Aider vs Devin | agentconfig.ing

Aider vs DevinComparisonUpdated 2026-03-16

SUMMARY

Aider (CLI) uses markdown configuration while Devin (Agent) uses markdown. They differ on 4 of 11 compared features. Both tools provide AI-assisted development but take different approaches to project configuration.

FEATURE COMPARISON

Feature	Aider	Devin	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	.aiderignore	✗
IDE integration	CLI	Agent
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	Aider	Devin
Settings / configuration	.aider.conf.yml	.devin/wiki.json
Project instructions	CONVENTIONS.md	AGENTS.md

SIDE-BY-SIDE CODE SAMPLES

Aider

CONVENTIONS.md

markdown

# Project Conventions

## Language
- TypeScript strict mode, no `any` types
- Prefer const over let, never use var
- Use template literals over string concatenation

## Architecture
- Feature-based folder structure under src/features/
- Each feature exports through an index.ts barrel file
- Shared utilities go in src/lib/

## Error Handling
- Use Result<T, E> pattern for expected failures
- Throw only for programmer errors
- Always log errors with structured context

## Testing
- Colocate tests next to source files (*.test.ts)
- Use factories for test data, not fixtures
- Integration tests in __tests__/ directories

Devin

AGENTS.md

markdown

# Agent Instructions

## Setup
- Python 3.12 with uv package manager
- PostgreSQL 16 and Redis 7
- Run: uv sync && uv run alembic upgrade head

## Commands
- Dev server: uv run uvicorn app.main:app --reload
- Tests: uv run pytest -x --tb=short
- Lint: uv run ruff check . && uv run mypy .
- Format: uv run ruff format .

## Code Style
- FastAPI with async endpoints
- Pydantic v2 for all schemas
- SQLAlchemy 2.0 async sessions
- Repository pattern for data access

## PR Guidelines
- Keep PRs focused on a single issue
- Add tests for new functionality
- Run the full test suite before submitting

KEY DIFFERENCES

1. Hierarchy support

Aider: Not supported. Devin: Supported.

2. Global config

Aider: Supported. Devin: Not supported.

3. Ignore file

Aider: .aiderignore. Devin: Not supported.

4. IDE integration

Aider: CLI. Devin: Agent.

WHICH SHOULD I USE?

Recommendation

Choose based on your IDE/CLI preference. If you use Aider, configure .aider.conf.yml. If you use Devin, configure AGENTS.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