Developer Sandbox
Log Only mode for CI. Redirect mode for staging. Free & Pro
Developer Sandbox: what it does
Every WordPress developer has the scar: staging fired real emails at real customers. NimblyMail’s sandbox catches every wp_mail() at the environment boundary. Redirect mode reroutes staging mail to your test inboxes with a safety banner injected; Log Only mode captures everything for CI without sending at all. Allowlist trusted addresses with regex or wildcards, and an admin-bar indicator makes the mode impossible to miss.
What you get with Developer Sandbox
Redirect mode
All staging email reroutes to your dev inboxes with a visible safety banner — original recipients preserved in headers.
Log Only mode
Capture every message for CI assertions without a single byte leaving the server.
Smart allowlists
Whitelist addresses or domains with wildcards and regex — your QA addresses always get through.
Admin-bar indicator
A persistent banner shows the active sandbox mode, so nobody mistakes staging for production.
Three steps, zero babysitting
Set the environment
Production, staging, or development — via wp-admin or a PHP constant in wp-config.php.
Pick a mode
Redirect to test inboxes, or Log Only for total capture. Allowlist the addresses that may send for real.
Deploy fearlessly
Code, migrate databases, and test checkout flows — customers never hear from staging again.
Developer Sandbox questions, answered
Catch-all tools like Mailtrap replace your mailer entirely. NimblyMail's sandbox wraps your real mailer: staging redirects to you, production sends normally, and the boundary is enforced by environment — not by remembering to toggle a plugin.
Yes. Environment and mode are settable via PHP constants, so staging and CI pipelines enforce the sandbox in wp-config.php — it can't be switched off from wp-admin.
It's rerouted to your configured redirect address with a safety banner and the original recipient in the headers — fully inspectable, never delivered to the real person.