Sandbox mode
A starter mode that limits sending to verified addresses.
Some providers (most notably AWS SES) start every account in sandbox mode: you can only send to verified addresses until you request and receive production access. Plan for the approval lead time when launching.
reading this as growth and lifecycle teams
Growth work lives or dies on targeting and measurement. What matters is whether behavioral triggers can be built without engineering time, whether the event stream supports attribution past the open, and whether deliverability holds when broadcast volume shares a reputation with product email.
Applied to sandbox mode, that means weighing scheduling, event stream, deliverability, and operating track record ahead of the rest, against behavior-triggered journeys, broadcasts, and winback campaigns measured on revenue.