FilterLists API

⭐ Beginner's Pick Security / No Auth Required Beginner HTTPS
Free to Use Varies (check documentation)

Overview

FilterLists is a community-maintained directory API that catalogs hundreds of filter lists used by ad blockers and firewalls like uBlock Origin and Pi-hole. You can query it to get metadata about filter lists including their names, URLs, languages, and the software they target. It is useful for building ad-block management tools or staying current with the filter list ecosystem.

💡

Beginner Tip

FilterLists has no authentication — just call the REST API endpoints directly. Start with GET /api/v1/lists to retrieve all known filter lists and their metadata in one call.

Available Data

FilterLists data via REST API
JSON-formatted response data
Freely accessible without authentication

Example Response

JSON Response
{
  "status": "success",
  "data": {
    "result": "Data from FilterLists",
    "description": "Lists of filters for adblockers and firewalls",
    "timestamp": "2025-01-15T10:00:00Z"
  }
}

Field Reference

id Unique numeric identifier for the filter list.
name Human-readable name of the filter list.
description Brief explanation of what the filter list blocks or filters.
homeUrl Homepage URL where the filter list is officially maintained.
onDiskSizeKb Approximate file size of the filter list in kilobytes.
syntaxes List of filter syntaxes supported, such as AdBlock or hosts.

Implementation Example

const url = "https://filterlists.com/";
const response = await fetch(url);
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data);

What Can You Build?

Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.

Common Errors & Troubleshooting

404 Not Found The filter list ID specified in the URL does not exist.
First fetch all lists from /api/v1/lists to get valid IDs, then use those IDs for detail requests.
Slow response The full lists endpoint returns a large payload with hundreds of entries.
Cache the response locally and refresh it periodically rather than calling the API on every user request.
CORS error in browser Some endpoints may not support cross-origin requests from all domains.
Proxy the API call through your own backend server to avoid browser CORS restrictions.

Matrix Score Breakdown

🌐 Reachability 30/30
⚡ Speed 20/20
🔒 Security 15/15
🛠 Developer XP 15/20
✓ Reliability 7/15
Response Time 83ms

Fully tested on Apr 5, 2026

Technical Specifications

Auth No Auth
HTTPS REQUIRED
CORS UNKNOWN
Category Security
Difficulty Beginner
Verified: 2026-04-04

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