The official Mailgun for WordPress plugin doesn't log emails locally. It hooks wp_mail, hands the message to the Mailgun HTTP API or falls back to SMTP, and lets the cloud dashboard own the activity feed. The settings that actually decide deliverability live in wp_options under the mailgun key: API key, region (US or EU), useAPI flag, override-from address and name, and the open/click/HTML-only tracking trio. None of that surfaces across a multisite from the per-site settings page.

SleekView reads the option array on every blog, normalises the keys, and lays them out as columns. Region becomes a sortable string instead of a hidden dropdown, so a US-defaulted subsite that should be sending EU customer mail through the EU endpoint gets flagged in the same view as the rest of the network. Track-clicks lives at three values (yes, html-only, no) and only matters once you can compare it across blogs in one screen rather than clicking through twenty admin sessions.

For agencies inheriting a Mailgun-powered network, the most painful detail is the override-from. A custom from-address outside the sending domain quietly breaks SPF/DKIM alignment on whatever blog set it years ago. SleekView surfaces overrides as a column, flags entries whose domain doesn't match the configured Mailgun sending domain, and lets ops inline-edit the value. MAILGUN_* constants in wp-config.php are still respected and shown read-only.

Transactional email is the kind of system that fails in invisible, expensive ways. Mailgun for WordPress puts every consequential decision into a single option array on each blog: which datacenter your customer data crosses, whether your messages are tracked, whether the plugin sends through the modern HTTP API or the legacy SMTP fallback, and whether the from-address aligns with your verified sending domain. The native settings page handles one site at a time and hides the region as an unlabelled dropdown, so a multisite network ends up with subtle inconsistencies that nobody discovers until a deliverability dip or a GDPR audit.

The override-from problem is especially insidious: a marketing team sets news@yourbrand.io three years ago, the domain's DKIM record evolves, and now every email from that subsite quietly lands in spam without an obvious culprit. Mailgun's cloud dashboard records the bounce metrics but not the WP-side cause. SleekView pulls the per-site config into one comparable surface so the cause and the symptom can finally meet in the same place.