Life & fun · alternatives · 2026
24 alternatives to LemmaScript, a verification toolchain for TypeScript via Dafny
I created LemmaScript to compile TypeScript to a verification backend (Dafny or Lean) and prove properties on the systematically derived model. I'll keep developing this, but I have a few case studies already, and it looks quite promising, with the caveat that each case study pushed the development of the core further. I can support both greenfield and brownfield projects, and in many cases, verification can be in-place: the TypeScript source is just annotated and verified independently but runs as is.
Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes.
- 1
Hi friends, I started casually working on scrapscript in 2015. I built a few compilers over the years to test out various ideas/implementations, and I think I'm finally happy with the overall design. The code is not public yet. Email me at [email protected] if you're interested in joining the core team later this year. Let me know if you have any questions or feedback :)
2023 · scrapscript.org · its alternatives →
- 2
TypeScript 6.0▲156The Playground lets you write TypeScript or JavaScript online in a safe and sharable way.
Mar 2026 · typescriptlang.org · its alternatives →
- 3
🛫 Zero-codegen, no-compile TypeScript `type` inference from protobuf `message`s - nathanhleung/protobuf-ts-types
2025 · github.com · its alternatives →
- 4
Open sourcing Ezno's checker and trying out / previewing the JavaScript type checker today
2023 · github.com · its alternatives →
- 5
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 →
- 6
TypeScript as a proof assistant. GitHub Gist: instantly share code, notes, and snippets.
2025 · gist.github.com · its alternatives →
- 7
The from-scratch guide to building large language models in NodeJS.
8d ago · book.humanexperiences.io · its alternatives →
- 8
Hello, folks. I'm Jiang, the author of ESInfer. I love writing Javascript because it has a prosperous ecosystem and is quick to get my hands dirty. However, sometimes it's painful when the flow is not fast to follow due to the lack of a type system. To solve this, I wrote ESInfer, a statical inference tool, to automatically type check and generate type annotations for Javascript. It works with pure Javascript without any add-ons to the language or user-space code and supports highly dynamic features, such as the modification of prototypes. It is still in the very early stage, which offers…
2022 · esinfer.com · its alternatives →
- 9
Let JSON play nicely with Typescript. Contribute to ostrowr/ts-json-validator development by creating an account on GitHub.
2019 · github.com · its alternatives →
- 10
- 11
Build Typed GraphQL Queries in TypeScript without the code generation - acro5piano/typed-graphqlify
2018 · github.com · its alternatives →
- 12
Hi all, Aram and Eduard here - authors of Modelence (https://github.com/modelence/modelence), an all-in-one backend platform for teams that love TypeScript + MongoDB. Think Supabase, but for MongoDB: auth, cron jobs, email, monitoring, without glue code before you can ship. As Karpathy (and many of us) noted, getting from prototype to production is mostly painful integration work. The pieces exist, but stitching them together reliably is the hard part: https://x.com/karpathy/status/1905051558783418370. YC AI Startup School talk about this -…
2025 · github.com · its alternatives →
- 13
Compile JSON Schema to TypeScript type declarations - bcherny/json-schema-to-typescript
2017 · github.com · its alternatives →
- 14
:icecream: vanillatype - Lightweight runtime types for vanilla JS and Node - crisdosaygo/vanillatype
2020 · github.com · its alternatives →
- 15
Framework for specifying and proving properties—such as robustness, fairness, and interpretability—of machine learning models using Lean 4. - fraware/leanverifier
2025 · github.com · its alternatives →
- 16AS
Took a stab at building my own string diffing JS package. I built an interactive demo for TypeIt’s website (https://typeitjs.com/build-your-own) a while back. The approach I took to handle user input necessitated a way to calculate the difference between the versions of a user’s text input. I searched around for a package to help me out and found a couple of good ones (like fast-diff), but I either didn’t really like their API or didn’t want to take on a huge new dependency. Instead, I thought I’d give it a shot myself (famous last words). I dove into it having no real formal…
2022 · its alternatives →
- 17
I started writing this book 10 years ago in JavaScript, got through a few chapters (asymptotic notation, basic techniques, start of sorting), and then abandoned it. Recently I picked it back up, converted everything to TypeScript, and used AI (Zenflow [1] + Claude Opus 4.6) to complete the remaining chapters. I provided the structure, direction, and initial chapters; the AI generated the bulk of the remaining content under a spec-driven workflow. The book covers roughly a first 1-2 year CS curriculum: sorting, dynamic programming, graph algorithms, trees, heaps, hash tables, and more. All…
Mar 2026 · amoilanen.github.io · its alternatives →
- 18
UI as finite-state machine . Contribute to stepanvanzuriak/Finite development by creating an account on GitHub.
2018 · github.com · its alternatives →
- 19
- 20
Lightweight, Chainable TypeScript Validation
Oct 2025 · typyn.pages.dev · its alternatives →
- 21
Elegant, highly efficient data validation for JavaScript. - lucono/xtypejs
2015 · github.com · its alternatives →
- 22AJ
I've been building a web UI library for a side project of mine. I thought it might be useful to others, so I'm releasing it as open source. To put it simply, I realized that most of my pain points with React come from its declarative model ui=f(state). So I'm trying something that I'm calling "imperative JSX." Instead of treating JSX as the source of truth for your UI, it essentially becomes a query interface for DOM manipulation. I first had the idea for it a few months ago, and only began writing it in earnest last week, so it's extremely early and nowhere near production-ready. Still, I'd…
2024 · npmjs.com · its alternatives →
- 23AM
I made an open source, MIT license Typescript library based on some of the latest research that generates prompt injection attacks. It is a super minimal/lightweight and designed to be super easy to use. Keen to hear your thoughts and please be responsible and only pen test systems where you have permission to pen test!
2025 · prompt-injector.blueprintlab.io · its alternatives →
- 24
A easy (and fast) typescript validation library/macro. Automatically generate validation functions for Typescript types. - vedantroy/typecheck.macro
2020 · github.com · its alternatives →
Also compare
- ScrapScript – A tiny functional language for sharable software alternatives
- TypeScript 6.0 alternatives
- Zero-codegen, no-compile TypeScript type inference from Protobufs alternatives
- Ezno, a TypeScript checker written in Rust, is now open source alternatives
- Crust – A CLI framework for TypeScript and Bun alternatives
- TypeScript as a proof assistant for intuitionistic propositional logic alternatives
Ranked by how close each launch is in meaning, then by votes. Prices were read from each product’s own site when checked and can change. Refine with your own description →