How to add a user segment to a LaunchDarkly feature flag variation via API?

Question

I am trying to manage feature flag variations for groups of users via the LaunchDarkly API. My goal is to migrate users in groups, switching variations on a flag for specific segments, so I can change application behavior for certain users and gradually migrate them back and forth.

Here’s what I tried:

1. Create a segment

curl -X POST https://app.launchdarkly.com/api/v2/segments/someproject/someenv \
 -H "Authorization: api-XXXX" \
 -H "Content-Type: application/json; domain-model=launchdarkly.semanticpatch" \
 -d '{
       "name": "Group 1",
       "key": "group-1"
     }'

2. Add users to the segment

curl -X PATCH https://app.launchdarkly.com/api/v2/segments/someproject/someenv/group-1 \
 -H "Authorization: api-XXXX" \
 -H "Content-Type: application/json; domain-model=launchdarkly.semanticpatch" \
 -d '{
       "instructions": [{
         "kind": "addIncludedUsers",
         "values": [ "user-key-123abc", "user-key-456def" ]
       }]
     }'

3. Add the segment as a target to a flag variation

curl -X PATCH "https://app.launchdarkly.com/api/v2/flags/someproject/Migrations.someflag" \
 -H "Authorization: api-XXXX" \
 -H "Content-Type: application/json; domain-model=launchdarkly.semanticpatch" \
 -d '{
       "environmentKey": "someenv",
       "instructions": [{
         "kind": "addTargets",
         "variationId": "123123",
         "values": ["group-1"],
         "contextKind": "segment"
       }]
     }'

Problem:

I can create the segment and add users, but when I try to assign it to a flag variation, LaunchDarkly adds an individual user with key "italy-group-1" instead of applying the segment.

Goal:

I want to:

Define multiple user groups (segments)
Assign flag variations to segments, not individual users
Gradually migrate users to different variations and revert them if needed

How can I correctly add a segment to a feature flag variation via the API so that the flag recognizes all users in the segment?

Ilia · Accepted Answer · 2025-08-18 12:14:13Z

0

This one worked.

curl -X PATCH "https://app.launchdarkly.com/api/v2/flags/some_project/Migrations.someflag" \
      -H "Authorization: api-xxxx" \
      -H "Content-Type: application/json; domain-model=launchdarkly.semanticpatch" \
      -d '{
    "environmentKey": "mock",
    "instructions": [
      {
        "kind": "addRule",
          "variationId":"someid",
          "clauses": [
            {
              "op": "segmentMatch",
              "values": ["italy-group-1"],
              "contextKind": "user"
            }
          ]
        
      }
    ]
  }'

answered Aug 18 at 12:14

Ilia

3674 silver badges17 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

How to add a user segment to a LaunchDarkly feature flag variation via API?

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related