Postizer

Postizer is a Go-based, server-rendered blog system with Markdown, KaTeX math, pseudo-static URLs, and a black-and-white information-dense Times New Roman newspaper theme.

Run

go run ./cmd/postizer

Open:

• Public site: http://localhost:8080/
• Example post: http://localhost:8080/posts/welcome
• Example page: http://localhost:8080/pages/about
• Admin editor: http://localhost:8080/admin
• Media library: http://localhost:8080/admin/media

Docker

Build and run with Docker Compose:

cp .env.example .env
# Edit .env and set a strong POSTIZER_ADMIN_PASSWORD and POSTIZER_SESSION_SECRET.
docker compose up -d --build

Open http://localhost:8080/. Compose stores runtime data in named volumes:

• postizer-runtime: the WordPress-style writable application runtime copied from the image on first start.
• postizer-content: posts, pages, settings, session secret, and admin credentials.
• postizer-media: uploaded media files and the media index.

The Docker image seeds /app/runtime/current from /usr/src/postizer when the runtime volume is empty, then starts Postizer from that writable runtime path. This lets future in-app updates replace the runtime files without depending on the Docker image tag. When Admin -> Settings -> Auto Update is enabled, the Docker image checks POSTIZER_REPO_URL for the newest GitHub Release with a vX.X.X tag, downloads the matching postizer-vX.X.X-linux-<arch>.tar.gz, verifies SHA256SUMS, switches /app/runtime/current, and exits so Docker can restart into the new build.

Resource Marketplace

Admin -> Resource Marketplace is backed by marketplace/packs/index.json. The default source is the official GitHub raw index with the packaged local index as a fallback. Set POSTIZER_RESOURCE_MARKETPLACE_URL to point at another trusted index.

Marketplace entries install .zip bundle assets from GitHub Releases. Entries list the themes and plugins they contain, and use theme / plugin tags for the built-in admin filters. Postizer verifies the indexed SHA-256 digest, checks that the downloaded bundle ID matches the index entry, and requires the bundle source_url to match the listed GitHub repository.

For a direct Docker run:

docker build -t postizer:latest .
docker run -d --name postizer \
  -p 8080:8080 \
  -v postizer-runtime:/app/runtime \
  -v postizer-content:/app/content \
  -v postizer-media:/app/media \
  -e POSTIZER_ADMIN_USER=admin \
  -e POSTIZER_ADMIN_PASSWORD='change-this-password' \
  -e POSTIZER_SESSION_SECRET='change-this-long-random-secret' \
  -e POSTIZER_REPO_URL='https://github.com/WiDayn/Postizer.git' \
  -e POSTIZER_RELEASE_VERSION='latest' \
  postizer:latest

To publish the Docker image automatically, create these GitHub repository secrets:

• DOCKERHUB_USERNAME: your Docker Hub username or organization.
• DOCKERHUB_TOKEN: a Docker Hub access token with write access.

Then push a version tag:

git tag v0.1.2
git push origin v0.1.2

The release workflow publishes GitHub Release assets and pushes:

• DOCKERHUB_USERNAME/postizer:v0.1.2
• DOCKERHUB_USERNAME/postizer:latest

Linux Service Install

On a Linux host with systemd:

curl -fsSL https://raw.githubusercontent.com/WiDayn/Postizer/main/scripts/install-linux-service.sh | sudo bash -s -- \
  --service-name postizer \
  --port 8080 \
  --install-dir /opt/postizer \
  --env-file /etc/postizer/postizer.env \
  --bin-link /usr/local/bin/postizer \
  --update-service-name postizer-update \
  --update-timer-name postizer-update \
  --update-interval 15min

The installer downloads the latest GitHub Release asset matching the host architecture, verifies SHA256SUMS, installs the runtime into /opt/postizer, writes /etc/postizer/postizer.env, registers postizer.service, enables it, starts it, and registers postizer-update.timer plus postizer-update.path. If POSTIZER_ADMIN_PASSWORD is not set, the installer generates an initial admin password and prints it once. Automatic updates are off by default and can be enabled in Admin -> Settings -> Auto Update; the timer only upgrades when a newer GitHub Release tag matching vX.X.X is available, so ordinary commits are ignored. A manual update requested from the authenticated admin page writes a protected trigger file, which makes the path unit start the same root-owned updater immediately without granting the web process sudo access.

If you are already inside a cloned repository, you can also run:

bash scripts/install-linux-service.sh

Common options:

curl -fsSL https://raw.githubusercontent.com/WiDayn/Postizer/main/scripts/install-linux-service.sh | sudo env POSTIZER_ADMIN_PASSWORD='change-this-password' bash
curl -fsSL https://raw.githubusercontent.com/WiDayn/Postizer/main/scripts/install-linux-service.sh | sudo bash -s -- --addr 127.0.0.1:8080 --no-start
curl -fsSL https://raw.githubusercontent.com/WiDayn/Postizer/main/scripts/install-linux-service.sh | sudo bash -s -- --service-name postizer-blog2 --port 8081
curl -fsSL https://raw.githubusercontent.com/WiDayn/Postizer/main/scripts/install-linux-service.sh | sudo bash -s -- --release-version v1.2.3
bash scripts/install-linux-service.sh --binary ./postizer
bash scripts/install-linux-service.sh --skip-deps
bash scripts/install-linux-service.sh --build-from-source --source-dir /srv/postizer-src
bash scripts/install-linux-service.sh --no-update-timer

For multiple instances on one host, use a unique --service-name and port. Unless overridden, the installer derives isolated paths from the service name, such as /opt/postizer-blog2, /etc/postizer-blog2/postizer-blog2.env, /usr/local/bin/postizer-blog2, and postizer-blog2-update.timer. You can override the pieces individually with --install-dir, --bin-link, --env-dir, --env-file, --update-service-name, and --update-timer-name.

Installer options:

Option	Description
--install-dir PATH	Runtime directory. Defaults to /opt/<service-name>.
--release-version VERSION	GitHub Release version to install. Defaults to latest.
--repo-url URL	GitHub repository used for release assets. Defaults to https://github.com/WiDayn/Postizer.git.
--service-name NAME	systemd service name. Defaults to postizer.
--update-service-name NAME	systemd oneshot update service name. Defaults to <service-name>-update.
--update-timer-name NAME, --timer-name NAME	systemd update timer name. Defaults to <update-service-name>.
--update-interval N	Auto-update timer interval. Defaults to 15min.
--addr ADDR	POSTIZER_ADDR listen address, for example 127.0.0.1:8080.
--port PORT	Listen on :PORT; shorthand for --addr :PORT.
--user NAME	Linux service user. Defaults to postizer.
--group NAME	Linux service group. Defaults to the service user.
--bin-link PATH	Symlink path for the installed binary. Defaults to /usr/local/bin/<service-name>.
--env-dir PATH	Environment file directory. Defaults to /etc/<service-name>.
--env-file PATH	Environment file path. Defaults to <env-dir>/<service-name>.env.
--binary PATH	Install an existing binary instead of building from source.
--no-build	Use ./postizer from the source directory.
--build-from-source	Build from a Git checkout instead of using a release asset.
--source-dir PATH	Source checkout directory, only used with --build-from-source.
--go-cache-dir PATH	Go build/module cache root, only used with --build-from-source.
--no-git-pull, --skip-git-pull	Do not update an existing Git checkout before building from source.
--skip-deps	Do not install missing OS packages automatically.
--no-update-timer	Do not register the automatic update timer.
--no-enable	Do not enable the service at boot.
--no-start	Do not start or restart the service after installation.

Service commands:

sudo systemctl status postizer
sudo journalctl -u postizer -f
sudo systemctl restart postizer
sudo systemctl status postizer-update.timer

Default local admin login:

• Username: admin
• Password: postizer

Override for real use:

$env:POSTIZER_ADMIN_USER = "admin"
$env:POSTIZER_ADMIN_PASSWORD = "change-this-password"
$env:POSTIZER_SESSION_SECRET = "change-this-long-random-secret"
go run ./cmd/postizer

If POSTIZER_SESSION_SECRET is not set, Postizer creates content/.session_secret so local login sessions survive server restarts. The login form also has a "Remember me" option for a 30-day browser session.

Content

• Posts: content/posts/*.md
• Pages: content/pages/*.md
• Optional tag metadata: content/tags/*.md

Posts and pages use YAML-like front matter followed by Markdown.

Plugins

Postizer supports static resource plugins and gRPC process plugins. Static plugins can contain only translations, templates, or styles and do not need an executable. gRPC plugins declare a runtime.kind of grpc in their manifest; Postizer starts the plugin as a separate process and calls its PluginService over gRPC. Plugin admin UI is declared through manifest ui_entries pointing at static JSON files, so settings pages can render without starting the plugin process. Process plugins can import the public pkg/pluginrpc SDK and call the host HostService for generic operations such as job progress, media saves, post/page saves, content exports, and runtime reloads.

The WordPress importer and content exporter are kept as external example bundles under examples/bundles, not as part of the main application. Package a bundle and install it through /admin/plugins; installed user plugins live under content/bundles. The content exporter example creates a ZIP containing content/posts, content/pages, media/index.json, and all files under media/public.

Plugin manifests can declare compatibility requirements with requires.postizer and requires.host_services. Postizer checks those declarations during resource-pack installation and returns compatibility warnings for unsupported versions or RPC methods while still allowing the pack to be installed.

Media

Images are uploaded into media/public/{year}/{month}/. The admin editor supports pasting an image from the clipboard and inserts a numbered figure at the current cursor position:

\begin{figure}
![Image](/media/2026/05/hash.png)
\caption{Image}
\label{fig:post-1}
\end{figure}

Use \figref{fig:post-1} for a named figure reference.

POSTIZER_ADMIN_TOKEN can still be used for API automation with Authorization: Bearer ..., but browser admin access uses the login session.

Editor

The admin editor at /admin includes:

• Login session authentication.
• Dedicated admin shell with sidebar pages.
• Dashboard, Posts, Editor, Media, and Settings sections.
• Post library with draft/published state.
• Title, automatic URL path with numeric duplicate suffixes, date, updated date, tags, summary, draft, and TOC fields.
• Markdown toolbar.
• Edit, split, and preview modes.
• Server-rendered live preview using the same Markdown pipeline as public posts.
• Save draft, publish, and delete actions for files in content/posts/{title-slug}.md.
• Media upload, recent media thumbnails, click-to-insert, and paste-to-upload.
• Media library upload, rename, caption/alt editing, figure copying, and delete actions.
• Optional home image upload in Settings for the front page image band.

Frontend Method

Frontend work should start from the base component library in web/static/site.css, using ui-* primitives before adding page-specific classes. See docs/FRONTEND.md for the methodology and component inventory.