A self-hosted photo library focused on privacy, data durability, and ease of use.
Replycant is a simple photo library based on proven technologies. It uses Git with LFS for storage of metadata and binary objects, mTLS for client authentication, Age for key encryption and AES-GCM for metadata/object encryption.
- Private by design — photos and metadata are encrypted before upload; the server stores only ciphertext
- Based on proven technologies — uses Git and Git LFS, with metadata structured as YAML
- Zero-config hosting — start with Docker Compose and connect by scanning a QR code
- Easy to back up — copy or mirror your complete library using standard Git and filesystem tools
- Device-centric auth — each device authenticates with its own mTLS certificate; no passwords or central user database
Part of Replycant is also an open source iOS app which is published on the app store.
1. Start the server
Download docker-compose.yaml
from the latest GitHub Release, and then start it:
curl -fsSL -o docker-compose.yaml \
https://github.com/mr-andreas/replycant/releases/latest/download/docker-compose.yaml
docker compose upThis will use the directory where you have placed docker-compose.yaml for both metadata and binary storage, which is usually fine. If you wish to select another directory or change the published ports, create a .env, then bring the stack up:
cat > .env << EOF
REPLYCANT_DATA_DIR=/var/lib/replycant/data
REPLYCANT_LFS_DIR=/var/lib/replycant/lfs
REPLYCANT_GIT_PORT=8443
REPLYCANT_CA_PORT=8080
EOFThe Git server listens on port 8443 (HTTPS) by default, and the
discovery server on port 8080. On the LAN the stack advertises as
<hostname>.local. Set REPLYCANT_HOSTNAME to override that name, and
REPLYCANT_GIT_PORT and REPLYCANT_CA_PORT when those defaults are
already in use. Already-linked devices need re-onboarding after a
hostname or port change.
Note: On Mac and Windows, Docker runs in a VM, so hostname auto-detection does not work. Set the name this computer uses on the LAN before starting the stack:
echo REPLYCANT_HOSTNAME=$(hostname) >> .env docker compose up
2. Install the iOS client
3. Link a device
Using your computer, open the URL that you host the server on. Usually, this is http://localhost:8080 (or http://localhost:$REPLYCANT_CA_PORT if you changed the CA port). Start the iOS app and scan the QR code.
Replycant encrypts photos, videos, and metadata on the client before uploading them. The server stores only opaque ciphertext, so compromising the server is not enough to expose your library. Only authorized devices hold the keys needed to decrypt it.
Replycant builds on Git for versioned metadata and Git LFS for photos and videos. Metadata is structured as YAML manifests, giving the library an inspectable data model and a complete history instead of tying it to an opaque hosted database.
On a typical Linux host, download the Docker Compose file and run
docker compose up. Replycant supplies sensible defaults for storage, ports,
and local-network discovery. Open the discovery page and scan its QR code to
connect the iOS app.
The Git repository can be copied, moved, or mirrored with established tools.
Git records the metadata history, while Git LFS storage holds encrypted media.
Backing up both gives you an independent copy of the complete library. Want an
extra backup somewhere? Simply create one using git-replycant clone and do
regular git pull to receive updates.
Each device generates its own key pair and authenticates with an mTLS client certificate. Private keys remain on the device, while authorized public keys are committed to the library repository, making access control auditable through Git history. New devices are authorized by an existing device using QR codes—without passwords, user accounts, or a central identity database.