Cryptpad might be something for you. It has a special focus on privacy:
CryptPad is a private-by-design alternative to popular office tools
and cloud services. All the content stored on CryptPad is encrypted
before being sent, which means nobody can access your data unless you
give them the keys (not even us).
It offers most of the usual office-type apps ...
Expanding on @Sir Muffington's answer (posting here an answer because comments are not permanent):
"The FOSS alternative to Twitter" - not a Facebook clone, but close enough. This is the closest answer for what I was looking for.
This seems to be a larger initiative, comprised of a platform and different clients, with an emphasis ...
Provided your batch is a Bash script behind the firewall, the ideal way to this would be AWS API Manager.
Make some counter in your shell script, which will be incremented and after reaching some value it will update some S3 bucket
The update in bucket files will invoke Lambda function which will update some global variable
You can create API ...
Telegram has a Bot API that does exactly what you seek.
They have samples for all the possible programming languages, so it's totally not a problem.
Going through your requirements:
offers an api to integrate in my development environment
offers a web application to use within a browser
it should be easy for me to add new users to my messaging ...
We have setup Microsofts product line for our clients to replace Access. You could either utilize sharepoint, or a better option visually, the Common Data Service. It is not too expensive depending on how many users you have. I believe $35/m for one user to set up everything, and then at least $4 for each user that needs access to this data to make edits.
It's expensive, but a custom web application with a robust database backend may be what you need to meet your fairly specific needs, as well as the scale of your data. The Access database could be migrated to SQL Server using SQL Server Migration Assistant for Access and the business logic would have to be replicated in a web app (the obvious choice being a ....