---
title: "List topics"
method: GET
path: "/v1/topics"
tags: ["Topics", "tier:standard"]
---

# List topics

`GET /v1/topics`

## Request

- Base URL: `https://api.particle.pro`
- URL: `https://api.particle.pro/v1/topics`
- Auth: one of:
  - API key in header `X-API-Key`
  - HTTP bearer

Returns the hierarchical topic taxonomy. Use parent_id to navigate the tree, or q to find topics by name.

## Query parameters

- `limit` integer: Results per page
- `cursor` string: Opaque pagination cursor from previous response
- `parent_id` string: Get children of this topic. Accepts topic ID, ancestry slug, or ancestry path hash. Omit for top-level roots.
- `ancestry_path` string: Filter by exact ancestry path hash.
- `ancestry_path_prefix` string: Filter by ancestry path prefix (all descendants).
- `q` string: Find topics by name: exact names first, then names starting with q, then (when q has a word of 3 or more characters) names containing it, each ranked by story coverage. With parent_id or ancestry_path_prefix, searches that topic's descendants. Name search covers topics with at least 5 story clusters; browse with parent_id to reach the long tail.

## Response `200`

OK

- PageTopic
  - `cursor` string: Pass to next request for more results
  - `data` Topic[], nullable, required: List of results
    - `ancestry` string: Human-readable breadcrumb path (e.g. Business > Technology > AI)
    - `ancestry_path` string: Hash-based ancestry path for programmatic filtering
    - `episode_count` integer: Number of episodes in this podcast that cover this topic (only populated for /v1/podcasts/{id} topic lists)
    - `id` string, required: Unique identifier
    - `name` string, required: Topic name
    - `slug` string, required: Ancestry-based slug (e.g., technology/artificial-intelligence). Can be used as topic_id.
  - `has_more` boolean, required: Whether more results exist

## Other responses

- `402`: Payment Required. Read error_code. payment_required is the x402 path: either a keyless request being challenged — pay $0.01 in USDC per request (requirements in the PAYMENT-REQUIRED header) or send a pp_ API key — or a supplied payment that failed settlement (details in the PAYMENT-RESPONSE header; retry the same signature before signing a new one). See https://docs.particle.pro/x402. Any other code means the credential was accepted but does not cover this request (a plan or session gate such as premium_required or paid_plan_confirmation_required); its resolve says how to obtain access, and no payment header is sent.
- `default`: Error

---

[API](https://skmtc.dev/particle/apis/particle-api.md) · [All operations](https://skmtc.dev/particle/apis/particle-api/llms.txt) · [OpenAPI document](https://skmtc.dev/particle/apis/particle-api/revisions/416ba82ab9d7?raw)