---
title: "Probability surface — horizon index"
method: GET
path: "/v1/surface/{metal}/expiries"
tags: ["surface"]
---

# Probability surface — horizon index

`GET /v1/surface/{metal}/expiries`

§5.3b — the live horizon index for one metal.

## Path parameters

- `metal` string, required

## Response `200`

Successful Response

- unknown

## Other responses

- `403` — plan_gated — requires the Pro tier or higher.
- `404` — unknown_metal, or no snapshot ever written for this metal.
- `422` — Validation Error

---

[API](https://skmtc.net/goldprice/apis/gold-api.md) · [All operations](https://skmtc.net/goldprice/apis/gold-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/goldprice/gold-api/revisions/5e6518098e6e/schema)