diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..32f2077
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,45 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+### Added
+
+- **Project Management** - Create and manage projects with dashboard view
+- **Git Repository Management** - Bare repository initialization and mirror cloning with smart URL parsing
+- **Repository Workspace** - File browser with syntax highlighting, branch switching, and file editing
+- **Git History Visualization** - Commit history with graph visualization and diff viewing
+- **Git Control** - Branch management, commit, fetch/pull/push, merge operations
+- **File Editor** - Syntax highlighting for 50+ languages with edit/commit workflow
+- **Smart Git URL Parsing** - Automatic detection and correction of browser URLs to git clone URLs
+- **OAuth2 Authentication** - Session-based authentication via Authentik with simplified flow
+- **User Profile** - Profile management with avatar upload
+- **User Settings** - Theme selection, git identity, and preference management
+- **SSH Key Management** - Ed25519 key generation with secure storage
+- **Tool Types** - Built-in development tools (code-server, jupyter-notebook) with custom type support
+- **Comprehensive Documentation** - Architecture, API, deployment, and development guides
+
+### Changed
+
+- Simplified authentication from JWT to session-based cookies
+- Restructured test infrastructure with unit/integration/system separation
+- Improved Docker deployment with Traefik integration
+
+### Fixed
+
+- Database migration chain errors
+- Cross-origin cookie handling for OAuth flow
+- Nginx permission issues in container
+
+## [0.1.0] - 2026-05-19
+
+### Added
+
+- Initial release with core project and repository management
+- OAuth2 authentication with Authentik
+- Basic file browsing and git history viewing
+- Development tool type definitions