Send to E-Reader

Convert web articles to EPUB and email them straight to your e-reader. Works with any device that accepts emailed files — Kindle, PocketBook, or anything else with a similar service.

Built with Express 5 + TypeScript. Hosted at read.atanasov.fi.

How it works

Two ways to send something to your e-reader:

URL → EPUB

1. You paste an article URL and your e-reader's email address.
2. The server fetches the page, runs Mozilla Readability over it to strip ads/chrome, builds an EPUB, and emails it to the address you gave.
3. The EPUB is deleted from the server immediately after sending.

Upload a file

1. Drag (or pick) a file — EPUB, PDF, MOBI, anything your device accepts.
2. The server attaches it to an email and sends it to your e-reader as-is, no conversion.
3. The file is deleted from the server immediately after sending. Max size: 25 MB.

Supported devices

The destination email domain is checked against an allowlist (default: kindle.com, pbsync.com) to prevent the app being used as an open email relay. Subdomains count, so free.kindle.com works too.

Device	Email pattern
Amazon Kindle	*@kindle.com (or *.kindle.com subdomains)
PocketBook	*@pbsync.com

You can extend the list via the ALLOWED_READER_DOMAINS env var (see below).

You'll also need to add the sender address to your device's approved-senders list — one-time per device.

Prerequisites

• Node.js 20 or newer
• An SMTP-capable email provider. Defaults are set up for Resend — sign up (no waitlist), verify your domain, grab an API key.

Local development

git clone <your-fork>
cd send_to_kindle
npm install
cp .env.example .env   # then fill in SMTP_PASSWORD (Resend API key) and MAIL_FROM
npm run dev

Server listens on http://localhost:3000 (override with PORT).

Production build

npm run build
npm run start

Environment variables

Variable	Required	Default	Notes
SMTP_HOST	no	smtp.resend.com	Any SMTP server works
SMTP_PORT	no	587	587 = STARTTLS (preferred — port 465 is blocked by most VPS providers)
SMTP_USER	yes	—	For Resend, literally the string resend
SMTP_PASSWORD	yes	—	For Resend, your API key (re_…)
MAIL_FROM	yes	—	Sender address, e.g. read@atanasov.fi. Must be from a verified domain on your provider.
ALLOWED_READER_DOMAINS	no	kindle.com,pbsync.com	Comma-separated allowlist of destination email domains. Suffix-matching, so subdomains are allowed.
PORT	no	3000	Listen port

Resend setup (quick)

1. Sign up at resend.com.
2. Add your domain (e.g. atanasov.fi) and add the SPF/DKIM/return-path DNS records they generate. Verification usually completes in a few minutes.
3. Create an API key.
4. In .env:

   SMTP_USER=resend
   SMTP_PASSWORD=re_xxxxxxxxxxxxxxxxxx
   MAIL_FROM=send@read.atanasov.fi
   

For a different provider, just point SMTP_HOST / SMTP_PORT / SMTP_USER / SMTP_PASSWORD at it — any standard SMTP service works.

API

POST /send-article

Body (JSON):

{
  "url": "https://example.com/article",
  "readerEmail": "your-device@kindle.com"
}

Response on success:

{
  "success": true,
  "message": "Article sent to your e-reader",
  "title": "Article Title"
}

POST /send-file

Body (multipart/form-data):

• file — the binary file (max 25 MB)
• readerEmail — destination address

Response on success:

{
  "success": true,
  "message": "File sent to your e-reader",
  "title": "original-filename.epub"
}

Rate limit

Both endpoints share a limit of 20 sends per IP per hour.

Limitations

• Articles must be publicly accessible — no paywalled or login-required pages.
• Server-side fetch means JS-heavy SPAs may extract poorly (the page must render meaningful HTML without JavaScript).
• Some sites block non-browser user-agents; the app sends a Chrome UA but can still be refused.

Stack

• Express 5 — HTTP server
• @mozilla/readability — article extraction
• jsdom — DOM for Readability
• @lesjoursfr/html-to-epub — EPUB generation
• nodemailer — SMTP client
• multer — multipart/form-data upload parsing
• express-rate-limit — per-IP rate limiting

License

GPL-3.0-only. See LICENSE.