# Data Overview

Coin API gives you access to three types of historical cryptocurrency market data. Each entity focuses on a different level of market detail — from aggregated candles to tick-level trades and quotes.

## Entities

| Entity                 | Best for                                                      |
| ---------------------- | ------------------------------------------------------------- |
| OHLCV Historical Data  | Price trend analysis, charting, backtesting strategies        |
| Trades Historical Data | Execution analysis, volume profiling, microstructure research |
| Quotes Historical Data | Spread analysis, liquidity research, bid/ask dynamics         |

## OHLCV Historical Data

#### Metrics

| Field           | Description                                                 |
| --------------- | ----------------------------------------------------------- |
| `price_open`    | Opening price at the start of the period                    |
| `price_high`    | Highest price during the period                             |
| `price_low`     | Lowest price during the period                              |
| `price_close`   | Closing price at the end of the period                      |
| `volume_traded` | Total volume of the base asset traded during the period     |
| `trades_count`  | Number of individual trades that occurred during the period |

#### Dimensions

| Field               | Description                                                 |
| ------------------- | ----------------------------------------------------------- |
| `symbol_id`         | The trading pair identifier (e.g., `BITSTAMP_SPOT_BTC_USD`) |
| `time_period_start` | Start timestamp of the candle period                        |
| `time_period_end`   | End timestamp of the candle period                          |
| `time_open`         | Exact timestamp of the first trade in the period            |
| `time_close`        | Exact timestamp of the last trade in the period             |

## Trades Historical Data

#### Metrics

| Field   | Description                     |
| ------- | ------------------------------- |
| `price` | Execution price of the trade    |
| `size`  | Volume of the base asset traded |

#### Dimensions

| Field           | Description                                      |
| --------------- | ------------------------------------------------ |
| `symbol_id`     | The trading pair identifier                      |
| `time_exchange` | Timestamp reported by the exchange               |
| `time_coinapi`  | Timestamp recorded by Coin API                   |
| `uuid`          | Unique identifier for the trade                  |
| `taker_side`    | Side of the taker (buy or sell, where available) |

## Quotes Historical Data

#### Metrics

| Field       | Description                                    |
| ----------- | ---------------------------------------------- |
| `ask_price` | Best ask (sell) price at the time of the quote |
| `ask_size`  | Volume available at the ask price              |
| `bid_price` | Best bid (buy) price at the time of the quote  |
| `bid_size`  | Volume available at the bid price              |

#### Dimensions

| Field           | Description                        |
| --------------- | ---------------------------------- |
| `symbol_id`     | The trading pair identifier        |
| `time_exchange` | Timestamp reported by the exchange |
| `time_coinapi`  | Timestamp recorded by Coin API     |

## Common metric combinations

* **OHLCV + volume\_traded + trades\_count** — identify high-activity periods where price moved on large volume
* **Quotes: ask\_price - bid\_price** — calculate spread over time to measure market liquidity
* **Trades: price + size** — compute volume-weighted average price (VWAP) across a session
* **OHLCV across multiple symbols** — use the **Append** transformation to combine candle data from different trading pairs for cross-asset comparison

## Use cases by role

{% tabs %}
{% tab title="Quant analysts" %}

* Pull OHLCV data for multiple symbols and use **Append** to build a unified price history table for backtesting
* Calculate rolling volatility and Sharpe ratios directly in BigQuery or a connected spreadsheet
* Use trades data to analyze execution slippage and fill quality
  {% endtab %}

{% tab title="Finance teams" %}

* Track portfolio asset prices over custom date ranges and export to Excel or Google Sheets for reporting
* Monitor bid/ask spreads from quotes data to assess liquidity risk for crypto holdings
* Schedule daily OHLCV pulls to maintain an up-to-date price ledger
  {% endtab %}

{% tab title="Researchers & AI users" %}

* Pipe OHLCV or trades data into ChatGPT, Claude, or Gemini to detect patterns and generate plain-language market summaries
* Use Perplexity or OpenClaw to ask questions directly over your historical trade data
* Combine multiple entities with **Join** to enrich trade records with contemporaneous quote data
  {% endtab %}
  {% endtabs %}

## Platform-specific notes

* Symbol IDs are exchange-specific — `BITSTAMP_SPOT_BTC_USD` and `COINBASE_SPOT_BTC_USD` are different symbols even for the same asset pair
* The time interval (period) parameter only applies to OHLCV data — trades and quotes return tick-level records
* Leaving the end date empty will pull data up to the current time, which is useful for scheduled incremental flows
* Very short time intervals (e.g., 1-second candles) over long date ranges can produce millions of rows — use the record limit parameter to control output size
* Coin API's free tier has rate limits and a cap on historical data depth; paid plans unlock full historical coverage