About EraB2B
EraB2B is an outbound agency run by Louis Deslus. At any given time, it runs cold email for 15 to 25 clients. Each client gets at least 5 sending domains with 3 mailboxes on each, so 15 or more mailboxes per client, sized to the volume that client has bought. Every new client means new domains and new inboxes, so the setup work never really stops.
Before Mailpool
Louis has run outbound for a long time. Early on, he bought Google Workspace and Microsoft licenses by hand and ran his own SMTP servers. Those servers got harder and harder to keep alive, so he moved to Google Workspace and Outlook on his own setup, with an offshore team doing the work. Even well drilled, a new client took half a day. The offshore team made that cheaper, not faster. Later he moved to a competing provider, and setup got fast. The support was what wore thin.
Why EraB2B switched
Two things came together. Support at the competing provider kept getting worse, and a deliverability incident hit a client account. Louis moved to Mailpool, and what won him over was the support. Anyone who runs email infrastructure knows something will always break. So what matters is who answers. At Mailpool, the people who answer are deliverability experts, and they help him understand the problem, not just close the ticket.
EraB2B on Mailpool today
EraB2B has been on Mailpool since October 2025 and runs close to 700 inboxes today. Most are on Google Workspace, and the rest are split between Mailpool SMTP and Microsoft 365. A new client now takes minutes, with no offshore step. Louis orders domains and mailboxes through Mailpool’s API or MCP server, and they plug straight into PlusVibe, his sending tool.
Over a recent 14-day window, 5.16% of the prospects EraB2B contacted replied, and a third of those replies were positive. Louis is careful about what that shows. The numbers cover his whole client book, and infrastructure is one variable among several. What he credits Mailpool with is stability. He has stopped babysitting his setup, sees fewer deliverability incidents, and takes on more clients without growing the team.
Why three providers
For EraB2B, Google Workspace gets the best results right now, even when sending to Outlook and Microsoft recipients. Louis still keeps all three providers live and measured. If the numbers change, he already knows how the other two perform, and he can shift weight without rebuilding anything.
That’s the lesson for other agencies. Don’t let one provider stand between your clients and their pipeline. Run more than one, measure all of them, and work with people who can tell you why something broke.
