# Public trades

Public trade tape reads and subscribe via market data.

Public prints for a spot market live on `client.market_data` (not `client.trades`, which is your private fills). No authentication is required. Call `await client.wait_for_catalogs()` first; quantity decoding fails closed when the market scale is unavailable.

## Methods

| Method             | Summary                                       |
| ------------------ | --------------------------------------------- |
| `get_trades`       | Recent public trades (paginated by match id). |
| `subscribe_trades` | Live public tape for one symbol.              |

### Get trades

```python
result = await client.market_data.get_trades(symbol="BTC-USDT", limit=20)
for t in result.trades:
    print(t.match_id, t.is_buy, t.price, t.qty, t.ts_ns)

# Continue from a match id cursor when present
if result.next_match_id:
    more = await client.market_data.get_trades(
        symbol="BTC-USDT",
        limit=20,
        from_match_id=int(result.next_match_id),
    )
```

| Field                  | Notes           |
| ---------------------- | --------------- |
| `symbol` / `symbol_id` | One required    |
| `limit`                | Default `100`   |
| `from_match_id`        | Optional cursor |

### Subscribe trades

Handshake completes before return. Consume with `async for`.

```python
subscription = await client.market_data.subscribe_trades(symbol="BTC-USDT")
async with subscription:
    async for trade in subscription:
        print(trade.price, trade.qty, trade.is_buy)
        break
```

## MarketTrade shape

`symbol_id`, `match_id`, `is_buy`, `price`, `qty`, `ts_ns`. Result wrapper: `MarketTradesResult(trades, next_match_id)`.

`is_buy` is a `bool` from the wire `is_buy` / `isBuy` field: `True` when the aggressor (taker) side is buy, `False` when the aggressor is sell. Python does not decode a separate `side` string on `MarketTrade` (unlike Rust/Go).

REST and realtime attach the same hydrated catalog scale to `qty`. The SDK does not decode public trade quantities using a guessed scale.

## Related

- [User trades](https://testnet.polyester.com/docs/sdk/python/reference/trades) for your private fills
- [Market data guide](https://testnet.polyester.com/docs/sdk/python/guides/market-data)
- [Streaming](https://testnet.polyester.com/docs/sdk/python/guides/streaming)