imap-idle-watcher

name

imap-idle-watcher

description

Real-time email monitoring using IMAP IDLE — no OAuth, no token expiration. Sets up a persistent connection to any IMAP server (Gmail, Outlook, Yahoo, etc.) and triggers a user-defined command instantly when new email arrives. Runs as a systemd service with auto-reconnect. Use when: (1) setting up email-triggered automation, (2) watching an inbox for new messages in real-time, (3) replacing OAuth-based email polling that keeps breaking due to token expiry, (4) building email-to-webhook or email-to-script pipelines. NOT for: sending email, reading/parsing email bodies, or non-Linux systems without systemd.

IMAP IDLE Watcher

Real-time email watcher. Uses IMAP IDLE (server push) instead of polling. App passwords instead of OAuth — no token expiry, no re-auth.

Quick Start

Interactive

bash scripts/setup_service.sh

Prompts for email, detects provider, gives app password link, tests connection, installs service.

Non-interactive

bash scripts/setup_service.sh \
  --account "[e-mail]" \
  --password "xxxx xxxx xxxx xxxx" \
  --command "python3 /path/to/handler.py" \
  --service-name my-watcher

Test connection only

bash scripts/setup_service.sh --test --account "[e-mail]" --password "xxxx"

Configuration (env vars)

Variable	Default	Description
IMAP_ACCOUNT	(required)	Email address
IMAP_PASSWORD	(required)	App password
IMAP_HOST	imap.gmail.com	IMAP server (auto-detected from email)
IMAP_PORT	993	IMAP port
IMAP_FOLDER	INBOX	Folder to watch
ON_NEW_MAIL_CMD	(optional)	Shell command to run on new mail
FILTER_FROM	(optional)	Only trigger for these senders (comma-separated, substring match)
FILTER_SUBJECT	(optional)	Only trigger for these subjects (comma-separated, substring match)
IDLE_TIMEOUT	1200	Seconds before IDLE renewal (max 1740)
DEBOUNCE_SECONDS	10	Min seconds between command runs

Filtering

Only process emails matching specific senders or subjects:

FILTER_FROM=paypal.com,stripe.com      # from contains either (OR)
FILTER_SUBJECT=payment,invoice         # subject contains either (OR)

• Case-insensitive substring match
• Both FROM and SUBJECT must match if both set (AND)
• Within each filter, any value matches (OR)
• No filter set = process all emails

Writing a Handler

The agent should write a handler script based on the user's intent. The daemon passes email metadata as env vars:

Variable	Example
MAIL_FROM	John Doe <[e-mail]>
MAIL_SUBJECT	Your order has shipped
MAIL_DATE	Mon, 17 Mar 2026 10:30:00 +0700
MAIL_UID	12345

Workflow

1. User describes what they want (e.g. "watch my inbox, summarize new emails")
2. Agent writes a handler script (Python/Bash) that reads the env vars and does what the user asked
3. Agent saves it somewhere persistent (e.g. ~/email-handler.py)
4. Agent runs setup_service.sh with --command "python3 ~/email-handler.py"

Example: user says "notify me about new emails"

Agent writes ~/email-handler.py:

#!/usr/bin/env python3
import os
print(f"New mail from {os.environ.get('MAIL_FROM', '?')}: {os.environ.get('MAIL_SUBJECT', '?')}")

Then wires it up:

bash scripts/setup_service.sh --account "[e-mail]" --password "xxxx" \
  --command "python3 ~/email-handler.py"

The handler is the agent's job — adapt it to whatever the user needs.

How It Works

1. Connects to IMAP server with app password (SSL)
2. Enters IDLE mode — server holds connection open
3. Server pushes notification when new mail arrives (instant, no polling)
4. Daemon runs ON_NEW_MAIL_CMD with email metadata as env vars (MAIL_FROM, MAIL_SUBJECT, MAIL_DATE, MAIL_UID)
5. Returns to IDLE. Renews every 20 min per RFC 2177.
6. Auto-reconnects on disconnect (backoff: 5s → 10s → 30s → 60s → 120s)

Service Management

systemctl status <service-name>
journalctl -u <service-name> -f
systemctl restart <service-name>
systemctl stop <service-name>

Uninstall

bash scripts/setup_service.sh --uninstall --service-name <service-name>

Provider Setup Guides

• Gmail: see references/gmail.md
• Outlook: see references/outlook.md
• Yahoo: see references/yahoo.md

Troubleshooting

See references/troubleshooting.md for common errors and fixes.