JetBrains AI / Junie vs Kiro

JetBrains AI / Junie vs KiroComparisonUpdated 2026-03-16

SUMMARY

JetBrains AI / Junie (IDE) uses markdown configuration while Kiro (IDE) uses markdown. They differ on 3 of 11 compared features. Both tools provide AI-assisted development but take different approaches to project configuration.

FEATURE COMPARISON

Feature	JetBrains AI / Junie	Kiro	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	✓	✓
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	Kiro
Settings / configuration	.noai	.kiro/hooks/*.kiro.hook

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

Kiro

.kiro/steering/*.md

markdown

---
inclusion: always
---

# Project Standards

## Stack
- TypeScript 5.x with Node.js 22
- AWS CDK v2 for infrastructure
- DynamoDB for data, S3 for assets

## Conventions
- Use ESM imports, not CommonJS
- Lambda handlers export a named `handler` function
- Use middy middleware for cross-cutting concerns
- All API responses follow JSON:API format

## Testing
- Unit tests with vitest
- Integration tests with aws-testing-library
- E2E tests use deployed staging environment

KEY DIFFERENCES

1. Hierarchy support

JetBrains AI / Junie: Not supported. Kiro: Supported.

2. Global config

JetBrains AI / Junie: Not supported. Kiro: Supported.

3. Ignore file

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

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 Kiro, configure .kiro/steering/*.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