mailhook

Local SMTP catcher + HTTP webhook inspector. One Go binary, zero external deps. Built for testing WSO2 IS pack flows that send mail (OTP, password reset) or POST to a notification endpoint (SMS, custom HTTP), but useful for any app that emits SMTP or webhooks.

• Catches outbound SMTP on 127.0.0.1:1025 (no auth, no TLS, local-only).
• Catches any HTTP method on 127.0.0.1:7790 — captures stay in memory.
• Optional per-method+path mock responses (Beeceptor-style).
• Web UI on 127.0.0.1:8091 and a JSON API + live NDJSON tail.
• ~6 MB binary, ~12 MB RSS, ~0% idle CPU.

Install

Requires Go 1.22+ (brew install go on macOS).

One-shot

go install github.com/PasinduYeshan/mailhook/cmd/mailhook@latest

Lands in $(go env GOPATH)/bin (usually ~/go/bin). Add it to PATH if not already:

export PATH="$(go env GOPATH)/bin:$PATH"

Verify:

mailhook help

From source

git clone https://github.com/PasinduYeshan/mailhook
cd mailhook
make install              # installs to $HOME/.local/bin

Uninstall

mailhook stop                                  # stop daemon if running
rm "$(go env GOPATH)/bin/mailhook"             # if installed via `go install`
# OR (if installed from source):
cd /path/to/mailhook && make uninstall

rm -rf "$HOME/.local/var/mailhook"             # optional: remove logs + pidfile

Quick start

mailhook start                     # background daemon
open http://127.0.0.1:8091/        # web UI

# Send mail to the catcher.
swaks --server localhost:1025 \
      --from is@test.local --to user@example.com \
      --header "Subject: OTP 482913" --body "Code: 482913"

# Or a webhook.
curl -X POST http://localhost:7790/sms/send -d '{"text":"hi"}'

# Inspect from CLI.
mailhook mail list
mailhook hook list
mailhook tail

mailhook stop                      # when done

Other commands

Command	What it does
mailhook start	start daemon in background
mailhook stop	stop daemon, reap orphan processes
mailhook restart	stop then start
mailhook status	show pid, RSS, CPU
mailhook logs	tail -f the daemon log
mailhook serve	run in the foreground
mailhook mail …	list / show / delete captured mail
mailhook hook …	list / show / delete captured webhook requests
mailhook rule …	add / list / update / delete mock-response rules
mailhook tail	live NDJSON stream of new captures

Full reference: see docs/cli.md.

Documentation

Topic	File
CLI reference	docs/cli.md
HTTP API	docs/api.md
Mock rules	docs/rules.md
WSO2 IS pack	docs/integration.md
Internals	docs/architecture.md
Agent skill	SKILL.md

License

MIT.