posteingang

A collection of tools to publish blog posts from your email client.

Packages

Package	Binary	Description
@posteingang/mailmd	mailmd, mdmail	Convert .eml ↔ Markdown
@posteingang/api	mdapi	Generate static JSON API from mailmd output
@posteingang/dog	dog	Watch an inbox folder and run the full pipeline

Data flow

.eml file
  → mailmd  → dist/YYYY-MM-DD-HHmmss/message.md + images
  → mdapi   → dist/posts.json + dist/posts/{slug}.json

Both mailmd output and JSON API share the same dist/ directory.

---

mailmd

Converts .eml files to Markdown directories. HTML is converted to Markdown, embedded images are extracted and resized, and email headers become YAML frontmatter.

mailmd [file] [-o <dir>]

Argument / Option	Default	Description
[file]	stdin	.eml file to convert
-o, --out <dir>	$OUT_DIRECTORY or ./out	Output directory

Output structure:

./out/YYYY-MM-DD-HHmmss/
├── message.md
├── image0.jpg
└── ...

Frontmatter fields: id, date, updatedAt, title, tags (if present), assets (images with width/height/orientation). Additional fields can be embedded in the email body as a YAML block.

mdmail

Reverse converter — turns a mailmd output folder back into a nodemailer config JSON.

mdmail <folder> [-f <from>] [-t <to>] [-s <subject>]

---

mdapi

Scans a dist/ directory for message.md files and generates a Strapi v5-compatible static JSON API. Posts with published: false are excluded.

mdapi [dir] [-a <adapter>]

Argument / Option	Default	Description
[dir]	./dist	dist directory
-a, --adapter <name>	strapi5	API adapter

Output:

./dist/
├── posts.json           # list with pagination envelope
└── posts/
    └── YYYY-MM-DD-HHmmss.json

---

dog

Daemon that watches an inbox folder for .eml files, converts them with mailmd, rebuilds the API, and optionally verifies the sender via a hash in the recipient address.

dog [in] [dist] [-d <url>] [-s <salt>]

Argument / Option	Default	Description
[in]	./in	Inbox folder to watch
[dist]	./dist	Output folder for posts and API
-d, --deploy-hook <url>	—	Webhook URL to POST to after each API rebuild
-s, --salt <value>	—	HMAC-SHA256 salt for sender verification (see below)

Sender verification

When --salt is set, dog only processes emails where the recipient address contains a valid HMAC of the sender's address:

inbox+HASH@yourdomain.com

HASH = first N hex characters of HMAC-SHA256(salt, from@address). Emails that fail the check are deleted. Generate a hash with:

pnpm hashmail YOUR_SALT sender@example.com

---

Development

pnpm install

pnpm test          # run tests
pnpm test:watch    # run tests in watch mode

pnpm lint          # lint
pnpm lint:fix      # lint + auto-fix
pnpm format        # format

License

None yet, subject to change.