# Heatmap

L2 order book heatmap reads.

`client.heatmap` reads historical L2 heatmap buckets and streams live buckets. It is a visualization/analytics surface, not an authoritative local order book.

```python
await client.wait_for_catalogs()

history = await client.heatmap.get(
    symbol="BTC-USDT",
    interval="1s",
    depth=50,
    limit=100,
    quantity_mode="close",
)
print(history.raw)
```

`symbol` or `symbol_id` is required. `start_time` / `end_time` accept `datetime`; `from_ts_sec` is an alternate cursor. Interval, depth, and quantity-mode labels are validated by the SDK.

```python
sub = await client.heatmap.subscribe_live(
    symbol="BTC-USDT",
    interval="1s",
)
async with sub:
    async for bucket in sub:
        print(bucket.raw)
        break
```

The live channel is public, but symbol-name use depends on a hydrated catalog. Responses are `ApiData` forward-compatible trees.

For executable price levels and sequence recovery use [Order book](https://testnet.polyester.com/docs/sdk/python/reference/order-book).