A plug-and-play Unraid Community Applications template for Claper — the open-source, self-hosted Mentimeter/Slido alternative. Wraps the official ghcr.io/claperco/claper image: run live polls, Q&A and quizzes alongside your slides, your audience joins from their own phone or laptop, no app install. Every option is exposed in the template form.

Maintained solo, in whatever spare time there is. Questions via the support thread, bugs, ideas and feature requests via GitHub issues. If it's useful to you, a coffee is always welcome.

Table of Contents

1. What is this?
2. Features
3. PostgreSQL setup (do this first)
4. Quick Start on Unraid
5. Configuration
6. Reverse proxy & HTTPS
7. Backup & restore
8. Updating
9. Troubleshooting
10. License
11. Support this project

1. What is this?

An Unraid Community Applications template for Claper (source). It deploys the official ghcr.io/claperco/claper image — an open-source (AGPL-3.0) tool for running live polls, Q&A and quizzes alongside a presentation. The audience joins from a link or QR code on their own device; no app to install, no account required to participate.

2. Features

• Live polls, quizzes and Q&A during a presentation, results update in real time
• Slide upload (PDF/PPTX/images) with a join link and QR code generated per event
• Self-hosted, AGPL-3.0 — your events and responses stay on your own server
• Optional self-registration for presenter accounts (toggle in the template)
• Multi-language UI (English, French, Spanish, Italian, German by default)
• Multi-arch upstream image — amd64 + arm64

3. PostgreSQL setup (do this first)

Claper needs a reachable PostgreSQL server and takes one combined connection string (DATABASE_URL), not separate host/user/password fields. Create a database and user first, for example via docker exec -it <postgres-container> psql -U postgres:

CREATE DATABASE claper;
CREATE USER claper WITH ENCRYPTED PASSWORD 'change-me';
GRANT ALL PRIVILEGES ON DATABASE claper TO claper;

Then build the Database URL field from those values:

postgres://claper:change-me@192.168.1.10:5432/claper

Migrations run automatically on container start — no manual step needed.

4. Quick Start on Unraid

1. Install from Community Applications, or add this template's URL directly: https://raw.githubusercontent.com/junkerderprovinz/unraid-apps/main/claper/claper.xml
2. Fill in Database URL (see section 3).
3. Set Secret Key Base — generate one on the Unraid console: openssl rand -base64 48.
4. Set Base URL to your server's real address or reverse-proxy domain.
5. Start the container, open the WebUI, log in with the seeded admin account admin@claper.co / claper — change that password immediately.

5. Configuration

Claper also supports SMTP/Postmark mail, OIDC login, and S3-compatible storage instead of the local Uploads path — none of these are exposed as template fields (advanced, rarely needed for a home install); set them as extra container variables if you need them. See Claper's own configuration docs for the full variable list.

6. Reverse proxy & HTTPS

Claper works fine on plain LAN HTTP. For access from outside your network, put it behind a reverse proxy with HTTPS and set Base URL to the public https:// address — this is what gets embedded in join links and QR codes shown to your audience.

7. Backup & restore

Back up two things: the Uploads volume (presentation files) and the PostgreSQL database (everything else — accounts, events, poll/quiz results). Restoring both together restores a working instance; restoring only one leaves uploads and database references out of sync.

8. Updating

Community Applications shows an update badge when a new image is available. Stop the container, pull the new :latest, start it again — migrations run automatically.

9. Troubleshooting

• Container won't start, log mentions SECRET_KEY_BASE — the field is empty or under 32 bytes. Generate a real one: openssl rand -base64 48.
• Container won't start, log mentions BASE_URL — the value must start with http:// or https:// (a bare hostname is rejected).
• Can't reach the database — check DATABASE_URL's host/port are reachable from this container (same Docker network or a routable IP), and that the database/user from section 3 actually exist.
• Forgot the admin password — reset it directly in Postgres, or drop and let it reseed on a fresh database (loses all data).

10. License

This template is MIT-licensed (see ../LICENSE). Claper itself is licensed AGPL-3.0 by ClaperCo — this is an independent, community-maintained Unraid packaging and is not affiliated with the Claper project.

11. Support this project

Questions? Check the support thread. Bugs, ideas or feature requests? Please open a GitHub issue.

This is a one-person project. I put a lot of time and effort into building and maintaining it, in whatever free time I have. If it's helped you, I'd genuinely appreciate the support: you're welcome to buy me a coffee.