Endpoint
Prepare the seed cohort
Every request accepts exactly one seed source.
For CSV seeds, a LinkedIn profile URL column produces the most reliable identity matches. Recognized headers include
linkedin, linkedin url, linkedin profile, and profile url. Rows without a LinkedIn URL need a full name plus supporting identity data such as company, company domain, role, location, or education. Sixtyfour drops weak or ambiguous identity matches instead of guessing.
guidance adds requirements the seeds do not imply, such as "Only people in the United States with 8+ years of experience". The seeds define the audience.
Run a lookalike search
Submit the seed cohort, poll the dedicated status endpoint until the search completes, then pass itssearch_id to /search/query.
The start request resolves the seeds before it returns, which takes up to 90 seconds. Set your client timeout to at least 100 seconds.
Start response
The start endpoint returns HTTP 202 after resolving the seeds and launching the search.seed_diagnostics reports how many seeds Sixtyfour resolved. The search runs when at least one seed resolves.
Completed status
Poll every 10 seconds or slower, and stop on any status other thanrunning: completed, failed, cancelled, terminated, or timed_out.
filters, which has no fixed shape. Set include_filters=false to omit it.
total_results counts everyone who matches guidance, without the seeds; POST /search/query returns up to max_results of them. excluded_public_ids lists the seed people, who are left out of results, replays, and exports. While the search is running, the response carries progress_message. Fields without a value are omitted.
Page ranked results
Use the completedsearch_id for the first page:
raw_score. The seed people are excluded, so total_available is omitted:
Use a CSV seed cohort
A CSV seed file:handle_id as csv_resource_handle_id.
Export results
Pass the completed lookalikesearch_id to POST /search/export, poll the returned export task through GET /search/status/{task_id}, then download the generated CSV. See Export Search Results.