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The sync primitive: adds new contacts, updates existing ones, reactivates contacts the team removed, and never touches contacts who unsubscribed themselves. Safe to call repeatedly with the same data. Up to 500 entries per call; the public API’s PUT /email/lists/{id}/recipients takes 1000 and is the better fit for a scheduled job.

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Arguments

Send the user’s own id as external_id: matching happens on it first, so a later email change updates the same recipient instead of creating a second one. attributes is a flat map of up to 20 scalar values and replaces the stored map when provided.

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How entries are resolved

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Returns

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Errors

  • The call would push the list past 500 active recipients — nothing is written; split the batch or remove contacts first.
  • Unknown list id (or a list from another project).

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Example prompts

“Add these people from the CSV I pasted to the Customers list, with their names.”
“Sync our new signups from this week into the release-notes list, keyed by their user id.”