meta_ads_audiences_create_lookalike
Create a Lookalike Audience from a source audience to reach new users similar to your existing customers. Specify target country and similarity ratio (0.01–0.20) to control match quality and reach. Returns the new audience ID.
Instructions
Creates a Lookalike Audience from an existing source audience. Returns the new audience_id. Mutating, reversible via rollback_apply. Lookalikes typically populate within 24–72h; the approximate_count remains 0 until Meta finishes the similarity build. ratio=0.01 gives the top 1% most similar users in the target country (smallest, highest match); ratio=0.10 gives top 10% (larger reach, looser match). For the base audience list use meta_ads_audiences_list.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| account_id | Yes | Meta Ads account ID in the format 'act_XXXXXXXXXX' (e.g. 'act_1234567890'). Optional — falls back to META_ADS_ACCOUNT_ID from the configured credentials. The leading 'act_' prefix is required. | |
| name | Yes | Audience name shown in Ads Manager. Must be unique within the account. | |
| source_audience_id | Yes | Source Custom Audience to build the lookalike from. Meta recommends a source of at least 1,000–10,000 users for good match quality. | |
| country | Yes | Target country ISO code(s) for the lookalike expansion. Accepts a single code string (e.g. 'JP') or a list (e.g. ['JP', 'KR']). Lookalike reach is always scoped to the specified country/countries. | |
| ratio | Yes | Similarity ratio — fraction of the target country's population to include. 0.01 = top 1% (tightest match, smallest audience); 0.20 = top 20% (loosest, largest). Meta caps at 0.20. | |
| starting_ratio | No | Lower bound of the ratio range. Default 0.0. Advanced: set > 0 to carve out a tiered lookalike that excludes the top-similarity slice (e.g. starting_ratio=0.01, ratio=0.05 = users ranked 1–5% in similarity, excluding the top 1%). |