Identifiers

Most mistakes with the API come from mixing up ids. Here is what each one means.

Name	Looks like	What it is	Where to get it
LinkedIn profile id	`ACoAA…`	LinkedIn’s lasting id for a person. The safest way to name someone	`linkedin_profile_id` in most answers
Sales Navigator profile id	`ACwAA…`	The id Sales Navigator uses for the same person	`sales_nav_profile_id`
Slug	`john-smith`	The end of a LinkedIn URL: `linkedin.com/in/john-smith`	`slug`, or the profile’s URL
Conversation id	Text	One LinkedIn conversation	`conversation_id` from the conversation list
CRM contact id	Depends on your CRM	A contact in Attio, HubSpot or Affinity	`crm_contact_id`, or your CRM
CRM company id	Depends on your CRM	A company in your CRM	`crm_company_id`, or your CRM
LinkedIn account id	`4821`	Groovin’s id for a connected LinkedIn account	`org_linkedin_account_id`. You can usually leave it out
Import id	Text	One LinkedIn connections import	`import_id`

Which one to use

To reach someone, prefer ids in this order:

conversation_id when you already talk to them. It goes straight to the right thread, but a conversation can be a group.
linkedin_profile_id, which never changes.
crm_contact_id, when you start from your CRM.
linkedin_profile_slug as a last resort. A person can change their URL, and it can cost a live LinkedIn profile view.

Send CRM ids as text. HubSpot and Affinity ids look like numbers, but send "12345", not 12345. On crm/contacts/sync-toggle, numbers are silently dropped.
A slug is not an id. john-smith goes in slug or linkedin_profile_slug, never in linkedin_profile_id.
conversation_id and chat_id are the same thing. linkedin/chat-messages takes the first and answers with the second.
member_urn and connection_urn are LinkedIn’s internal references. You can ignore them. Use linkedin_profile_id instead.