Duplicates users (same email and same userID)

Question

Hi, We are experiencing duplicates creation on intercom for the same userIds and emails, the example is below:I think that the problem is on SDK side or/and API calls to Intercom.For example, to update existing user we do a post request to search by email intercom id and update that contact, but it looks like sometimes (event if a user exists on Intercom ) by some reason we are not always getting intercom id back and then the script creates "a new contact"  (or it is something within SDK). The issue is that it is not a new contact and it should not work like that. Eventually these duplicated users go to "onboarding" series, but they are old and should not get any onboarding emails..What could be the issue and solve it? Maybe it is about API/SDK update?... Best,Anastasia

mateusz.leszkiewicz · Accepted Answer

Hi ​@Anastasia Markinaand ​@Inés B.Thank you for bringing upthis important issue about duplicate user creation. This is actually a known behavior in Intercom thatcan occur due to several technicalreasons. Let me explain what's happening and howto address it.WhyDuplicates Are CreatedIntercom's useridentification system works with multiple identifiers:email,user_id, andanonymous_id. Duplicates can becreated in these scenarios:1. Identifier MismatchIf you have anexisting user with an email but no user_id, and you makea request with both the same email AND anew user_id, Intercom maycreate a new user instead of updating the existing one. This is by design to prevent accidental data merging.2. RaceConditionsWhen multiple API calls happensimultaneously (which is common in high-traffic applications), two requests might try to create the same user at nearlythe same time. Thefirst request might not complete beforethe second one starts, causing both to thinkthe user doesn't exist.3. API Search FailuresSometimeswhen you search by email to get theIntercom ID, the API call might:Time outReturn an errorHavetemporary connectivity issuesFace rate limitingIn these cases, your script doesn't get the ID back even though the user exists, so it creates what it thinks is a"new" contact.4. SDKCaching IssuesSome SDKsimplement local caching that might not be immediatelyupdated when users are created through otherchannels, leading to stale data.Solutions& Best PracticesImmediate Fixes:ImplementRetry Logic: Add retry mechanisms with exponential backoff whensearching for usersUse RobustError Handling: Check for specificerror types and handle them appropriatelyImplement Proper Logging: Log all user creation attemptsto identify patternsAPI BestPractices:Use ConsistentIdentifiers: Always use the same combinationof identifiers (email+ user_id)Implement Idempotency: Make your user creation calls idempotent bychecking multiple timesHandle RateLimits: Implement proper rate limiting and retry logicUse Webhooks: Consider using Intercom webhooks to get notified ofuser events instead of polling// Pseudo-code for robust user handlingasync function findOrCreateUser(email, userId) { try {  // First attempt - search with retry logic  let user = await searchUserWithRetry(email, userId);  if (user) return user;   // If not found, attempt creation  return await createUserWithRetry(email, userId);  } catch (error) {  // Log and handle specific error types  handleUserCreationError(error, email, userId); }}Prevention Strategies:Regular Duplicate Cleanup: Implement a processto regularly identify and merge duplicatesMonitoring: Set up alerts for unusual duplicate creation patternsUserJourney Mapping: Reviewyour user onboarding flow to identify duplicatecreation pointsOnboarding Series IssueThe reasonduplicates are entering your onboarding series is likely because they're being treated as "new" users. You can prevent this by:Adding filtersto your onboarding series based on user creation date vs. account ageUsing custom attributes to track actualuser lifecycle stageImplementing duplicatedetection before triggering campaigns​@Anastasia Markina- I noticed you started a conversation withFin but didn't respond in time for it to reach ahuman agent. Did you seeFin's reply, and is everythingworking properly on your end?This is definitelya solvable issue, and with theright implementation patterns, you can significantly reduce duplicate creation. The key is implementing robust error handling and retry logic in your integration code.Hopethis helps! Let me know if you need clarificationon any of these points.It is best to reach out to us directly via Messenger in your workspaces so we can definitely investigate why duplicates are created in your particular situation.Although issue with user duplicates might seem similar inboth Ines and Anastasiaworkspacesthe root cause might be totally different in those cases.

Anastasia Markina · Answer

Hi,We are experiencing duplicates creation on intercom for the same userIds and emails, the example is below:I think that the problem is on SDK side or/and API calls to Intercom.For example, to update existing user we do a post request to search by email intercom id and update that contact, but it looks like sometimes (event if a user exists on Intercom ) by some reason we are not always getting intercom id back and then the script creates "a new contact" (or it is something within SDK). The issue is that it is not a new contact and it should not work like that. Eventually these duplicated users go to "onboarding" series, but they are old and should not get any onboarding emails..What could be the issue and solve it? Maybe it is about API/SDK update?...Best,Anastasiaexample:

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