Adding modules to your Backdrop site

Backdrop keeps this simpler than Drupal 7 did — one folder is yours, it already exists, and code you put there wins.

Where your modules go

sites/<yourdomain>/modules/ is the place. It's created writable for your shell and SFTP user on every site, no unlocking needed, and it's the last place Backdrop looks when scanning for modules — so anything you put there outranks the platform's own copies. Your uploads are never swept: the nightly housekeeping removes only leftover .tar/.zip archives (unpack, then let it tidy the wrapper), and none of BOA's Drupal module enforcement applies to Backdrop sites — nothing here force-enables or force-disables your modules.

Two places that look right and aren't:

sites/all/modules does not work on Backdrop. Unlike Drupal, Backdrop has no sites/all layer at all. The folder exists here (BOA keeps platform control files in it), and the panel's package listing will even report a module placed there — but Backdrop itself never loads code from it. A module uploaded there is a silent no-op.
The platform's root modules/ is BOA's. That's where the shared contrib bundle lives (today it delivers the Valkey/Redis cache module to every Backdrop platform — already wired, nothing to enable). It's maintained together with the platform; your additions belong in your site's own folder, which outranks it anyway.

One practical note: your site folder itself (the parent of modules/) isn't writable — you can't create sibling folders next to modules/. To replace a module, delete the old copy rather than trying to park it.

Three ways to get a module in

bee download from your shell. Connect as your shell user, cd into the site directory (as its own command — the limited shell refuses cd … && … one-liners), and:
SH
```
bee download webform
```
It fetches the newest release from the Backdrop project server straight into your site's modules/ folder. Then bee enable webform and you're done.
SFTP upload. Put the unpacked module folder into ~/platforms/<NNN>/<platform>/<yourdomain>/modules/. Same place, same result.
Backdrop's own UI. Functionality → Install new modules works too, and writes to the same folder.

Not every Backdrop port is packaged the same way: most live on the Backdrop project server with proper releases (bee download finds those), a few exist only as Git repositories, and some Drupal 7 staples need no port at all — ctools is the famous example, whose Backdrop project page says it plainly: core has covered its tools since 1.0, and there is no reason to install it.

Filling a port gap after a Drupal 7 upgrade

The Drupal 7 upgrade leaves a module without a present port disabled on the copy, with its data tables kept. Filling that gap afterwards is a short routine — worked example with Webform, which has a full Backdrop port:

Delete the Drupal 7 copy from the new site's modules/ folder — the conversion carried it over as files, and it must not sit next to the port. Your original is safe: the Drupal 7 site still holds it.
SH
```
rm -rf modules/webform
```
Download the port, from the site directory:
SH
```
bee download webform
```
Enable it and run the database updates:
SH
```
bee enable webform
bee updb -y
```
This is where the kept data pays off: the module's tables still carry their Drupal 7 schema, and the update run converts them — the port's updates apply from exactly where Drupal 7 left off, and your data comes out the other side as native Backdrop content.

Order matters: replace the code first, then enable. bee enable doesn't check compatibility — it will happily enable the leftover Drupal 7 copy on your Backdrop site, which plants a landmine that detonates on whatever page first touches the module's code. If that's already happened, disable it, replace the code as above, and update.

Where to go next

Your Backdrop site, day to day — bee, configuration and what BOA already handles.
Upgrading from Drupal 7 — the module compatibility report that tells you which gaps you'll have.
Modules BOA manages — the Drupal-side module policy, none of which applies here.