Synchronet v3.17b-Win32 (install) has been released (Jan-2019).

New Synchronet YouTube channel

You can donate to the Synchronet project using PayPal.

This is an old revision of the document!

Table of Contents


LetSyncrypt is a Let's Encrypt client for Synchronet which uses the ACMEv2 protocol.


LetSyncrypt should be added as a timed event.

Add the Timed Event in SCFG->External Programs->Timed Events:

Internal Code                   SYNCRYPT
Start-up Directory
Command Line                    ?letsyncrypt.js
Enabled                         Yes
Execution Node                  1
Execution Months                Any
Execution Days of Month         Any
Execution Days of Week          All
Execution Frequency             1 times a day
Requires Exclusive Execution    No
Force Users Off-line For Event  No
Native Executable               No
Use Shell to Execute            No
Background Execution            No
Always Run After Init/Re-init   Yes

If you have multiple domain names, you can have LetSyncrypt put them all in a single certificate, even if you have virtual hosts. Edit the ctrl/letsyncrypt.ini file and add a [Domains] section where the key is the hostname, and the value is the web root for that domain:


This example has four domains (,,, and The last two are virtual hosts, so have their web root as a subdirectory of the main web root.

Do not modify any other sections of this file.

Important Caveat

At present (February 24, 2018), Let's Encrypt does not support ACMEv2 for trusted certificates. The server is expected to go live on February 27, 2018. On that date, letsyncrypt.js will be updated to use the newly announced server (likely Until then, installed certificates will not be trusted, being issued by the staging server, signed by “Fake LE Intermediate X1”.

See Also

In Other Languages
Translations of this page: