Open Source Haskell Software
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Haskell Software
Browse free open source Haskell Software and projects below. Use the toggles on the left to filter open source Haskell Software by OS, license, language, programming language, and project status.
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Apify is a full-stack web scraping and automation platform helping anyone get value from the web.Actors are serverless cloud programs that extract data, automate web tasks, and run AI agents. Developers build them using JavaScript, Python, or Crawlee, Apify's open-source library. Build once, publish to Store, and earn when others use it. Thousands of developers do this - Apify handles infrastructure, billing, and monthly payouts.
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The CRM you will want to use every dayAct! Premium is perfect for small and midsize businesses looking to market better, sell more, and create customers for life. With unparalleled flexibility and freedom of choice, Act! Premium accommodates the unique ways you do business. Whether it’s customizations to fit your specific business or industry processes or your preferences for deployment and access, the possibilities with Act! Premium are limitless.
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Pandoc
The universal markup converter
Pandoc is a universal document converter able to convert files from a multitude of markup formats into another. With Pandoc, you have a swiss-army knife of a converter, able to convert practically any markup format into any other. Pandoc contains a Haskell library for conversions as well as a command-line tool that uses this library. It can convert to and from just about anything-- lightweight markup formats, HTML formats, documentation formats, ebooks, TeX formats, word processor formats and so much more. It understands several useful markdown syntax extensions, such as document metadata, footnotes, tables, and more. If you want strict markdown compatibility however, these extensions can be turned off. Pandoc is no doubt powerful and customizable, but it is important to note that its intermediate representation of a document is less expressive than many of the formats, so it may not produce perfect conversions every time. -
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SimpleX
The first messaging platform operating without user identifiers
Other apps have user IDs: Signal, Matrix, Session, Briar, Jami, Cwtch, etc. SimpleX does not, not even random numbers. This radically improves your privacy. The video shows how you connect to your friend via their 1-time QR-code, in person or via a video link. You can also connect by sharing an invitation link. Temporary anonymous pairwise identifiers SimpleX uses temporary anonymous pairwise addresses and credentials for each user contact or group member. It allows to deliver messages without user profile identifiers, providing better meta-data privacy than alternatives. Many communication platforms are vulnerable to MITM attacks by servers or network providers. To prevent it SimpleX apps pass one-time keys out-of-band when you share an address as a link or a QR code. Double-ratchet protocol. OTR messaging with perfect forward secrecy and break-in recovery. NaCL cryptobox in each queue to prevent traffic correlation between message queues if TLS is compromised. -
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Echidna
Ethereum smart contract fuzzer
Echidna is a weird creature that eats bugs and is highly electrosensitive (with apologies to Jacob Stanley) More seriously, Echidna is a Haskell program designed for fuzzing/property-based testing of Ethereum smarts contracts. It uses sophisticated grammar-based fuzzing campaigns based on a contract ABI to falsify user-defined predicates or Solidity assertions. We designed Echidna with modularity in mind, so it can be easily extended to include new mutations or test specific contracts in specific cases. Optional corpus collection, mutation and coverage guidance to find deeper bugs. Powered by Slither to extract useful information before the fuzzing campaign. Source code integration to identify which lines are covered after the fuzzing campaign. Curses-based retro UI, text-only or JSON output. -
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FreeArc combines best 7-zip and RAR features: auto-selected LZMA/PPMD/Multimedia compression, 1gb dictionary, exe/dict/delta data filters, updatable solid archives, SFXes, recovery record, AES+Twofish+Serpent encryption, Linux support and much more...
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dhall-haskell
Maintainable configuration files
Maintainable configuration files. Navigate to each package's directory for their respective READMEs. You can download pre-built binaries for Windows, OS X and Linux on the release page. You can then click the "Help" button in the bottom right corner, which will show you a nix-env command that you can run to install the prebuilt executable. You will probably want to use the shared caches hosted at cache.dhall-lang.org and dhall.cachix.org when doing Nix development. This is not required, but this will save you a lot of time so that you don't have to build as many dependencies from scratch the first time. If you prefer installing the binaries locally in a nix shell environment instead, just run nix-shell in the top-level directory. This option provides additional flexibility with respect to overriding some of the default parameters (e.g. the compiler version), which makes it particularly useful for developers. -
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FOSSA CLI
Fast, portable and reliable dependency analysis for any codebase
FOSSA CLI is a command-line tool that scans your codebase to identify open-source dependencies and their associated licenses and vulnerabilities. It integrates into CI/CD pipelines to provide automated compliance checks, license audits, and security analysis. Designed for enterprise software teams, FOSSA CLI helps enforce open-source policies at scale and provides accurate, automated insights into third-party software usage through deep analysis of transitive dependencies and ecosystem-specific configurations. -
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ShellCheck
A static analysis tool for shell scripts
ShellCheck is a GPLv3 tool that provides warnings and possible suggestions for bash/sh shell scripts. ShellCheck finds bugs in your shell scripts. You can cabal, apt, dnf, pkg or brew install it locally right now. ShellCheck highlights and clarifies typical beginner's syntax mistakes and issues that cause a shell to give a cryptic error message. It shows typical intermediate level semantic problems that cause a shell to behave in a abnormally and counter-intuitively. It can also discover ssubtle caveats, corner cases and pitfalls that may cause an user's working script to fail under probable future circumstances. ShellCheck.net is always synchronized to the latest git version, and is the simplest way to give ShellCheck a go. -
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Extism
The Universal Plug-in System. Extend anything with WebAssembly
Extism is a plug-in system for everyone. We've carefully designed it to be flexible, fitting into codebases of all shapes and sizes, but opinionated enough so that things Just Work™ the way they should. Extism's goal is to make all software programmable. You can use Extism in your codebase, regardless of the programming language. We support several environments through our official Host SDKs, and are adding more language support all the time. A plug-in system is software that enables your users or customers to add some logic into certain points in your application. You decide where this logic runs, and your users decide what the plug-in does. Many engineering teams face an ever-growing list of feature requests, often exceeding their bandwidth several times over. How can you ever keep up? Making your product extensible by its end-users is a great way to move some of those features outside the core, and empower customers to make your software more useful for them. -
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pandoc-crossref filter
Pandoc filter for cross-references
pandoc-crossref is a pandoc filter for numbering figures, equations, tables and cross-references to them. The input file (like demo.md) can be converted into HTML, LaTeX, PDF, Markdown or other formats. Optionally, you can use cleveref for LaTeX/PDF output, e.g. cleveref PDF, cleveref LaTeX, and listings package, e.g. listings PDF, listings LaTeX. This package tries to use LaTeX labels and references if output type is LaTeX. It also tries to supplement rudimentary LaTeX configuration that should mimic metadata configuration by setting header-includes variable. The easiest option to get pandoc-crossref on Windows, macOS, or Linux, is to download pre-built executables available at the releases page. Bear in mind that those are a product of automated build scripts, and as such, provided as-is, with zero guarantees. Feel free to open issues if those don't work though, I'll try to do what I can. -
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PostgREST
REST API for any Postgres database
PostgREST is a standalone web server that turns your PostgreSQL database directly into a RESTful API. The structural constraints and permissions in the database determine the API endpoints and operations. Using PostgREST is an alternative to manual CRUD programming. Custom API servers suffer problems. Writing business logic often duplicates, ignores or hobbles database structure. Object-relational mapping is a leaky abstraction leading to slow imperative code. The PostgREST philosophy establishes a single declarative source of truth: the data itself. It’s easier to ask PostgreSQL to join data for you and let its query planner figure out the details than to loop through rows yourself. It’s easier to assign permissions to db objects than to add guards in controllers. (This is especially true for cascading permissions in data dependencies.) It’s easier to set constraints than to litter code with sanity checks. -
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Matterhorn
A feature-rich Unix terminal client for the Mattermost chat system
Matterhorn is a terminal client for the Mattermost chat system. We provide pre-built binary releases for some platforms. Please see the release list to download a binary release for your platform that matches your server version. When you run Matterhorn you'll be prompted for your server URL and credentials. To connect, just paste your web client's Mattermost URL into the Server URL box and enter your credentials. See the Matterhorn User Guide on the details for providing each kind of supported credentials. For most of our binary releases, no additional packages need to be installed; they should just work out of the box. But here are some additional requirements that may apply for your platform. Matterhorn version strings will be of the form ABBCC.X.Y where ABBCC corresponds to the lowest Mattermost server version expected to be supported by the release. For example, if a release supports Mattermost server version 1.2.3, the ABBCC portion of the matterhorn version will be 10203. -
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tetris
A terminal interface for Tetris
A terminal interface for Tetris. Installation on MacOS and Linux is outlined below. Windows support is questionable, but you can try to install from source. The default game is run by simply executing the tetris command. If the unicode characters look a bit wonky in your terminal, you can also run. People seem to have varying levels of success with the linux binary. Please note that it is compiled dynamically and hence should not be expected to work on most distros. This code is built on top of brick which makes building terminal user interfaces very accessible. -
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Wasp
A programming language that understands what a web app is
Wasp (Web Application Specification Language) is a declarative DSL (domain-specific language) for developing, building and deploying modern full-stack web apps with less code. Concepts such as app, page, user, login, frontend, production, etc. are baked into the language, bringing a new level of expressiveness and allowing you to get more work done with fewer lines of code. While describing high-level features with Wasp, you still write the rest of your logic in your favorite technologies (currently React, NodeJS, Prisma). Wasp is in alpha and is therefore likely to change a lot, have bugs and miss important features. Due to its expressiveness, you can create and deploy a production-ready web app from scratch with very few lines of concise, consistent, declarative code. When you need more control than Wasp offers, you can write code in existing technologies such as js/html/css/... and combine it with Wasp code! -
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koka
Koka language compiler and interpreter
Koka is a strongly typed functional-style language with effect types and handlers. The core of Koka consists of a small set of well-studied language features, like first-class functions, a polymorphic type- and effect system, algebraic data types, and effect handlers. Each of these is composable and avoid the addition of “special” extensions by being as general as possible. Koka tracks the (side) effects of every function in its type, where pure and effectful computations are distinguished. The precise effect typing gives Koka rock-solid semantics backed by well-studied category theory, which makes Koka particularly easy to reason about for both humans and compilers. Effect handlers let you define advanced control abstractions, like exceptions, async/await, or probabilistic programs, as a user library in a typed and composable way. Perceus is an advanced compilation method for reference counting. -
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Cardano Node
The core component that is used to participate in a Cardano
Cardano Node is the core software that powers the Cardano blockchain, a decentralized, proof-of-stake platform for smart contracts and digital assets. Developed in Haskell, the node allows participation in Cardano’s network by validating transactions, producing blocks, and maintaining the ledger. It supports Shelley, Goguen, Basho, and other phases of Cardano’s roadmap, and plays a crucial role in network security and consensus. The node is configurable for different use cases, including running full nodes, relay nodes, or stake pool operators. -
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Cryptol
Cryptol: The Language of Cryptography
Cryptol is a domain-specific language (DSL) for specifying and verifying cryptographic algorithms. Developed by Galois, Cryptol provides a high-level mathematical syntax for describing cryptographic primitives and enables formal verification of algorithm properties. It is used in academic, research, and defense sectors to validate correctness and security through symbolic execution and model checking, ensuring critical cryptographic code is free of design flaws. -
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Nix Output Monitor
Pipe your nix-build output through the nix-output-monitor
nix-output-monitor (also known as nom) is a workflow tool that enhances the readability and usability of nix-build output by providing pretty, parsed summaries and highlighting important events during Nix builds. This was an experiment to write something fun and useful in Haskell, which proved to be useful to quite a lot of people. By now, nom is quite fully featured with support for nix v1 commands (e.g. nix-build) and nix v2 commands (e.g. nix build). At this point it seems like I will maintain nom until better UX options for nix arrive. Every entry in the nom tree stands for one derivation. No build will be printed twice in the tree, it will only be shown for the lowermost dependency. Use the colors from above to read the summary. -
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Obelisk
Functional reactive web and mobile applications, with batteries
Functional reactive web and mobile applications, with batteries included. Obelisk's goal is to represent a cohesive, highly-curated set of choices that Obsidian Systems has made for building these types of applications in a way that is extremely fast but does not compromise on production readiness. Obelisk allows you to build high-quality web and mobile applications very quickly using Reflex. In minutes you can go from an empty directory to an interactive application that works on web, iOS, and Android, all sharing the same Haskell codebase! Obelisk's development environment also enables extremely rapid development and feedback. You can take advantage of Haskell's type system across the frontend and backend boundary. This means changes to your backend that would break your frontend are immediately detected during development and vice versa. Obelisk uses Haskell's compiler to give you a complete "TODO list" of what needs to be updated. -
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Plutus
The Plutus language implementation and tools
Plutus is the smart contract development framework for the Cardano blockchain, created using Haskell. It provides the core infrastructure for writing, testing, and deploying secure, deterministic smart contracts on the Cardano platform. Plutus includes a custom functional language (Plutus Core), a higher-level embedded DSL (Plutus Tx) for writing contracts in Haskell, and an off-chain infrastructure for managing interactions. It ensures strong correctness guarantees through formal verification and functional programming paradigms. -
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SimpleXMQ
A reference implementation of the SimpleX Messaging Protocol
A reference implementation of the SimpleX Messaging Protocol for simplex queues over public networks. SimpleXMQ is a message broker for managing message queues and sending messages over a public network. It consists of an SMP server, SMP client library, and SMP agent that implements SMP protocol for client-server communication and SMP agent protocol to manage duplex connections via simplex queues on multiple SMP servers. SMP protocol is inspired by Redis serialization protocol, but it is much simpler - it currently has only 10 client commands and 8 server responses. -
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nixfmt
The official formatter for Nix code
nixfmt is a code formatter for the Nix expression language, aiming to provide consistent and idiomatic formatting for Nix files. It is written in Haskell and designed to be fast, predictable, and fully automatic with zero configuration. nixfmt helps Nix developers maintain readability and code consistency across large codebases, facilitating collaboration and version control workflows. -
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Carp
A functional, systems programming language with linear types
Carp is a statically typed, functional programming language designed for real-time and systems programming. It features a Lisp-like syntax, strong compile-time checks, and linear type semantics that ensure memory safety without a garbage collector. Carp targets C as its backend, generating performant and predictable native code while offering functional abstractions and interactive development via REPL. -
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Gifcurry
The open-source, Haskell-built video editor for GIF makers
The open-source, Haskell-built video editor for GIF makers. Gifcurry is the open-source video editor for GIF makers. It's built with Haskell and works on Linux, Mac, and most likely Windows. There is both a graphical and command line interface. Gifcurry edits your GIFs or videos and turns them into videos or GIFs. You can crop, trim, seek, add text, pick a font, alter the duration, change the size, set the FPS, tweak the color count, enable dithering, import subtitles, and save your creation as either a GIF or video. Before you download Gifcurry, make sure your machine has GTK+, GStreamer, FFmpeg, and ImageMagick. Linux users can download the AppImage or the prebuilt binaries. If you'd rather install it, you can do so via pacman (Arch) or snap. If you're really courageous, you can build it from source. -
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Kmonad
An advanced keyboard manager
KMonad is a cross-platform, advanced keyboard remapping tool written in Haskell. It provides low-level key control, supporting layers, tap-hold combos, multi-tap, macros, and more—even for keyboards without firmware-level customization. -
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Stack
The Haskell Tool Stack
Stack is a cross-platform build tool for Haskell projects that simplifies dependency management, project setup, and reproducible builds. It provides curated package sets (Stackage), isolated project environments, and consistent tooling for compiling and testing Haskell applications. Stack streamlines workflows for developers by automating many parts of the Haskell toolchain, making it easier to get started and maintain complex codebases. It supports integration with GHC (Glasgow Haskell Compiler) and Hackage.
