Using the great Open FaaS, you can easily check-in on Swarm/Foursquare by making a request to this function. Be sure to supply your own OAuth token and venue ID in the stack.yml.

Follow the instructions on the FaaS repo to deploy the Faas stack.

Get the CLI

You can install the faas-cli via brew install faas-cli or curl -sSL https://get.openfaas.com | sudo sh.

Build and deploy

Build and deploy your stack using the following commands:

$ faas-cli -action build -f ./stack.yml
$ faas-cli -action push -f ./stack.yml (optional)
$ faas-cli -action deploy -f ./stack.yml

Test

Using curl, you can send an empty payload to the function to check-in:

$ curl localhost:8080/function/swarm_checkin -d ''

That's it. You're checked in!

You can hook this up with IFTTT to automatically check you in to places when you arrive there. Give it a shot!