# ChangemakerStudios/Papercut-SMTP

Papercut SMTP -- The Simple Desktop Email Server

Repository: https://github.com/ChangemakerStudios/Papercut-SMTP
Canonical: https://ross.abutalabs.com/products/papercut-smtp
Language: C#
License: Apache-2.0
License Family: permissive
Topics: papercut, smtp-server, smtp, testing, server, wpf, email, development, development-tools
Last push: 2026-08-23T04:14:17+00:00

## Health v2 (maintenance only)
Score: 99/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 98, longevity 100
- inputs: {"age_days": 4025, "days_push": 10, "days_rel": 18, "gap_med": 20, "n_releases_24m": 8}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3325, forks 306 (observed 2026-08-28T04:07:56.393254+00:00)

## What it is
Papercut SMTP is a desktop application that runs a local SMTP server and displays every email your application sends, so nothing is ever delivered to real recipients. It offers a Windows desktop UI, a Dockerized web UI, and an optional MCP server for AI agents to inspect sent emails.

## Use cases
- catch emails sent during local development
- test email sending without delivering to real users
- inspect email HTML bodies, headers, and attachments
- run a fake SMTP server in Docker for CI tests
- let AI agents verify emails my app sends
- view emails from localhost:25 in a desktop app

## When to choose
- you need a zero-config local SMTP catcher for development or testing
- you want a desktop GUI or Docker web UI to view captured emails
- you want AI agents to assert on sent email content via MCP

## When to avoid
- you need to actually deliver email to real recipients
- you need a production SMTP relay with authentication and TLS
- you need a Linux-native desktop GUI (the desktop app is Windows-only)

## Facets
- artifact type: application
- maturity: active
- function: email, http-server, testing, mcp
- domain: developer-tools, email, testing
- platform: windows, cross-platform
- tags: smtp-server, email-testing, desktop-application, wpf, fake-smtp, email-viewer, ai-agents, docker

## Member repositories
- ChangemakerStudios/Papercut-SMTP (main) score 99

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:56.393254+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 2026-08-29T18:41:47.501917+00:00, confidence not recorded.
  - readme: https://github.com/ChangemakerStudios/Papercut-SMTP (fetched 2026-08-28T04:07:56.393254+00:00, sha d4d4ce88cb56)
- Data as of 2026-08-30T08:39:29.467469+00:00.