Case Studies

ActiScale paid VAs to connect mailboxes to sequencers by hand across multiple providers. On InboxKit, new mailboxes route into Instantly, Smartlead, or Warmy automatically. Across roughly 1,600 mailboxes, admin time fell more than 50% and send volume per mailbox rose 30% at the same health rate.

Vectify had built outbound entirely on Google mailboxes, then failed twice trying to add Azure, once through outside providers and once with self-managed tenants. InboxKit's Azure tenants worked on the first real attempt. The same roughly $5,000 monthly spend now runs more than double the sending volume, with reply rates holding steady.

C17 Lab runs outbound infrastructure and campaigns for a roster of B2B clients. On previous providers, mailboxes burned out fast, forcing constant refresh cycles that delayed client campaigns. C17 Lab onboarded to InboxKit in a single day and has since scaled to 12,645 mailboxes across 5,510 domains, with leads up 1.5x.

Tim Yakubson had worked through most of the deliverability market before InboxKit, buying domains and mailboxes across providers, and even mailboxes given to him free, watching them burn out regardless. A recommendation led him to InboxKit's pre-warmed mailboxes, and he has stayed a customer since.

Most agencies treat client relationships as binary: pay the full retainer or walk. The Playbook Agency built a third option. By reselling InboxKit's infrastructure under their own brand, they gave budget-constrained clients somewhere to land instead of somewhere to leave, cutting churn 80% and growing infrastructure revenue 30%.

In early 2026, Cymate's primary email vendor failed and reply rates collapsed across dozens of client campaigns. Rather than wait it out, founder Wesley Hoang ran a head-to-head vendor test. InboxKit came out ahead 2.6x on positive replies — and within three months Cymate had rolled it across their entire client base.

TGP, the largest prospecting agency in Latin America, was bleeding ops hours stitching together domains, Google Workspace, and email creation across five separate vendors. On InboxKit, that whole chain collapsed into a few clicks — dropping client onboarding from hours to minutes without touching their 15.2% reply rate.

In late 2025, a Google mailbox crackdown ran through the email world and hit agencies hardest. Rather than chase the next cheap workaround, Jayson DeMers of OutreachBloom moved to InboxKit mid-crisis — and has run OutreachBloom's email infrastructure on it ever since, at an 11.5% reply rate and a 0.6% bounce rate.

A multi-client GTM agency transformed manual mailbox setup into a fully automated, self-service operation. In six months on InboxKit, Anevo Marketing went from zero to 4,361 mailboxes under their own control and cut client setup time from one to two weeks down to one to two hours.

Managing 100+ client campaigns at scale meant abandoning manual infrastructure work. InboxKit's automation became the only way forward — automated DNS (zero manual hours), domain isolation, zero suspensions, and a 17% average reply rate.