Per‑User Email Opt‑In vs Digest Email: Which to Enable for Sulu Notification Noise?

Direct Answer

For a large user base, enabling per‑user opt‑in is the most scalable way to cut email volume while still providing immediate alerts for critical events. A digest reduces SMTP load but introduces a delay that can hide time‑sensitive notifications. No zero‑code community plugin currently offers fine‑grained opt‑in in Sulu; you’ll need a custom subscriber or an admin UI extension.

Performance Implications

• Per‑user opt‑in: Each notification triggers a DB read of the user’s preference flag. The cost is proportional to the number of recipients per event, but the overall queue size stays small because only opted‑in users receive an email.
• Digest: Aggregation requires a persistent queue or cache entry per user, increasing memory usage and job count. The digest job runs once per interval, but the job’s payload grows with the total event volume, which can strain the queue worker and increase latency.

Timeliness Considerations

Immediate per‑event emails deliver alerts within milliseconds of the trigger, essential for publish failures or workflow rollbacks. Digest emails, even with a 15‑minute window, can miss the window for actions that require instant response. If your organization tolerates a short delay for non‑critical updates, a digest can be acceptable.

Community Support

Current Sulu documentation and popular bundles do not expose a per‑user email opt‑in setting out of the box. The common pattern is to implement a Symfony event subscriber that checks a custom preference table before firing the mailer. No widely used zero‑code plugin is known as of the last update.

Recommended Path for Your Setup

1. Identify the critical event types (e.g., publish failures, workflow status changes). Keep immediate email notifications for these only.
2. For informational events (e.g., content edits, scheduled publishes), implement a digest with a 15‑minute window.
3. Add a lightweight preference table (user_id, opt_in BOOLEAN) and a Symfony subscriber that filters emails based on this flag.
4. Configure the Symfony Mailer and Messenger to queue digest jobs, monitoring queue size and memory usage in your staging environment.
5. Iterate on the window length and critical event list based on user feedback and monitoring.

Missing Diagnostic Detail

To fine‑tune the recommendation, we need to know the proportion of critical versus informational events and the current daily event volume per active user. If the critical rate is high, a digest may not be suitable.