📝 Guestbook

I started working on Madblog a few years ago.

I wanted a simple blogging platform that I could run from my own Markdown files. No intermediaries. No bloated UI. No JavaScript. No databases and migration scripts. No insecure plugins. Just a git folder, an Obsidian vault or a synchronized SyncThing directory, and the ability to create and modify content by simply writing text files, wherever I am.

Drop a Markdown file in the directory, and it's live. Edit it, and the changes propagate. Delete it, and it's gone.

It's been running my personal blog and the Platypush blog for a while now.

With the new release, #madblog now gets a new superpower: it supports federation, interactions and comments both through:

• Webmentions - already implemented some weeks ago, you can also check out the previous blog article
• ActivityPub

Webmentions allow your site to mention and be mentioned by other sites that also implement them - like any WordPress blog with the Webmention plugin, or link aggregators like Lemmy or HackerNews. Interactions with any of your pages will be visible under them.

#activitypub support allows Madblog to fully federate with Mastodon, Pleroma, Misskey, Friendica or any other #fediverse instance. It turns your blog into a federated handle that can be followed by anyone on the Fediverse. It gives you the ability to mention people on the Fediverse directly from your text files, and get replies to your articles directly from Mastodon, get your articles boosted, shared and quoted like any other Mastodon post.

Demos

These blogs are powered by Madblog:

• blog.fabiomanganiello.com — Fediverse handle: @fabio@manganiello.blog
• blog.platypush.tech — Fediverse handle: @blog@platypush.tech

You can follow them from Mastodon (or any other Fediverse client), reply to articles directly from your instance, boost them, or quote them. You can also interact via Webmentions: link to an article from your own site, and if your site supports Webmentions, the mention will show up as a response on the original post. These blogs also have a Guestbook — mention the blog's Fediverse handle or send a Webmention to the home page, and your message appears on a public guest registry.

How Does It Compare?

If you've looked into federated blogging before, you've likely come across a few options:

• WriteFreely is probably the closest alternative — a minimalist, Go-based platform with ActivityPub support. It's well-designed, but it uses a database (SQLite or MySQL), has its own (very minimal) editor, and doesn't support Webmentions. Additionally, it lacks many features that are deal-breakers for me.
• No export of all the content to Markdown, nor ability to run my blog from my Nextcloud Notes folder or Obsidian vault.
• No support for LaTeX or Mermaid diagrams.
• No support for federated interactions - any interaction with your articles on the Fediverse is simply lost.
• The UI is minimalist and not necessarily bad, but not even sufficiently curated for something like a blog (narrow width, Serif fonts not optimized for legibility, the settings and admin panels are a mess...).
• No support for moderation / content blocking.

• No support for federated hashtags.

• WordPress with ActivityPub and Webmention plugins can technically do what Madblog does, but it's a full CMS with a database, a theme engine, a plugin ecosystem, and a much larger attack surface. If all you need is a blog, it's overkill.

• Plume and Friendica offer blogging with federation, but they're full social platforms, not lightweight publishing tools.

Madblog sits in a different niche: it's closer to a static-site generator that happens to speak federation protocols. It implements a workflow like "write Markdown, push to server, syndicate everywhere".

Getting Started Docker Quickstart

mkdir -p ~/madblog/markdown
cat <<EOF > ~/madblog/markdown/hello-world.md

This is my first post on [Madblog](https://git.fabiomanganiello.com/madblog)!
EOF

docker run -it \
  -p 8000:8000 \
  -v "$HOME/madblog:/data" \
  quay.io/blacklight/madblog

Open http://localhost:8000. That's it — you have a blog.

The default Docker image (quay.io/blacklight/madblog) is a minimal build (< 100 MB) that includes everything except LaTeX and Mermaid rendering. If you need those, build the full image from source:

git clone https://git.fabiomanganiello.com/madblog
cd madblog
docker build -f docker/full.Dockerfile -t madblog .

See the full Docker documentation for details on mounting config files and ActivityPub keys.

Markdown structure

Since there's no database or extra state files involved, the metadata of your articles is also stored in Markdown.

Some things (like title, description) can be inferred from the file name, headers of your files etc., creation date defaults to the creation timestamp of the file and author and language are inherited from your config.yaml.

A full customized header would look like this:

 [//]: # (title: Title of the article)
 [//]: # (description: Short description of the content)
 [//]: # (image: /img/some-header-image.png)
 [//]: # (author: Author Name <https://author.me>)
 [//]: # (author_photo: https://author.me/avatar.png)
 [//]: # (language: en-US)
 [//]: # (published: 2022-01-01)

...your Markdown content...

Key Configuration

Madblog reads configuration from a config.yaml in your content directory. Every option is also available as an environment variable with a MADBLOG_ prefix — handy for Docker or CI setups.

A minimal config to get started:

title: My Blog
description: Thoughts on tech and life
link: https://myblog.example.com
author: Your Name

Or purely via environment variables:

docker run -it \
  -p 8000:8000 \
  -e MADBLOG_TITLE="My Blog" \
  -e MADBLOG_LINK="https://myblog.example.com" \
  -e MADBLOG_AUTHOR="Your Name" \
  -v "$HOME/madblog:/data" \
  quay.io/blacklight/madblog

See config.example.yaml for the full reference.

It is advised to keep all of your Markdown content under <data-dir>/markdown, especially if you enable federation, in order to keep the Markdown folder tidy from all the auxiliary files generated by Madblog.

Webmentions

Webmentions are the IndieWeb's answer to trackbacks and pingbacks — a W3C standard that lets websites notify each other when they link to one another. Madblog supports them natively, both inbound and outbound.

When someone links to one of your articles from a Webmention-capable site, your blog receives a notification and renders the mention as a response on the article page. Going the other way, when you link to an external URL in your Markdown and save the file, Madblog automatically discovers the target's Webmention endpoint and sends a notification — no manual step required. All mentions are stored as Markdown files under your content directory (mentions/incoming/<post-slug>/), so they're version-controllable and easy to inspect.

You can enable pending-mode for moderation (webmentions_default_status: pending), or use the blocklist/allowlist system to filter sources by domain, URL, or regex. Webmentions are enabled by default — if you're running Madblog locally for testing, set enable_webmentions: false to avoid sending real notifications to external sites.

ActivityPub Federation

ActivityPub is the protocol that powers the Fediverse — Mastodon, Pleroma, Misskey, and hundreds of other platforms. Madblog implements it as a first-class feature: enable it, and your blog becomes a Fediverse actor that people can follow, reply to, boost, and quote.

Enable it in your config:

enable_activitypub: true
activitypub_username: blog
activitypub_private_key_path: /path/to/private_key.pem

Madblog will generate an RSA keypair on first start if you don't provide one. Once enabled, your blog gets a Fediverse handle (@blog@yourdomain.com), a WebFinger endpoint for discovery, and a full ActivityPub actor profile. New and updated articles are automatically delivered to all followers' timelines.

Here's what federation looks like in practice:

• Receiving mentions: when someone mentions your blog's Fediverse handle in a public post (not as a reply to a specific article), the mention shows up on your Guestbook page.
• Receiving replies, likes, boosts, and quotes: interactions targeting a specific article are rendered below that article — replies as threaded comments, likes/boosts/quotes as counters and cards. All stored as JSON files on disk.
• Sending mentions: just write the fully-qualified handle in your Markdown (@alice@mastodon.social) and save the file. Madblog resolves the actor via WebFinger and delivers a proper ActivityPub Mention tag — the mentioned user gets a notification on their instance.
• Federated hashtags: hashtags in your articles (#Python, #Fediverse) are included as ActivityPub Hashtag tags in the published object. Followers who track those hashtags on their instance will see your posts in their filtered feeds.
• Custom profile fields: configure additional profile metadata (verified links, donation pages, git repos) that show up on your actor's profile as seen from Mastodon and other Fediverse clients:

yaml activitypub_profile_fields: Git repository: <https://git.example.com/myblog> Donate: <https://liberapay.com/myprofile>

The federation layer also exposes a read-only subset of the Mastodon API, so Mastodon-compatible clients and crawlers can discover the instance, look up the actor, list published statuses, and search for content — with no extra configuration.

Madblog also supports advanced ActivityPub features like split-domain setups (e.g. your blog at blog.example.com but your Fediverse handle at @blog@example.com), configurable object types (Note for inline rendering on Mastodon vs. Article for link-card previews), and quote policies (FEP-044f, so Mastodon users can quote your articles too).

LaTeX and Mermaid

Madblog supports server-side rendering of LaTeX equations and Mermaid diagrams directly in your Markdown files — no client-side JavaScript required.

LaTeX uses latex + dvipng under the hood. Inline expressions use conventional LaTeX markers:

The Pythagorean theorem states that \(c^2 = a^2 + b^2\).

$$
E = mc^2
$$

Mermaid diagrams use standard fenced code blocks. Both light and dark theme variants are rendered at build time and switch automatically based on the reader's color scheme:

 ```mermaid
 graph LR
     A[Write Markdown] --> B[Madblog renders it]
     B --> C[Fediverse sees it]
 ```

Install Mermaid support with pip install "madblog[mermaid]" or use the full Docker image. Rendered output is cached, so only the first render of each block is slow.

Tags and Categories

Tag your articles with hashtags — either in the metadata header or directly in the body text:

[//]: # (tags: #python, #fediverse, #blogging)

# My Article

This post is about #Python and the #Fediverse.

Madblog builds a tag index at /tags, with per-tag pages at /tags/<tag>. Hashtags from incoming Webmentions are also indexed. Folders in your content directory act as categories — if you organize files into subdirectories, the home page groups articles by folder.

Feed Syndication

Madblog generates both RSS and Atom feeds at /feed.rss and /feed.atom. You can control whether feeds include full article content or just descriptions (short_feed: true), and limit the number of entries (max_entries_per_feed: 10). limit and offset parameters are also supported for pagination.

Aggregator Mode

Madblog can also pull in external RSS/Atom feeds and render them alongside your own posts on the home page — useful for affiliated blogs, or even as a self-hosted feed reader:

external_feeds:
  - https://friendsblog.example.com/feed.atom
  - https://colleaguesblog.example.com/feed.atom

Guestbook

The guestbook (/guestbook) is a dedicated page that aggregates public interactions — Webmentions targeting the home page and Fediverse mentions of your blog actor that aren't replies to specific articles. Think of it as a public guest registry, or a lo-fi comment section for your blog as a whole. Visitors can leave a message by mentioning your Fediverse handle or sending a Webmention. It can be disabled via enable_guestbook=0.

View Modes

The home page supports three layouts:

• cards (default) — a responsive grid of article cards with images
• list — a compact list with titles and dates
• full — a scrollable, WordPress-like view with full article content inline

Set it in your config (view_mode: cards) or override at runtime with ?view=list.

Moderation

Madblog ships with a flexible moderation system that applies to both Webmentions and ActivityPub interactions. You can run in blocklist mode (reject specific actors) or allowlist mode (accept only specific actors), with pattern matching by domain, URL, ActivityPub handle, or regex:

blocked_actors:
  - spammer.example.com
  - "@troll@evil.social"
  - /spam-ring\.example\..*/

Moderation rules also apply retroactively — interactions already stored are filtered at render time. Blocked ActivityPub followers are excluded from fan-out delivery and hidden from the public follower count, but their records are preserved so they can be automatically reinstated if you change your rules.

Email Notifications

Configure SMTP settings and Madblog will notify you by email whenever a new Webmention or ActivityPub interaction arrives — likes, boosts, replies, mentions, and quotes:

author_email: you@example.com
smtp_server: smtp.example.com
smtp_username: you@example.com
smtp_password: your-password

Progressive Web App

Madblog is installable as a PWA, with offline access and a native-like experience on supported devices. A service worker handles stale-while-revalidate caching with background sync for retries.

Raw Markdown Access

Append .md to any article URL to get the raw Markdown source:

https://myblog.example.com/article/my-post.md

Useful for readers who prefer plain text, or for tools that consume Markdown directly.

Reusable Libraries

Two key subsystems of Madblog have been extracted into standalone, reusable Python libraries. If you're building a Python web application and want to add decentralized federation support, you can use them directly — no need to adopt Madblog itself.

Webmentions

Webmentions is a general-purpose Python library for sending and receiving Webmentions. It comes with framework adapters for FastAPI, Flask, and Tornado, pluggable storage backends (SQLAlchemy or custom), filesystem monitoring for auto-sending mentions when files change, full microformats2 parsing, and built-in HTML rendering for displaying mentions on your pages.

Adding Webmentions to a FastAPI app:

from fastapi import FastAPI
from webmentions import WebmentionsHandler
from webmentions.storage.adapters.db import init_db_storage
from webmentions.server.adapters.fastapi import bind_webmentions

app = FastAPI()
storage = init_db_storage(engine="sqlite:////tmp/webmentions.db")
handler = WebmentionsHandler(storage=storage, base_url="https://example.com")
bind_webmentions(app, handler)

That's it — your app now has a /webmentions endpoint for receiving mentions, a Link header advertising it on every response, and a storage layer for persisting them. See the full documentation for details on sending mentions, custom storage, moderation, and rendering.

Pubby

Pubby is a general-purpose Python library for adding ActivityPub federation to any web application. It handles inbox processing, outbox delivery with concurrent fan-out, HTTP Signatures, WebFinger/NodeInfo discovery, interaction storage, a Mastodon-compatible API, and framework adapters for FastAPI, Flask, and Tornado.

Adding ActivityPub to a FastAPI app:

from fastapi import FastAPI
from pubby import ActivityPubHandler, Object
from pubby.crypto import generate_rsa_keypair
from pubby.storage.adapters.db import init_db_storage
from pubby.server.adapters.fastapi import bind_activitypub

app = FastAPI()
storage = init_db_storage("sqlite:////tmp/pubby.db")
private_key, _ = generate_rsa_keypair()

handler = ActivityPubHandler(
    storage=storage,
    actor_config={
        "base_url": "https://example.com",
        "username": "blog",
        "name": "My Blog",
        "summary": "A blog with ActivityPub support",
    },
    private_key=private_key,
)

bind_activitypub(app, handler)

# Publish a post to all followers
handler.publish_object(Object(
    id="https://example.com/posts/hello",
    type="Note",
    content="<p>Hello from the Fediverse!</p>",
    url="https://example.com/posts/hello",
    attributed_to="https://example.com/ap/actor",
))

Optionally, you can also expose a Mastodon-compatible API so that Mastodon clients and crawlers can discover your instance and browse statuses:

from pubby.server.adapters.fastapi_mastodon import bind_mastodon_api

bind_mastodon_api(
    app,
    handler,
    title="My Blog",
    description="A blog with ActivityPub support",
)

Both libraries follow the same design philosophy: provide the protocol plumbing so you can wire it into your existing application with minimal ceremony. Storage is pluggable (SQLAlchemy, file-based, or bring-your-own), framework binding is a single function call, and the core logic is framework-agnostic. See the full documentation for Pubby and Webmentions.

Links

• Madblog (Github mirror)
• Webmentions (Github mirror)
• Pubby (Github mirror)

Madblog is open-source under the AGPL-3.0-only license. The source code, issue tracker, and full documentation are available at git.fabiomanganiello.com/madblog.