> ## Documentation Index
> Fetch the complete documentation index at: https://docs.0xarchive.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Data conventions

> 0xArchive REST data conventions: decimal strings vs numbers, UTC timestamps, the symbol/coin alias, and per-route type differences.

The REST payloads follow a few conventions consistently. Knowing them up front prevents the most common parsing bugs: precision loss on prices and type mismatches between routes.

## Decimal strings vs numbers

This is the one to get right. Some fields come back as **decimal strings**, others as **numbers**, and it varies by route:

| Shape          | Fields                                                                                                           | Why                                                                         |
| -------------- | ---------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------- |
| Decimal string | L2 `px`/`sz`, `mid_price`, `spread`, trade `price`/`size`/`fee`, `funding_rate`, `premium`, open interest values | Preserves precision; small rates and large sizes lose information as floats |
| Number         | L4 `price`/`size`, candle `open`/`high`/`low`/`close`/`volume`                                                   | These routes return numeric types directly                                  |

Keep decimal strings **as strings to the application edge**, then parse with a decimal library, not a float. Do not assume a field's type from another route: an order book's `px` is a string, but the same book's L4 `price` is a number. Check the type per route on the data-type page.

## Timestamps

Response timestamps are **ISO 8601 UTC** (for example `2026-06-05T13:53:33.971Z`). Request windows are different: market-state and order routes use **Unix milliseconds**. ISO 8601 strings are rejected by order routes — see [Parameters](/rest-api/parameters). Store timestamps in UTC and convert only at display.

## Symbol and the `coin` alias

`symbol` is the canonical field. `coin` appears in some payloads as a **deprecated alias** for the same value; prefer `symbol` and treat `coin` as legacy. Preserve the venue-specific symbol shape (plain perp, pair, builder prefix, outcome side) exactly as returned.

## HIP-4 prices are probabilities

On HIP-4 outcome markets, `mark_price` and `mid_price` are implied probabilities in the `[0, 1]` range, not USD. Label them as probability-like values in any chart, model, or export so downstream code does not treat them as asset prices.

## One envelope

Market-data routes wrap the result in `{ success, data, meta }`. Some auth, system, and data-quality routes return resource-specific bodies instead. See [Response envelope](/responses) for the full contract and the [field dictionary](/responses#field-dictionary) for individual fields.