JetBrains AI / Junie vs Replit

JetBrains AI / Junie vs ReplitComparisonUpdated 2026-03-16

SUMMARY

JetBrains AI / Junie (IDE) uses markdown configuration while Replit (Platform) uses markdown. They differ on 2 of 11 compared features. Both tools provide AI-assisted development but take different approaches to project configuration.

FEATURE COMPARISON

Feature	JetBrains AI / Junie	Replit	Notes
Config format	markdown	markdown
Hierarchy support	✗	✗	Whether config files can be placed at multiple directory levels
Global config	✗	✗	User-wide configuration outside any project
Project config	✓	✓
Subdirectory scoping	✗	✗	Config files in subdirectories that apply only to that subtree
File inclusion / imports	✗	✗	Ability to include or reference other files from config
Ignore file	.aiignore	✗
IDE integration	✓	Platform
Schema / structure	Free-form (Markdown)	Free-form (Markdown)	Whether config uses structured schema or free-form content
Git committed	✓	✓	Whether primary config files are intended to be version-controlled
Encoding	UTF-8	UTF-8

FILE MAPPING

Purpose	JetBrains AI / Junie	Replit
Settings / configuration	.noai	.replit

SIDE-BY-SIDE CODE SAMPLES

JetBrains AI / Junie

.aiassistant/rules/*.md

markdown

# Kotlin Conventions

## Language Features
- Use Kotlin 2.x with coroutines for async work
- Prefer data classes for DTOs and value objects
- Use sealed classes/interfaces for domain errors
- Extension functions over utility classes

## Spring Boot
- Constructor injection (no field injection)
- Use @ConfigurationProperties over @Value
- Prefer WebFlux for reactive endpoints
- Use Spring Security with method-level security

## Testing
- JUnit 5 with Kotest assertions
- MockK for mocking (not Mockito)
- Testcontainers for integration tests
- Use @Nested for test organization

Replit

replit.md

markdown

# My Project

## Overview
This is a Next.js e-commerce storefront with Stripe payments, NextAuth
authentication, and a PostgreSQL database via Prisma ORM.

## Tech Stack
- Framework: Next.js 14 (App Router, server components by default)
- Database: PostgreSQL with Prisma ORM
- Auth: NextAuth.js with GitHub and Google providers
- Payments: Stripe Checkout and webhooks
- Styling: Tailwind CSS with shadcn/ui components

## Development Phase
Currently building the product catalog and cart system. Authentication
and payment flows are complete. Next up: order history and admin dashboard.

## Code Style
- TypeScript strict mode enabled
- Prefer server components; use "use client" only when needed
- Use server actions for mutations (app/actions/)
- Validate all inputs with Zod schemas

## Commands
- `npm run dev` — start development server on port 3000
- `npm run build` — production build
- `npm run db:push` — push Prisma schema to database
- `npm run db:seed` — seed database with sample data
- `npm test` — run Jest test suite

## External Resources
- Design system: https://ui.shadcn.com
- API docs: Stripe API at https://stripe.com/docs/api

KEY DIFFERENCES

1. Ignore file

JetBrains AI / Junie: .aiignore. Replit: Not supported.

2. IDE integration

JetBrains AI / Junie: Supported. Replit: Platform.

WHICH SHOULD I USE?

Recommendation

Choose based on your IDE/CLI preference. If you use JetBrains AI / Junie, configure .aiassistant/rules/*.md. If you use Replit, configure replit.md. Many projects include config files for multiple tools so each team member can use their preferred editor.

PORTABILITY TIP

sync-instructions.sh

bash

# Maintain a single source of truth:
cp AI-INSTRUCTIONS.md CLAUDE.md
cp AI-INSTRUCTIONS.md .cursorrules
cp AI-INSTRUCTIONS.md AGENTS.md