JetBrains IDE Plugin

Flexible Haskell: Haskell IDE Plugin for JetBrains

Write Haskell with HLS completion and diagnostics, run a GHCi REPL and debug, all inside your JetBrains IDE.

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4.6 3 ratings · JetBrains Marketplace

JetBrains IDEs: IntelliJ IDEA · PyCharm · WebStorm · PhpStorm · and other JetBrains IDEs

HLS: Completion, diagnostics and hover docs
GHCi: REPL and debugger in the IDE
100: Live templates

What Developers Are Saying

★★★★★

“A very strong start. Extremely responsible and forward support.”

Andrei Dziahel — JetBrains Marketplace

★★★★★

“Works well already, and the developer is very responsive for feature requests. In my opinion this is clearly the go-to Haskell plugin now.”

Christopher Cowell — JetBrains Marketplace

Debug with the GHCi Debugger

Set line breakpoints in Haskell code and step through it in the IDE Debug tool window. The debugger works over Stack, Cabal and runghc.

Line breakpoints in the editor gutter
Variables shown in the Debug tool window
Integrated GHCi REPL in a tool window, with clickable GHC stack traces

Debug tool window stopped on a breakpoint in a Haskell file, with local variables listed and the editor showing the breakpoint line

Run Configurations for Stack, Cabal and runghc

Run any .hs file from a run configuration. Choose the run mode, or let the plugin pick it.

Run modes: auto, runghc, stack run and cabal run
An auto-producer creates a run configuration for any .hs file
A run gutter marker sits on main

Run/Debug Configurations dialog for a Haskell run with the run mode dropdown open and the entries auto, runghc, stack run and cabal run

GHC, HLS and Cabal Settings

Point the plugin at your toolchain and switch on the Haskell Language Server.

HLS gives completion, diagnostics, hover docs, inlay type hints and code lenses
Set GHC, HLS, Stack and Cabal paths in one settings page, or download a GHC SDK with GHCup from Tools > Haskell
Choose ormolu, fourmolu or stylish-haskell as the formatter, with optional format on save
Edit .cabal and cabal.project files with completion and cabal-fmt formatting

Haskell settings page showing the GHC path and version, empty HLS, Stack and Cabal path fields, auto-start options and the formatting provider ormolu

Start a Haskell Project

Create a project from the New Project wizard and add a GHC SDK from the project settings.

A Haskell entry in the New Project wizard scaffolds a minimal src/Main.hs
File templates for Haskell Module, Haskell Script and Haskell Test
100 live templates: type an abbreviation such as fn, dt or inst and press Tab

New Project dialog with Haskell selected in the generators list and name and location fields

Inspections and Quick Fixes

The IDE flags common Haskell problems while you type.

16 inspections, including missing type signatures, unused imports and possibly incomplete pattern matches
6 intention actions, such as add a missing import, add a type annotation and add a LANGUAGE pragma
Import optimizer with Ctrl+Alt+O

Problems tool window listing warnings that top-level functions are missing a type signature

AI Assistant in the IDE

An optional AI chat tool window for your Haskell project. One switch in the settings turns it off.

Works with Claude Code, Codex, Cursor, Windsurf, Antigravity, Aider or your own Anthropic, OpenAI, Gemini or Ollama key
An MCP server with 32 IDE tools, installed into your agent CLI in one click