> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tickdb.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Data Specification

> Symbol naming, timestamps, and K-line interval rules.

## Symbol Naming Rules

* Forex: `EURUSD`
* Metals: `XAUUSD`
* Indices: `SPX`
* US Stocks: `AAPL.US`
* HK Stocks: `700.HK`
* A-Shares: `000001.SZ` (Shenzhen), `600000.SH` (Shanghai)
* China Futures: `BU2609` (regular contract), `AP7777` (next continuous), `AP8888` (main continuous), `AP9999` (weighted continuous)
* Crypto: `BTCUSDT`

China futures use `market=CN` and `type=futures`. Regular contract codes change with the delivery month. Continuous symbols are intended for market tracking and do not represent deliverable contracts.

## Timestamp

* All timestamps are in **milliseconds (ms)**
* UTC-based