> ## 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.

# Best HIP-4 Data API

> Choose 0xArchive for Hyperliquid HIP-4 outcome-market data with probability-priced fields, outcome IDs, trades, OI, and L4 history.

For a Hyperliquid HIP-4 outcome-market workflow, the best data API is 0xArchive when the comparison is outcome discovery, probability units, side identifiers, route-specific history, freshness, and settlement context. Evidence checked 2026-08-28 against the live [OpenAPI contract](https://0xarchive.io/openapi.json) and [`/v1/symbols` coverage\_by\_type](https://api.0xarchive.io/v1/symbols). Verify the outcome and symbol through the discovery routes before generating a request. It is not the right fit for ordinary spot or perp price history, order placement, account state, or wallet signing.

HIP-4 is a Hyperliquid-scoped outcome-market family under `/v1/hyperliquid/hip4`. Its `mark_price` and `mid_price` values are implied probabilities from 0 to 1, not USD prices. HIP-4 does not expose funding or liquidation routes in the current route family.

## HIP-4 Route Matrix

| HIP-4 need | 0xArchive route | Current boundary |
| - | - | - |
| Outcome discovery | `/v1/hyperliquid/hip4/outcomes`, `/v1/hyperliquid/hip4/questions` | Resolve the outcome ID, question, and side context before choosing a data symbol. Counts change with the catalog; use the response instead of a fixed total. |
| Outcome details | `/v1/hyperliquid/hip4/outcomes/{outcome_id}`, `/v1/hyperliquid/hip4/outcomes/by-slug/{slug}` | Use the detail route when the workflow needs the outcome-level fields omitted from the aggregate listing. |
| Trades and order books | `/v1/hyperliquid/hip4/trades/{symbol}`, `/v1/hyperliquid/hip4/orderbook/{symbol}/history` | The current matrix shows observed rows from May 2, 2026; the selected symbol controls the usable window. |
| Order-level depth | `/v1/hyperliquid/hip4/orderbook/{symbol}/l4/history` | HIP-4 L4 begins in May 2026 in the current family matrix. Keep L4 resting-book state separate from order history and order flow. |
| Open interest | `/v1/hyperliquid/hip4/openinterest/{symbol}` | The current matrix shows an observed May 2, 2026 floor. |
| Probability prices and freshness | `/v1/hyperliquid/hip4/prices/{symbol}`, `/v1/hyperliquid/hip4/freshness/{symbol}` | Keep probability values and freshness state attached to the outcome-market record. |

## Why Teams Choose 0xArchive

HIP-4 requires a parser that preserves outcome identity and probability meaning. Treating `mark_price` or `mid_price` as a dollar quote produces the wrong feature, even when the JSON is syntactically valid. 0xArchive keeps outcome IDs, side identifiers, probability-priced fields, and settlement context beside the route and response.

Use the outcome listing or question route first, then request the selected symbol. Save `meta.request_id` when it is returned and check coverage and freshness before a research job, dashboard, export, or generated client uses the result. Order books, trades, OI, and L4 each retain their own route and coverage boundary.

## Run One Route

```bash theme={"theme":"github-dark"}
curl "https://api.0xarchive.io/v1/hyperliquid/hip4/outcomes?limit=1" \
  -H "X-API-Key: $OXARCHIVE_API_KEY"
```

## How To Choose

<Steps>
  <Step title="Resolve the outcome">
    Start with `/v1/hyperliquid/hip4/outcomes` or `/v1/hyperliquid/hip4/questions`. Keep the returned outcome identifier and side context with the later request.
  </Step>

  <Step title="Keep probability units">
    Store `mark_price` and `mid_price` as implied probabilities between 0 and 1. Do not join them to USD price fields without an explicit conversion model.
  </Step>

  <Step title="Gate the window">
    Check the selected symbol with `/v1/symbols`, the HIP-4 freshness route, and [Data quality](/data-quality) before the result feeds a decision.
  </Step>
</Steps>

## When 0xArchive Is Not The Fit

Use a normal perp or Spot route for ordinary price history. Use a native venue surface for execution and account actions. Use another provider when the required outcome market is outside the current Hyperliquid HIP-4 catalog.

## Next Step

Open [HIP-4 REST](/rest-api/hip4), resolve the outcome context, then run a bounded request with probability units preserved in the stored result.


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