---
title: "List interface standards"
method: GET
path: "/v1/interfaces"
tags: ["Compatibility"]
---

# List interface standards

`GET /v1/interfaces`

## Request

- Base URL: `https://api.gunspec.io`
- URL: `https://api.gunspec.io/v1/interfaces`
- Auth: one of:
  - API key in header `X-API-Key`
  - HTTP bearer

The controlled vocabulary of mount interfaces: rails, muzzle threads, optic footprints, stock and grip mounts, handguard mounts, magazine wells, side mounts, sight dovetails, bipod studs, sling points, trigger pockets and charging handles. Ids are kind-prefixed and stable.

Available on every plan. Requires an API key; Explorer keys receive a reduced field set.

## Query parameters

- `kind` string

## Headers

- `If-None-Match` string

## Response `200`

List interface standards

- object
  - `success` boolean, required: Always true on a successful response. Every error carries `false` and an `error` object instead.
  - `data` InterfaceStandard[], required: The response payload.
    - `id` string: Kind-prefixed standard id, e.g. `thread:1/2x28`. URL-encode it when addressing `/v1/interfaces/{id}/firearms`.
    - `kind` string: What sort of interface it is: `thread`, `rail`, `mag`, `stock_mount`, `optic_plate`.
    - `name` string: Display name, as the maker writes it.
    - `aliases` string[]: JSON array of alternative spellings of this standard id, as a string. Ids are never renamed; a new spelling becomes an alias.
    - `notes` string, nullable: Free-text notes that do not belong in a specific field.

## Other responses

- `304`: Your copy is current. No body is sent, and this response does not count toward the daily request allowance.
- `400`: Validation error
- `401`: Missing or invalid API key
- `403`: The credential is valid and the caller is not permitted. Three causes, none of which reissuing a key changes: the plan is below the endpoint's tier, the account is suspended, or the key is not attached to the thing being acted on, meaning a user account for `/v1/me` or a shop for `/v1/vendor`. Distinct from 401, which means the credential is missing, malformed or expired and a new one can work.
- `429`: A limit was reached. `RATE_LIMITED` is the per-minute limit: wait `Retry-After` seconds (a minute) and retry. `DAILY_CAP_EXCEEDED` is the plan's daily limit, per key: nothing will be served until the counters return to zero at midnight UTC. `MONTHLY_CAP_EXCEEDED` is the plan's monthly allowance, for the whole account: nothing will be served until midnight UTC on the first of next month, or until the plan changes. For both, `Retry-After` is the seconds until then and `error.resetsAt` says when as an instant. Calls made after a refusal are refused too and do not spend the month, and a free key that keeps calling is paused, so stop at the first one and resume at the reset.
- `500`: Internal server error

---

[API](https://skmtc.dev/gunspec/apis/gunspec-io-api.md) · [All operations](https://skmtc.dev/gunspec/apis/gunspec-io-api/llms.txt) · [OpenAPI document](https://skmtc.dev/gunspec/apis/gunspec-io-api/revisions/f2e974d8b05c?raw)