Subfinder Passive Subdomain Enumeration

---
name: "Subfinder Fast Passive Subdomain Enumeration Tool"
slug: "subfinder-passive-subdomain-enumeration"
description: "Subfinder is a passive subdomain discovery tool by ProjectDiscovery that finds valid subdomains for websites using curated online sources. Optimized for speed and stealth, it integrates cleanly into security reconnaissance pipelines via stdin/stdout support."
github_stars: 13332
verification: "listed"
source: "https://github.com/projectdiscovery/subfinder"
author: "ProjectDiscovery"
publisher_type: "Open Source Project"
category: "Security & Verification"
framework: "Custom Agents"
tool_ecosystem:
  github_repo: "projectdiscovery/subfinder"
  github_stars: 13332
---

# Subfinder Fast Passive Subdomain Enumeration Tool

Subfinder is a passive subdomain discovery tool by ProjectDiscovery that finds valid subdomains for websites using curated online sources. Optimized for speed and stealth, it integrates cleanly into security reconnaissance pipelines via stdin/stdout support.

## Prerequisites

Go 1.21+

## Installation

No source-backed install or usage instructions could be extracted automatically. Review the upstream project before running this skill in a sensitive workflow.

- Source: https://github.com/projectdiscovery/subfinder

## Documentation

- https://docs.projectdiscovery.io/tools/subfinder/overview

## Source

- [Agent Skill Exchange](https://agentskillexchange.com/skills/subfinder-passive-subdomain-enumeration/)