# Polymarket Websocket Schema Observed In Checkpoint 10B

This document summarizes observed public market websocket message shapes from the bounded 10B BTC sample. It does not include full raw payload dumps; raw payloads remain in the gzip JSONL sample files.

## Observed Event Types

### best_bid_ask

Count: `338`

Observed top-level fields: `asset_id, best_ask, best_bid, event_type, market, spread, timestamp`

Best quote summary; counted but not applied to level maps.

### book

Count: `314`

Observed top-level fields: `asks, asset_id, bids, event_type, hash, last_trade_price, market, tick_size, timestamp`

Nested level/change fields: `price, size`

Full per-token book snapshot used to initialize or replace local state.

### last_trade_price

Count: `155`

Observed top-level fields: `asset_id, event_type, fee_rate_bps, market, price, side, size, timestamp, transaction_hash`

Trade print summary; counted but not applied to level maps.

### new_market

Count: `1`

Observed top-level fields: `active, assets_ids, clob_token_ids, condition_id, description, event_message, event_type, fee_schedule, fees_enabled, game_start_time, group_item_title, id, line, market, order_price_min_tick_size, outcomes, question, slug, sports_market_type, tags, taker_base_fee, timestamp`

Market metadata broadcast; preserved and counted but unrelated to selected BTC token state in this sample.

### price_change

Count: `7771`

Observed top-level fields: `event_type, market, price_changes, timestamp`

Nested level/change fields: `asset_id, best_ask, best_bid, hash, price, side, size`

Incremental price/size updates applied after a token has an initialized book.