foursquare Check-in Hack Utility

DEPRECATED: This utility has been discontinued as FourSquare has deprecated the v1 API that it relied on and has rolled out their new v2 API. The application source code is still here for anyone that is interested in modifying it for personal use.

The foursquare Check-in Hack utility is a Java UI re-implementation of Mayank Lahiri’s proof-of-concept 9-line Perl script used to initial Check-ins on foursquare at any location given it’s Venue ID and GPS coordinates.

Mayank first discovered the hole in foursquare’s API security while playing around the API and realized that a Check-in could be initiated for any location in the system and foursquare wouldn’t attempt to validate it (nor could it).


All download bundles include the library JAR, source code and Javadoc.


Included in the download are two scripts to make running the app easier:

  • run.bat (Windows)
    • Don’t forget to “chmod +x” to make the script executable!

Once the application is running, you need the VenueID and GPS coordinates for the location you want to check-in to; more information on how to find that information quickly and easily using the foursquare website and Google Maps is available here. You can also hover over the “?” icons in the interface to get tooltips to tell you where to get the values from.

For Quick Reference:

  • Venue ID: You can find this by opening the page on for the venue you want to check into, then looking at the URL in your browser (e.g. That last integer after the “venue/” part is the Venue ID. Just copy and paste it.

(Click to Enlarge)

  • Latitude & Longitude: Get the exact address off of for your venue and paste it into Google Maps. When the venue is centered, copy the link address for the Link link (linkity link link!) on the far right top of the Google Map (see screenshot above) and paste it anywhere you can look at it; for example into Notepad. Now, look for the sll argument (highlighted above in red) that value is the latitude and longitude separated by a comma; copy and paste those values into the program.


If you have Java installed on your computer correctly ( for easy install), you should be able to run the script without any issues. If Java is not installed correctly or maybe not accessible from the System PATH, you can manually run the app yourself using the following command line argument:

java -jar foursquare-checkin-hack.jar

If for some reason that doesn’t work and you need to run the specific class in the JAR that starts up the app, you can use this fallback launch command:

java -cp foursquare-checkin-hack.jar

(command is line-wrapped for readability, that command should be written all on one line).


Version 1.6

  • Added support for “shout” message (for Twitter or Facebook) to go along with your check-in.

Version 1.5

  • Added private check-in support. Check-in without notifying your friends. Thanks to Alex Yates for the suggestion!

Source Code

Source code is hosted at GitHub.

Feedback, Enhancements, Bug Reports, Questions

Please email me at, I would love to hear from you.


This software is licensed under the Apache 2 License.