Using FourSquare's API to post location checkins to social media

What is this, 2016?

I like sharing my location with my pocket friends sometimes. If I'm in a cool bar that they know, perhaps they can recommend a drink. If they live nearby, maybe they want to come for dinner. Not everyone has FourSquare's SwarmApp, so it is handy to automatically share its updates with other people.

Of course, Swarm doesn't cross-post to social media because walled-gardens are the most profitable. This is my attempt to open it back up again.

Here's what they look like on BlueSky and Mastodon:

Checked in to Hamburger Fischmarkt, Große Elbstr. 9 (Fischmarkt), Germany Probably a *bit* early for a breakfast beer. See on Swarm

[image or embed]

— Terence Eden ( @edent.tel) 24 May 2026 at 07:45

Post by @Edent@mastodon.social

View on Mastodon

tl;dr

You can get the SwarmToSocial code from my GitLab.

At the moment, developers get 10,000 API calls for free each month. That's probably more than enough for most personal uses.

Documentation

I was pleasantly surprised that FourSquare's CheckIn documentation was fairly easy to use and understand.

Once you've signed up for a developer account you can create an OAuth app. That will generate a Client ID (ABC123), Client Secret (XYZ789), and you supply a Project URL.

Once done you can follow the Authentication documentation. Or just visit:

⧉ https://foursquare.com/oauth2/authenticate?
   client_id=ABC123
  &response_type=code
  &redirect_uri=https://example.com/

Sign in with your FourSquare account. It will redirect you to:

https://example.com/?code=456QWE

Use that code to construct the final URl:

⧉ https://foursquare.com/oauth2/access_token?
   client_id=ABC123
  &client_secret=XYZ789
  &grant_type=authorization_code
  &redirect_uri=http://example.com/
  &code=456QWE

That will respond with the Access Token:

⧉ JSON{
   "access_token":"asdfghjkl123456"
}

Hurrah! Posting a new checkin is relatively simple. POST to this URl with a header of accept: application/json

⧉ https://api.foursquare.com/v2/checkins/add?
   v=20260223
  &venueId=13600425
  &shout=This%20is%20a%20test
  &oauth_token=asdfghjkl123456

• v is, rather confusingly, a date. The versioning documentation has more details but, basically, set it to the date you deployed your app.
• venuId you'll need to find yourself (more on that later).
• shout is up to 140 characters (!) of URl encoded text.

That will send back rather a lot of JSON. Here are the important bits:

⧉ JSON{
  "meta": {
    "code": 200,
    "requestId": "123456789"
  },
  "response": {
    "checkin": {
      "id": "987654321",
      "createdAt": 1771843820,
      "type": "checkin",
      "visibility": "closeFriends",
      "shout": "This is a test of the API",
      "timeZoneOffset": -300,
      "editableUntil": 1771930220000,
      "user": {
        "id": "56367",
        "firstName": "Terence",
        "lastName": "Eden",
        "relationship": "self",
        "displayName": "Terence Eden"
      },
      "venue": {
        "id": "QWERTYUIOP",
        "name": "My Birthday Party!",
        "contact": {},
        "location": {
          "isFuzzed": true,
          "lat": 39.123456789,
          "lng": -84.987654321,
          "cc": "US",
          "city": "Cincinnati",
          "state": "KY",
          "country": "United States",
          "formattedAddress": [
            "Cincinnati, KY",
            "United States"
          ]
        }
      },
      "checkinShortUrl": "https://swarmapp.com/user/56367/checkin/987654321?s=wRZ7ByNfCW1DNrOIpsRcytPZelE"
    }
  }
}

For my purposes, the shout and checkinShortUrl are the most important. You can view a sample check in:

https://swarmapp.com/user/56367/checkin/699c34b55bad6b7fb1695544?s=LA7jCaAtH-s9CwSpgQrQdHrP5-8

Venue ID

If you're already using a service like Untappd you might be able to get the venue ID from that.

If not, FourSquare provides 100 million points of interest for free - although with questionable data quality.

Alternatively, you can search by location:

⧉ curl --request GET \
     --url 'https://places-api.foursquare.com/places/search?ll=51.123%2C0.123&radius=1000&sort=POPULARITY' \
     --header 'X-Places-Api-Version: 2025-06-17' \
     --header 'accept: application/json' \
     --header 'authorization: Bearer ABC123'

As far as I can see, the Bearer Token only exists on the documentation page. I couldn't find it in my developer console. Weird!

That gets you back:

⧉ JSON{
  "results": [
    {
      "fsq_place_id": "4be584ed2457a593ad8cab15",
      "latitude": 51.11783041264215,
      "longitude": 0.11219274871133413,
      "categories": [
        {
          "fsq_category_id": "4bf58dd8d48988d1fa941735",
          "name": "Farmers Market",
          "short_name": "Farmers Market",
          "plural_name": "Farmers Markets",
          "icon": {
            "prefix": "https://ss3.4sqi.net/img/categories_v2/shops/food_farmersmarket_",
            "suffix": ".png"
          }
        }
      ],
      "date_created": "2010-05-08",
      "date_refreshed": "2025-11-01",
      "distance": 970,
      "extended_location": {},
      "link": "/places/4be584ed2457a593ad8cab15",
      "location": {
        "address": "",
        "locality": "Hartfield",
        "region": "East Sussex",
        "postcode": "",
        "admin_region": "England",
        "country": "GB",
        "formatted_address": "Hartfield, East Sussex"
      },
      "name": "Perryhill Farm Shop",
      "placemaker_url": "https://foursquare.com/placemakers/review-place/4be584ed2457a593ad8cab15",
      "related_places": {},
      "social_media": {
        "twitter": ""
      },
      "tel": "",
      "website": "http://www.perryhillorchards.co.uk/index.php?sec=4"
    },
    {
      "fsq_place_id": "8896f77565e54a658585301d",
      "latitude": 51.11649,
      "longitude": 0.13131,
      "categories": [],
      "date_created": "2021-12-06",
      "date_refreshed": "2021-12-06",
      "distance": 909,
      "extended_location": {},
      "link": "/places/8896f77565e54a658585301d",
      "location": {
        "address": "Priory Park, Beech Green Lane",
        "locality": "Withyham",
        "region": "East Sussex",
        "postcode": "TN7 4DB",
        "admin_region": "England",
        "post_town": "Hartfield",
        "country": "GB",
        "formatted_address": "Priory Park, Beech Green Lane, Withyham, East Sussex, TN7 4DB"
      },
      "name": "Spectra Studios",
      "placemaker_url": "https://foursquare.com/placemakers/review-place/8896f77565e54a658585301d",
      "related_places": {},
      "social_media": {},
      "tel": "01892 487149"
    },
  ],
  "context": {
    "geo_bounds": {
      "circle": {
        "center": {
          "latitude": 51.123,
          "longitude": 0.1234
        },
        "radius": 1000
      }
    }
  }
}

You can manually check a place using the Placemaker site: https://foursquare.com/placemakers/review-place/64eca80f0398c97ab52298ec

Getting Existing Checkins

What if you've checked in to a place using the official Swarm app? How do you get your own recent checkin data?

Again, there is documentation on getting user checkins.

⧉ Bashcurl --request GET \
     --url 'https://api.foursquare.com/v2/users/self/checkins?v=20260223&limit=2&offset=0&oauth_token=asdfghjkl123456' \
     --header 'accept: application/json'

Where it says oauth_token it actually means the access_token.

The JSON that is returned is a bit verbose, so I've simplified it here:

⧉ JSON{
  "meta": {
    "code": 200,
    "requestId": "699c6505b488565a31e315e3"
  },
  "response": {
    "checkins": {
      "count": 2344,
      "items": [
        {
          "id": "699c34b55bad6b7fb1695544",
          "createdAt": 1771844789,
          "type": "checkin",
          "visibility": "closeFriends",
          "entities": [],
          "shout": "Testing the API using an Untappd FourSquare ID.",
          "timeZoneOffset": 0,
          "editableUntil": 1771931189000,
          "venue": {
            "id": "64eca80f0398c97ab52298ec",
            "name": "Abbey Wood Fossil Pit",
            "contact": {},
            "location": {
              "lat": 51.487514,
              "lng": 0.13048041,
              "postalCode": "SE2 0AX",
              "cc": "GB",
              "country": "United Kingdom",
              "formattedAddress": [
                "SE2 0AX"
              ]
            },
            "createdAt": 1693231119
          },
        },

Annoyingly, there's no checkinShortUrl which means it can't easily be shared.

For that, you'll need to use the get-checkin-details API:

⧉ Bashcurl --request GET \
     --url 'https://api.foursquare.com/v2/checkins/699c34b55bad6b7fb1695544?v=20250202&oauth_token=asdfghjkl123456' \
     --header 'accept: application/json'

Which will return this (truncated for brevity):

⧉ JSON{
  "meta": {
    "code": 200,
    "requestId": "699c67de5f5c0a0e8ab234db"
  },
  "response": {
    "checkin": {
      "id": "699c34b55bad6b7fb1695544",
      "createdAt": 1771844789,
      "type": "checkin",
      "shout": "Testing the API using an Untappd FourSquare ID.",
      "timeZoneOffset": 0,
      "checkinShortUrl": "https://swarmapp.com/user/56367/checkin/699c34b55bad6b7fb1695544?s=LA7jCaAtH-s9CwSpgQrQdHrP5-8",

Photos

If there's a photo with the checkin, it will be return in the JSON like this:

⧉ JSON{
  "response": {
    "checkin": {
      "photos": {
        "count": 1,
        "items": [
          {
            "id": "699f3a9f96799c05c0f16c9c",
            "createdAt": 1772042911,
            "prefix": "https://fastly.4sqi.net/img/general/",
            "suffix": "/56367_5VYox4Y-hs66wURVsYc1NLgOokfwBfcWhtKQrOlMdD8.jpg",
            "width": 1008,
            "height": 1344,

The URl for the image is prefix width x height suffix - in this case https://fastly.4sqi.net/img/general/1008x1344/56367_5VYox4Y-hs66wURVsYc1NLgOokfwBfcWhtKQrOlMdD8.jpg

You can adjust the width and height if you want a thumbnail or some other resolution.

If there's no photo, the count will be 0.

Putting it all together

Every 15 minutes, the SwarmToSocial code does the following:

1. Get the most recent checkin.
2. Read a local file to get the previously seen checkin ID.
3. If the checkin ID hasn't been seen before:
   1. Get the checkin details.
   2. Get the photo if it exists
   3. Post the checkin (plus photo) to Mastodon & BlueSky.
   4. Save the checkin ID to a file.

Enjoy!