups about Context Engineering, RAG, Skills, etc.. I even have a vbrownbag coming up on LinkedIn about this topic so I figured I would make a basic example that uses bedrock so I can use it in my talks or vbrownbags. Hopefully it's useful.
Apr 2026 · github.com · its alternatives →
24AS
A sample project for Golang▲57
I have been using golang at work and personally for more than 2 years now. A problem i faced when I started and the problem new gophers even today is how to structure the project. Most (if not all) golang tutorials seem to be very simple and do not describe how to structure a large application. Following project is an attempt to Showcase a manageable project layout for services in golang. https://github.com/spy16/droplets This project is far from complete. Would like to hear some feedback from the community before continuing on this.
2018 · its alternatives →

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