# nmap/npcap

Nmap Project's Windows packet capture and transmission library

Repository: https://github.com/nmap/npcap
Canonical: https://ross.abutalabs.com/products/npcap
Homepage: https://npcap.com
Language: C
License: NOASSERTION
License Family: other
Topics: packet-capture, windows
Last push: 2026-05-28T16:23:18+00:00

## Health v2 (maintenance only)
Score: 83/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 84, release rhythm 71, longevity 100
- inputs: {"age_days": 4124, "days_push": 97, "days_rel": 119, "gap_med": 61.0, "n_releases_24m": 9}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3580, forks 592 (observed 2026-08-28T04:08:10.941785+00:00)

## What it is
Npcap is the Nmap Project's packet capture and injection library for Microsoft Windows, implementing the portable Pcap API via a custom NDIS kernel driver and a Windows build of libpcap. It is a modernized, actively maintained replacement for the discontinued WinPcap library, supporting loopback capture, raw 802.11 monitor mode, and raw packet sending.

## Use cases
- capture raw network packets on Windows
- sniff loopback traffic between local services
- capture Wi-Fi traffic in monitor mode
- inject raw packets from Windows applications
- build network analysis tools like Wireshark or Nmap on Windows
- port WinPcap-based software to a maintained library

## When to choose
- you need Pcap API packet capture or injection on Windows
- you need loopback or raw 802.11 capture that WinPcap lacks
- you are building or maintaining network tools (Nmap, Wireshark) on Windows
- you need an actively maintained WinPcap replacement with security fixes

## When to avoid
- you are on Linux or macOS, which already ship libpcap
- you need a permissively licensed library for redistribution without an OEM agreement
- you need userspace-only capture without installing a kernel driver

## Facets
- artifact type: library
- maturity: active
- function: networking, security, developer-tools
- domain: networking, security, developer-tools, windows
- platform: windows, c, cpp
- tags: packet-capture, packet-injection, libpcap, winpcap, kernel-driver, ndis, wireshark, nmap, loopback-capture, monitor-mode

## Member repositories
- nmap/npcap (main) score 83

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:10.941785+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:33:59.642141+00:00, confidence not recorded.
  - readme: https://github.com/nmap/npcap (fetched 2026-08-28T04:08:10.941785+00:00, sha 3e87ae552459)
  - homepage: https://npcap.com (fetched 2026-08-29T09:27:36.258442+00:00, sha fcf4b5e8edf6)
  - site_page: https://npcap.com/guide (fetched 2026-08-29T09:27:36.267894+00:00, sha c5f360e8c944)
  - site_page: https://npcap.com/guide/npcap-devguide.html (fetched 2026-08-29T09:27:36.276045+00:00, sha c942b98b8979)
  - site_page: https://npcap.com/changelog (fetched 2026-08-29T09:27:36.270267+00:00, sha 3b92f7c0c70c)
- Data as of 2026-08-30T08:39:29.467469+00:00.