diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..6665ec2
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,47 @@
+# 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]
+
+## [0.1.0] - 2026-05-30
+
+### Added
+
+- **FrankenPHP runtime** — base image migrated from `php-cli` to FrankenPHP Alpine for better performance and built-in web server support
+- **FrankenPHP worker mode** — Symfony worker script (`public/worker.php`) with request reuse and graceful reload
+- **Caddy configuration** — `docker/frankenphp/Caddyfile` and `Caddyfile.dev` for production and development setups
+- **Provider health probes** — `ProviderInterface` extended with `ping()` and `probe()` methods; `ProbeTrait` provides the shared implementation
+- **Per-provider status on `/health`** — the health endpoint now reports `ok`, `degraded`, or `down` for each configured provider (GitHub, GitLab, Gitea), along with an error code and latency
+- **Supporting value objects** — `ProviderStatus`, `ProviderStatusType`, `ProviderErrorCode`, and `ProviderHealthChecker` service
+- **`ContributionAggregator` service** — contribution merging logic extracted from `GraphController` into a dedicated, testable service
+
+### Fixed
+
+- Optional environment variables (`GITLAB_URL`, `ALLOWED_HOSTS`, etc.) now have explicit empty default values in `docker-compose.yml`, preventing Docker Compose warnings on startup
+
+### Changed
+
+- `SvgRenderer` is now `final` and declares `strict_types=1`
+
+### Tests
+
+- Unit tests added for `ProbeTrait`, `ProviderHealthChecker`, `ProviderStatus`, `ContributionAggregator`, and all three provider probes (`GitHubProvider`, `GitLabProvider`, `GiteaProvider`)
+- `SvgRendererTest` refactored to follow project PHPUnit conventions (`#[Test]` attribute, `it_` prefix, Arrange/Act/Assert structure)
+
+## [0.0.1] - 2025-01-01
+
+### Added
+
+- Initial release — GitHub, GitLab, and Gitea contribution graph as a self-hosted SVG endpoint
+- Light and dark theme support
+- Filesystem cache with 1-hour TTL
+- Docker multi-stage build (`base → deps → build → final`)
+- Basic `/health` endpoint
+
+[Unreleased]: https://github.com/ArthurErlich/git-contribution-graph/compare/0.1.0...HEAD
+[0.1.0]: https://github.com/ArthurErlich/git-contribution-graph/compare/0.0.1...0.1.0
+[0.0.1]: https://github.com/ArthurErlich/git-contribution-graph/releases/tag/0.0.1