This guide will not go about how to create .deb files or how to configure a webserver.
The basic idea is to add your .deb files to a folder where your webserver will serve.
Then run a script to generate the needed files (Packages, Release, etc).
Idea based on this response on askubuntu.com
sudo apt install dpkg-dev gnupg
The only thing that needs to be adjusted is the repository folder in the cd call.
Change /var/www/html/debian to where you are hosting the repo.
#!/bin/bash
cd /var/www/html/debian
# Generate the Packages file
dpkg-scanpackages . /dev/null > Packages
gzip --keep --force -9 Packages
# Generate the Release file
# cat conf/distributions > Release ## this can be ignored
# The Date: field has the same format as the Debian package changelog entries,
# that is, RFC 2822 with time zone +0000
echo -e "Date: `LANG=C date -Ru`" >> Release
# Release must contain MD5 sums of all repository files (in a simple repo just the Packages and Packages.gz files)
echo -e 'MD5Sum:' >> Release
printf ' '$(md5sum Packages.gz | cut --delimiter=' ' --fields=1)' %16d Packages.gz' $(wc --bytes Packages.gz | cut --delimiter=' ' --fields=1) >> Release
printf '\n '$(md5sum Packages | cut --delimiter=' ' --fields=1)' %16d Packages' $(wc --bytes Packages | cut --delimiter=' ' --fields=1) >> Release
# Release must contain SHA256 sums of all repository files (in a simple repo just the Packages and Packages.gz files)
echo -e '\nSHA256:' >> Release
printf ' '$(sha256sum Packages.gz | cut --delimiter=' ' --fields=1)' %16d Packages.gz' $(wc --bytes Packages.gz | cut --delimiter=' ' --fields=1) >> Release
printf '\n '$(sha256sum Packages | cut --delimiter=' ' --fields=1)' %16d Packages' $(wc --bytes Packages | cut --delimiter=' ' --fields=1) >> Release
# Clearsign the Release file (that is, sign it without encrypting it)
gpg --clearsign --digest-algo SHA512 --local-user $USER -o InRelease Release
# Release.gpg only need for older apt versions
# gpg -abs --digest-algo SHA512 --local-user $USER -o Release.gpg ReleaseSave the script as /usr/sbin/makeRepo
Make it executable chmod +x /usr/sbin/makeRepo
Run the script as the webserver user www-data
sudo -u www-data /usr/sbin/makeRepo
You may run as root, but then you will probably need to chown -R www-data:www-data /var/www/html/debian
This should be enough to get your repository running (without the need for the unsigned flag).