How to Map BUFF, Youpin, and C5Game Item IDs

GET /v1/schema exposes known catalog identifiers for BUFF, Youpin, and C5Game. Build the mapping around each row's exact market_hash_name, then attach whichever marketplace IDs are present.

The market name should remain your canonical identity. External catalog IDs are marketplace-specific attributes and can be unavailable.

Build one row per exact item#

Retain enough schema context to prevent accidental collisions:

• exact market_hash_name;
• item type and exterior;
• StatTrak and Souvenir row state;
• BUFF ID when present;
• Youpin ID when present;
• C5Game ID when present;
• schema generation_id.

Do not drop a row merely because one marketplace ID is null. That null means the schema does not currently expose a known identifier for that item on that marketplace.

Keep the mapping directional#

Support both lookups:

An integer from BUFF and the same integer from Youpin are unrelated namespaces. Never join external IDs without also naming the marketplace.

Handle variants explicitly#

Phase and specialty variants can have identities nested under a parent item. If a consumer needs them, retain the parent relationship and the variant label instead of flattening away that context.

Do not assign a parent marketplace ID to a child variant unless the schema explicitly provides that relationship. A missing phase-specific ID is not permission to invent one.

Validate before joining prices#

When a marketplace feed supplies both an ID and a market name, compare the name with the schema mapping. Quarantine mismatches rather than silently relabeling price data.

Also track schema generation_id with the mapping. The endpoint supports ETag validation, is available on all plans, and is cached for one hour. Refresh the mapping when the generation changes.

For the full schema surface, see get the CS2 item schema. When consuming public price data, continue joining on the normalized exact market name as described in current CS2 item prices.