---
title: "Deploy Remark42"
description: "Comment engine you embed on any web page with one script tag"
category: "Blogs"
url: https://railway.com/deploy/remark42-comments
---

# Deploy Remark42

Comment engine you embed on any web page with one script tag

**[Deploy Remark42 on Railway](https://railway.com/template/remark42-comments)**

Machine-readable deploy manifest (JSON, validated by TemplateCI): https://railway.com/deploy/remark42-comments/manifest.json

- **Creator:** A3A
- **Category:** Blogs
- **Total deploys:** 1

## Template content

### mailpit https://cdn.jsdelivr.net/gh/homarr-labs/dashboard-icons/svg/mailpit.svg

- **Image:** axllent/mailpit:latest
- **Health check:** /livez
- **Public domain:** Yes

### remark42 https://cdn.jsdelivr.net/gh/umputun/remark42@v1.17.1/site/static/android-chrome-512x512.png

- **Image:** umputun/remark42:latest
- **Health check:** /ping
- **Public domain:** Yes

## Documentation

# Deploy and Host Remark42 on Railway

Remark42 is an open-source commenting engine, written in Go by Umputun, that you embed on any web page with a single script tag. It gives readers threaded discussions, markdown, voting and email or OAuth sign-in, and it gives you what hosted comment platforms never do: the comments themselves, in a file you own, with no third-party tracking scripts. Bloggers, documentation sites and static-site builders on Hugo, Astro or Next.js all end up here.

Self-host Remark42 on Railway and this template wires up the parts that usually take an afternoon. The `remark42` service runs `umputun/remark42:latest` behind a public HTTPS domain, keeping every comment, avatar, uploaded image and nightly backup on a volume at `/srv/var`. A second service, `mailpit`, provides SMTP on the private network so email sign-in links and notifications work the moment the deploy finishes, with a password-protected inbox for reading what was sent. Run Remark42 on Railway and the public URL, the signing secret, the trusted-proxy ranges and the mail wiring are already set.

![Remark42 and Mailpit services on Railway with their volumes](https://res.cloudinary.com/rroe4rtk/image/upload/f_auto,q_auto/v1789467067/remark42-architecture.webp)

## Getting Started with Remark42 on Railway

Open the `remark42` service's public URL and add `/web/` — that path serves a demo page with the widget pointed at your own instance, and it is the fastest way to confirm the deployment works. There is no admin account and no default password: click **Sign In**, choose **Email**, enter any username and address, and Remark42 mails a one-time token. Open the `mailpit` URL, sign in with the credentials in its `MP_UI_AUTH` variable, copy the token out of the message and paste it into the widget.

Now make yourself a moderator. Click your own name in the widget to expand your profile and copy the user id, which looks like `email_91dbc8cf…`. Put it in the `remark42` service's `ADMIN_SHARED_ID` variable — a comma-separated list — and let the service redeploy. Reload, and every comment gains a moderation menu: pin, hide, verify the author, block, delete. Post a test comment, reply to it, and check Mailpit again: a *New comment to your site* message should be waiting. Then copy the embed snippet from `/web/` into your own site.

![Remark42 threaded discussion with markdown and vote scores](https://res.cloudinary.com/rroe4rtk/image/upload/f_auto,q_auto/v1789467070/remark42-comment-thread.webp)
![Remark42 comment editor showing the rendered markdown preview](https://res.cloudinary.com/rroe4rtk/image/upload/f_auto,q_auto/v1789467071/remark42-markdown-preview.webp)
![Mailpit showing a Remark42 new-comment notification email](https://res.cloudinary.com/rroe4rtk/image/upload/f_auto,q_auto/v1789467072/remark42-email-notification.webp)

## About Hosting Remark42

Remark42 replaces a hosted comment service with one Go binary and an embedded BoltDB database. No database server, no queue, no cache tier — the installation is one process and one directory. A five-year-old instance with regular activity fits in under 200 MB, and the backup is a gzipped JSON dump the server writes itself every 24 hours.

Key features:

- Threaded comments with full markdown, code blocks, image uploads and emoji
- Sign-in by email token, anonymous name, or OAuth with GitHub, Google, Microsoft, Apple, Facebook, Yandex, Discord, Patreon or a custom provider
- Voting with score thresholds that hide low-scored comments automatically
- Moderation: pin, hide, verify, delete, block, restricted word and name lists
- Email and Telegram notifications, RSS feeds per thread
- Multi-site support from one instance, and an import path from Disqus and WordPress

The `remark42` service is the whole application — API, widget assets and storage. `mailpit` exists because Remark42's most convenient sign-in method is an emailed token, and a fresh deployment with no SMTP host could not send one. Mailpit captures mail rather than delivering it, so it is a safe place to watch notifications before you point Remark42 at a real relay.

## Why Deploy Remark42 on Railway

Railway removes the server work from a self-hosted comment engine:

- One click provisions both services, both volumes and the public HTTPS domain
- The signing secret is generated at deploy time
- `TRUSTED_PROXY` is pre-set to Railway's edge, so per-IP rate limiting works
- Volumes keep comments across every redeploy
- Health checks on `/ping` and `/livez` catch a bad rollout

## Common Use Cases

- Comments on a static blog built with Hugo, Astro, Eleventy or Next.js, with no third-party tracking script
- Replacing Disqus on an existing site, importing the old threads from a Disqus export
- One instance across several domains, with `SITE` separating each site's comments
- Feedback on internal docs, sign-in restricted to your company's OAuth provider

## Remark42 vs Other Comment Engines

| | Remark42 | Disqus | Commento | Giscus |
|---|---|---|---|---|
| Self-hosted | Yes | No | Yes | No (GitHub) |
| Ads / trackers | None | Yes on free tier | None | None |
| Storage | BoltDB file | Vendor cloud | PostgreSQL | GitHub Discussions |
| Sign-in | Email or OAuth | Disqus account | Email | GitHub only |

Remark42 sits between Giscus, which needs every commenter to hold a GitHub account, and Commento, which needs a PostgreSQL server of its own.

## Dependencies for Remark42

- `umputun/remark42:latest` — the comment engine; API, widget and BoltDB storage in one binary
- `axllent/mailpit:latest` — SMTP server and inbox holding the sign-in tokens and notifications

### Environment Variables Reference

| Variable | Service | Purpose |
|---|---|---|
| `REMARK_URL` | remark42 | Public URL; baked into the widget at every start |
| `SECRET` | remark42 | Signs the auth tokens; keep it stable |
| `SITE` | remark42 | Site id the widget reports, `remark` by default |
| `AUTH_EMAIL_ENABLE` | remark42 | Turns on one-time-token email sign-in |
| `ADMIN_SHARED_ID` | remark42 | Comma-separated moderator user ids |
| `ALLOWED_HOSTS` | remark42 | Restricts which sites may embed the widget |
| `SMTP_HOST` / `SMTP_PORT` | remark42 | Outgoing mail server; points at Mailpit |
| `MP_UI_AUTH` | mailpit | `user:password` for the inbox |

### Deployment Dependencies

- Source: [github.com/umputun/remark42](https://github.com/umputun/remark42) (MIT), [docs](https://remark42.com/docs/getting-started/installation/)
- Images: [umputun/remark42](https://hub.docker.com/r/umputun/remark42), [axllent/mailpit](https://hub.docker.com/r/axllent/mailpit)

## Hardware Requirements for Self-Hosting Remark42

| Resource | Minimum | Recommended |
|---|---|---|
| CPU | 0.25 vCPU | 1 vCPU |
| RAM | 128 MB | 512 MB |
| Storage | 1 GB volume | 5 GB volume |
| Runtime | Docker | Docker |

Upstream reports busy instances idling under 0.1% CPU and around 80 MB of RAM. The volume grows slowly; most of it is images, not comment text.

## Self-Hosting Remark42 with Docker

The minimum is two variables and a mounted directory:

```
docker run -d --name remark42 \
  -p 8080:8080 \
  -e REMARK_URL=https://comments.example.com \
  -e SECRET=change-me-to-a-long-random-string \
  -e AUTH_ANON=true \
  -v $PWD/var:/srv/var \
  umputun/remark42:latest
```

The container refuses to start if `/srv/var` is not mounted — deliberately, since that is where your comments live. Embedding is a snippet plus a target element:

```

<div id="remark42"></div>
```

## How Much Does Remark42 Cost to Self-Host?

Remark42 is MIT-licensed and free — no paid tier, no seat limits, no feature gating. The only cost is infrastructure, which on Railway means usage-based pricing for two small containers and two volumes. Disqus removes ads only on a paid plan, and Hyvor Talk charges per page view.

## FAQ

**What is Remark42?**
Remark42 is a self-hosted, open-source commenting engine written in Go. You embed it on any web page with a script tag, and it stores comments in a BoltDB file you own rather than in a vendor's cloud.

**What does this Railway template deploy?**
Two services: `remark42`, the comment engine on a public HTTPS domain with a volume at `/srv/var`, and `mailpit`, a private SMTP server with a password-protected inbox that receives the sign-in tokens and notification emails.

**Why does the template include a mail service?**
Remark42's email sign-in mails a one-time token, and its notifications are email too. Without an SMTP host neither works, so a deployment with no mail service has no usable login unless you enable anonymous commenting. Point `SMTP_HOST` and `SMTP_PORT` at a real relay when you go live.

**How do I make myself an admin in self-hosted Remark42?**
There is no admin account. Sign in once, click your username in the widget to reveal your user id, and add it to `ADMIN_SHARED_ID` on the `remark42` service. Moderation controls appear on the next load.

**Can I use GitHub or Google sign-in instead of email?**
Yes. Register an OAuth application, point its callback at `https://your-domain/auth/github/callback`, and set `AUTH_GITHUB_CID` and `AUTH_GITHUB_CSEC`. Several providers can be enabled at once.

**Will my comments survive a redeploy?**
Yes. Everything lives on the volume at `/srv/var` — the BoltDB file, avatars, uploads and the daily backup — and Railway keeps that volume across deployments.

**Can one instance serve several websites?**
Yes. Set `SITE` to a comma-separated list of ids and give each page's `remark_config.site_id` the matching value. Each site gets its own database file and threads.


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