How Watched-Folder Auto-Delivery Works on MangaSendr (2026 Guide)

Auto-delivery is the feature that lets you stop opening the app every time you save a new manga volume. Point the MangaSendr desktop app at a folder — your Downloads, a cloud-sync folder, a NAS mount, wherever your manga lands. From that point on, new CBZ, EPUB, PDF, or image folders get converted and emailed to your Kindle on their own. No browser tab to open, no button to press.

This guide walks through exactly what happens behind the scenes, what knobs you can turn, and what's included in the free trial.

The 30-second version

Install the MangaSendr desktop app (macOS or Windows).
In the app, pick a watched folder on your disk.
Register the Kindle you want deliveries to go to.
Drop a file into the watched folder. MangaSendr detects it, converts it to a Kindle-perfect EPUB, emails it to your Kindle.
Every future file in that folder follows the same pipeline, automatically.

That's it. The rest of this page is the details for people who like to know how the sausage is made.

What "auto-delivery" actually means

Auto-delivery is two separate things working together:

Folder watching. A background process on your computer watches the folder you picked. The moment a new file appears — downloaded, copied, moved, sync'd from the cloud — the app notices and queues it for processing.

Silent delivery. When a new file is picked up, the desktop app packages it into a Kindle-perfect EPUB, optimizes the images for e-ink (sharpening, dithering, contrast), splits it if it's bigger than Amazon's 50MB Send-to-Kindle cap, and sends the file to your Kindle email address. You can also toggle USB transfer as the delivery method instead, for devices that accept USB sideloads.

You enable auto-delivery on a per-device basis. Every Kindle you've registered has an "Auto-deliver new files" checkbox in its device settings. By default it's on for new devices.

What formats get picked up

The watcher is not picky. It detects:

CBZ / CBR archives — the common scanlation format.
EPUB files — delivered as-is after re-optimization for your device.
PDF scans — unpacked, the pages are re-sized and re-compressed for e-ink.
Folders of images (JPG, PNG, WebP) — treated as a single volume, packed into an EPUB.

Anything that isn't one of the above (a stray .txt file, a .nfo, a hidden .DS_Store) is ignored. The watcher also waits until a file is fully written before queuing it — so in-progress downloads don't kick off half-conversion jobs.

How fast does auto-delivery react?

The watcher uses the OS's native filesystem events, so it notices new files within a second or two. The conversion itself typically takes 20 to 60 seconds depending on file size and image count. Delivery to Amazon is another 30 to 60 seconds. End-to-end, a file usually lands on your Kindle two to three minutes after it arrives in the watched folder.

If you're on the subscribed plan, conversion runs in a priority queue which is usually 2× faster at peak hours.

Multi-device fan-out

If you have more than one Kindle registered with auto-delivery enabled, each new file gets delivered to all of them. Useful if you read on a Paperwhite at home and a Scribe on the train.

The free trial and auto-delivery

Every new account starts with a 7-day free trial — no credit card required — and it unlocks everything: unlimited manual sends from the web app, unlimited watched-folder auto-deliveries, and the desktop app itself.

Practically:

During the trial, every file that lands in the watched folder is converted and delivered to your Kindle, with no cap.
When the trial ends, the watcher still detects new files but won't deliver them. The conversion queue holds them, and they deliver automatically once you subscribe ($2.99/mo or $24.99/yr).
Subscribe with a card before your trial ends and your first month is free — anything queued keeps flowing without interruption.

We surface trial status in two places: the desktop app shows how many trial days you have left in the status bar, and the web app shows the same in the navbar.

Where to see what auto-delivery is doing

Desktop app status bar. Shows the active watched folder, the last file picked up, the current queue length, and your trial or subscription status.

Desktop app log. Every file detection, conversion, and delivery gets a log line with timestamp and status. Useful for confirming "yes, the file I just saved did actually get picked up."

Web app delivery history. Auto-deliveries are flagged with a small "Auto" badge next to the filename. You can also filter the entire list to show only manual or only auto deliveries.

Prefer manual control? You can also download chapters as EPUB files directly from the web app — great for Kobo, Android, or any e-reader where Send-to-Kindle email isn't an option.

Discord notifications (subscribers). Optional pings on auto-delivery starts, completions, and failures. Useful if you want to know the second a file lands instead of going to your Kindle to check.

What can go wrong

The file is in an unsupported format. Anything that isn't CBZ/CBR/EPUB/PDF/image-folder gets skipped. Check the log if a file you expected to pick up didn't.

The file is corrupted or incomplete. If the conversion step fails, the delivery is marked as failed in the log. You can re-trigger it from the web app's delivery history once the file is fixed.

The file is over Amazon's 50MB Send-to-Kindle limit. We auto-detect this and run Smart Split to chunk the file into multiple parts ("Vol 1 of 3", "Vol 2 of 3", etc.). You'll see the parts arrive sequentially on the Kindle.

The sender address isn't whitelisted. This is by far the most common cause of "I configured everything but nothing arrived on my Kindle." Amazon silently drops emails from non-approved senders. Open Amazon → Manage Your Content and Devices → Preferences → Personal Document Settings and add delivery@mangasendr.com to the Approved Personal Document E-mail List.

Your watched folder is on a network drive that's disconnected. The watcher pauses until the mount comes back, then resumes.

Disabling auto-delivery

You can turn auto-delivery off on a per-device basis. Go to Settings → Devices → Edit in either the web app or the desktop app, and uncheck "Auto-deliver new files." The watcher keeps picking up files (so you can still see them in your library), but nothing gets emailed to that device until you flip it back on.

If you want to pause the watcher entirely, the desktop app has a Pause toggle in the status bar. Click it to stop file detection. Click again to resume.

Can the web app do auto-delivery too?

Not really — the web app runs in a browser tab, and browsers can't watch local folders without an open tab and explicit permission for each file. The web app is the manual upload path: drag a file in, hit send. If you want "it happens on its own" behavior, install the desktop app. Same account, same settings.

TL;DR

Watched-folder auto-delivery is the entire reason to install the MangaSendr desktop app. You set it up once (pick a folder, register a Kindle, whitelist the sender) and it does the work. Files land on your Kindle two to three minutes after they hit the folder. The 7-day free trial includes all of it; subscribers keep unlimited deliveries and priority conversion.

Start your free 7-day trial →