Inbox warmup
for agencies.
Email warmup for agencies running 5-50 client domains across Instantly, Smartlead, or lemlist. Multi-tenant separation, per-tenant Google OAuth, bulk SMTP import, and pricing that leaves you margin instead of taking it.
What goes wrong, specifically.
Multi-tenant management is an afterthought.
Most warmup tools treat every workspace as a single business. As an agency you are not one business — you are 15. Each client has their own domains, their own SDRs, their own deliverability concerns, and at some point their own auditor asking where their data sits. Spreadsheets named client-warmup-march-final-v3 are not multi-tenancy. You end up logging into separate accounts per client, paying a per-seat fee fifteen times, and hoping nobody clicks the wrong dropdown.
Multiple Google Workspaces, multiple OAuth screens.
Connecting client mailboxes via OAuth gets messy fast. If the warmup vendor uses their own Google Cloud project, every client sees a consent screen from a brand they have never heard of, asking for inbox access. Half of them bail. The other half tickets your support inbox. And when Google revokes the shared project for hitting a quota, your entire book of business goes dark. Agencies need their own GCP project per tenant — and most vendors flat out do not allow it.
Pricing eats your margin.
Per-mailbox pricing at $20+/mo across 50-100 mailboxes is $1,000-$2,000/mo before you have done a thing. That comes straight out of the retainer your clients pay. Agency-tier pricing is supposed to fix this, but most vendors gate it behind a sales call and price it like you are an enterprise. The result: cold-email agencies either eat 30% of revenue on tooling or quietly skip warmup entirely and hope.
Three things that matter.
Real multi-tenant management.
One agency login, scoped tenants per client. Each tenant has its own mailbox list, its own template library, its own placement scores, and its own audit log. You can grant a client read-only access to their tenant without exposing the rest of your book. Switching between tenants takes one keystroke.
Bulk SMTP import, per-tenant OAuth.
Drop in a 1,000-row CSV of SMTP/IMAP credentials and NeverSpam validates each one, runs an immediate placement probe, and starts the ramp. For Gmail/Workspace clients, the Agency tier lets you connect your own Google Cloud project per tenant — the consent screen carries your agency brand, not ours.
Agency-margin pricing, no sales call.
$499/mo for 50 mailboxes works out to roughly $10/mailbox — about a third of what most vendors charge at this volume. Self-serve signup, month-to-month, cancel any time. The savings against typical agency tooling pay for the year by month two.
How agencies use NeverSpam.
A typical agency runs cold outbound for 10-20 clients, each with 2-5 sending domains and 3-6 mailboxes per domain. That is 60-300 mailboxes total. Inside NeverSpam, each client is a tenant. The agency owner sees a top-level dashboard showing every tenant’s aggregate inbox-placement score; account managers see only the tenants they own.
When a new client signs, the AM imports the mailbox CSV, then drops the exact Instantly campaign template into NeverSpam. Warmup ramps over 10-14 days against our 100K+ seed inbox pool. By day 14 the placement scores tell you which mailboxes are inbox-ready; the Instantly tag automation then handles rotation automatically — if mailbox 17 starts landing in promotions, NeverSpam tags it Standby in Instantly so the campaign pulls it out of active rotation until it recovers.
Read more on the workflow in our template-based warmup guide or check the Instantly integration docs.
- 01Create a tenant per client. Set the GCP project ID if using your own.
- 02Bulk import sending accounts via CSV or per-mailbox OAuth.
- 03Paste the client’s real Instantly template — subject, body, links, CTAs.
- 04Connect Instantly via API key. Tag automation goes live within 5 minutes.
- 05Export the weekly placement-test PDF and drop it in your client report.
↳ Composite scenarios. Real customer testimonials forthcoming.
“We onboard a new client in about 45 minutes now. CSV in, tenant up, OAuth on our own GCP project so the client sees our brand on the consent screen. The bit that sold me was the Instantly tag rotation — before NeverSpam we had a VA checking placement scores every Monday and manually flipping tags. That role is now a Slack channel.”
“The pricing was honestly the reason we switched. We had 80 mailboxes on a competitor at $24 each — call it $1,900/mo. NeverSpam is $499 for the Agency tier and we ate two more clients of margin in the first quarter. Warmup quality has been at least as good; placement scores hold week to week.”
“What I needed was someone to warm the actual template my clients send, not generic synthetic copy. When you are running 12 different verticals — SaaS, fintech, recruiting — the templates look nothing alike, and warming generic conversations on the same mailbox just trains the wrong reputation. NeverSpam was the only one doing this.”
Plans that fit.
Most agencies start on Agency at $499/mo for 50 mailboxes — about $10/mailbox/mo, comfortable margin against the $30-60/mailbox most clients pay. If you are running fewer than 15 mailboxes total, Pro at $149/mo is the better starting point.
See full pricingQuestions, answered.
What is the best email warmup tool for agencies?
For agencies running cold-email campaigns across multiple client domains, the right warmup tool needs three things: multi-tenant separation so one client cannot see another, per-tenant Google OAuth so consent screens carry the client brand, and bulk import so onboarding a new client does not take a full day. NeverSpam was built around that workflow. Most warmup vendors treat agencies as a single workspace with extra seats — fine until a client asks where their data lives.
How many sending accounts can one agency manage?
The Agency tier covers 50 sending accounts at $499/mo. Most agencies running 10-20 clients with 2-4 mailboxes each fit comfortably in that envelope. If you are running a larger book, we have a custom tier with bulk SMTP import that handles 1,000+ rows in a single CSV. Each mailbox gets its own placement score and Instantly tag automation regardless of which client tenant it belongs to.
Can my clients see their own warmup data?
Yes. Each tenant has a scoped dashboard you can grant client access to, showing only that client's sending accounts, inbox-placement scores, and ramp progress. White-label is on the roadmap for late 2026. For now most agencies share weekly screenshots or export the placement-test PDF to attach to their reporting decks.
Does NeverSpam integrate with Instantly for agencies?
Yes — our Instantly integration is the most-used part of the product for agencies. NeverSpam reads inbox placement weekly and automatically rotates Instantly tags (Active, Standby, Bad, Delayed) so your campaigns only ever send from mailboxes that are landing in inbox. For an agency running 200 mailboxes across 15 clients this is the difference between a stable Monday and a stack of Slack pings from account managers.
How does pricing work when I want to bill clients separately?
NeverSpam bills you, the agency, on one card. Most agencies mark up the per-mailbox cost into their retainer — the Agency tier works out to roughly $10/mailbox/mo at 50 mailboxes, leaving comfortable margin against the $30-60/mailbox most clients expect to pay. Tenant-level invoicing is on the roadmap but most agencies prefer the current single-bill model.
Do I have to use my own Google Cloud project for OAuth?
You can, and on the Agency tier we strongly recommend it. Bringing your own GCP project means the OAuth consent screen carries your agency name, the verification (and rate limits) live in your account, and clients are connecting their Gmail to you rather than to a third-party brand they have never heard of. We document the GCP setup in 12 steps; it takes about 40 minutes the first time and zero minutes thereafter.
What happens to warmup if a client churns mid-month?
You disconnect their mailboxes from the agency tenant; warmup stops immediately on those accounts and the slots free up for the next client. Billing rolls month-to-month so churn does not stick you with paid-for capacity. The client keeps their domain reputation — reputation lives on the mailbox, not in NeverSpam.