Smartlead is my go-to sequencer. Strong deliverability features, a full-featured API, AI agents for sales and reply handling, and volume-based pricing that actually makes sense for agencies running multiple clients. Most of the campaigns we run through Beanstalk use Smartlead for the sequencing layer, and the teams we work with at ScaledMail do too. They're now trusted by 100,000+ businesses, from agencies to Fortune 500 teams.
When you pair Smartlead with ScaledMail's managed infrastructure, you get a clean two-layer stack: Smartlead running the campaigns and AI workflows, ScaledMail running the inboxes underneath. Here's why that pairing works so well, and exactly how to set it up.
Who Smartlead Is For
Smartlead is built for teams that want AI-powered outbound workflows on top of a strong deliverability layer, paired with volume-based pricing instead of per-seat billing. The features that make it a strong sequencer:
- Four pricing tiers: Base (6K sends / 2K verified emails), Pro (90K / 30K), Smart (150K / 50K), and Prime (510K / 170K). Volume-based, not per-seat. That is the right model once your team grows. Annual billing comes with a discount off monthly rates.
- Built-in verified prospect emails: Every tier includes a bucket of verified emails each month, so you're not paying a separate verifier for every upload.
- AI Sales Agent and Reply Agent: Smartlead's newer AI workflows handle personalization and reply triage directly in the platform. For teams running lean, this consolidates two jobs that used to need separate tools.
- Unified master inbox: All replies across all campaigns and inboxes in one place.
- Strong API: One of the most complete APIs in the category. If you're integrating your sequencer into a broader GTM stack, Smartlead makes that workable.
- Native sender rotation: Distribute sends across connected inboxes automatically. Critical once you pass one or two mailboxes per campaign.
- Multi-client workspace management: Clean separation per client for agencies running multiple accounts.
Why the ScaledMail + Smartlead Pairing Works
The cleanest cold email stacks I see have one thing in common: the sequencer and the infrastructure are specialist tools, each focused on its own layer. Smartlead handles the send orchestration. ScaledMail handles the mailbox infrastructure. Neither tries to do the other's job.
Division of Labor
Smartlead schedules the sends, rotates across connected inboxes, runs the sequences, and captures replies. ScaledMail provisions the inboxes Smartlead sends through, configures SPF/DKIM/DMARC on every domain, keeps warmup running, and monitors mailbox health. Two layers, zero overlap.
Isolated Mailbox Infrastructure
ScaledMail provisions Google Workspace and Microsoft 365 accounts on isolated tenants. Your ESP reputation is entirely your own, not shared with other customers. That isolation matters because sender reputation within an ESP is what drives placement over the long term. Smartlead's sender rotation works beautifully on top of isolated infrastructure: you're distributing sends across inboxes whose reputation you control.
Aligned Support Philosophy
Smartlead's Slack support channel is one of the reasons agencies pick it over competitors. ScaledMail works the same way. Every customer gets a dedicated Slack channel with our US-based team. When something needs diagnosing (whether it's a sending issue in Smartlead or a deliverability issue on the infrastructure side), you're talking to humans who know the stack, on both sides.
ESP Diversification on the Inbox Layer
Smartlead is the sequencer. ScaledMail controls the ESP mix. We provision Google Workspace and Microsoft 365 across isolated tenants. When Google tightens filters in a given quarter, your Microsoft inboxes keep delivering. When Microsoft rolls out new filtering, Google picks up the slack. Smartlead connects to both via OAuth. You assign inboxes to campaigns and the sequencer handles the rest.
How the Stack Works Together
Clean division of responsibility:
- ScaledMail: Domain acquisition, DNS authentication (SPF, DKIM, DMARC), mailbox provisioning on Google Workspace and Microsoft 365, compatibility with 2:1 warmup ratio maintained permanently via your warmup tool, deliverability monitoring, blacklist remediation, domain rotation, pre-aged domain inventory.
- Smartlead: Campaign sequences, sender rotation, lead management, scheduling, reply detection and classification, unified master inbox, analytics, API integrations, multi-client workspaces.
Smartlead connects to your ScaledMail inboxes via OAuth. It sends through those inboxes. ScaledMail keeps them healthy, warmed, and properly authenticated. You run campaigns in Smartlead. We manage the infrastructure underneath.
Setup Process
Step 1: Spec Your Infrastructure
Book a call or use the infrastructure calculator. We need:
- Target daily cold email volume across all clients and campaigns
- Number of active Smartlead workspaces (one per client or one per internal campaign line)
- ESP preference (we recommend mixing Google Workspace and Microsoft 365)
- Launch timeline (pre-aged domains available for same-week launch)
Volume planning: 15-25 cold emails per inbox per day on Google Workspace, 5-10 per day on Microsoft 365. Every inbox maintains a 2:1 warmup ratio permanently. For every 1 cold email sent, 2 warmup emails run through your warmup tool. That ratio runs continuously, more than during initial warmup.
To send 1,000 cold emails per day: roughly 50-65 Google inboxes across 25-33 domains, plus a 20-30% rotation buffer. We'll give you exact numbers based on your targeting geography and volume pattern.
Step 2: We Build the Infrastructure
Our team handles the full build:
- Domain selection: .com preferred. No hyphens, no numbers, no spam trigger words. Every domain forwards to your main business website.
- DNS configuration: SPF, DKIM, and DMARC records configured and verified on every domain. DKIM propagation can take up to 48 hours. We monitor until it resolves correctly.
- Mailbox provisioning: Google Workspace and Microsoft 365 accounts provisioned on isolated tenant infrastructure.
- Warmup activation: ScaledMail is compatible with all warmup tools. Connect your warmup tool and maintain the 2:1 ratio from day one. Fresh domains run a 14-day warmup period. Pre-aged domains (30, 90, or 180 days old) are campaign-ready faster.
Standard 40-inbox build: 24-48 hours. You don't touch DNS. You don't log into GoDaddy or Namecheap. We deliver ready-to-use credentials.
Step 3: Connect to Smartlead
Once inboxes are warmed and deliverability is verified, connect them to Smartlead via OAuth:
- Navigate to Email Accounts → Add New
- Select Google or Microsoft as the connection type
- Authorize via OAuth. One-click for Google Workspace and Microsoft 365
- Set the daily sending limit to the number we specify for that inbox
- Assign inboxes to the appropriate workspace or campaign rotation
For agencies connecting 30+ inboxes, we export a structured CSV with all credentials. Smartlead supports bulk inbox import for large setups.
Step 4: Campaign Configuration in Smartlead
With ScaledMail inboxes connected:
- Daily limits: Match what ScaledMail specified per inbox. These numbers are calibrated to the 2:1 warmup ratio and ESP-specific safe zones.
- Sending window: 8am-6pm recipient timezone for B2B. Smartlead handles timezone detection, configure it correctly and let it work.
- Open tracking: Turn it off. Apple Privacy preloads content, making open data meaningless. Tracking pixels also trip spam filters. Track replies instead.
- Sequence length: 1-2 email touches, then 90 days dark. Most positive responses come from email #1. Longer sequences spike complaint rates.
- Sender rotation: Smartlead's native rotation spreads sends across your inbox pool automatically. Let it do its job.
Step 5: Bounce Rate Management
Target bounce rate under 1.5%. Before uploading leads to Smartlead, verify them. We recommend LeadMagic plus BounceBan for catch-all domains. If your bounce rate climbs above 1.5% in Smartlead's analytics, pause that campaign and re-verify the list before resuming.
Domain Rotation with Smartlead
We manage domain rotation on the infrastructure side using a 2-batch system:
- Batch A sends actively for 3 weeks
- Batch B rests (minimum 1 send per day to maintain warmup engagement)
- After 3 weeks, batches swap
In Smartlead, this means we periodically update which inboxes are in your active rotation. We handle the scheduling and notify you in Slack when batches swap. Your active inbox pool stays fresh without you managing it manually.
Domain longevity: high-engagement campaigns keep domains 12-18 months. Lower-engagement campaigns, we plan for replacement every 5 months. Isolated infrastructure removes one variable from that equation.
Where Smartlead + ScaledMail Fits Best
This stack works across a wide range of team sizes. The sweet spot:
- Agencies running multiple client campaigns where volume-based pricing beats per-seat billing
- Teams that want Smartlead's API for custom integrations into broader GTM systems
- Operations running 20+ inboxes where sender rotation and unified reply management become non-negotiable
- Teams that want managed infrastructure but prefer Smartlead's sequencer UX and pricing model
If you're starting out with cold email or running lower volume, a lighter sequencer pairing also works well. At higher end, agencies often graduate to EmailBison + ScaledMail for single-tenant sequencer isolation on top of isolated mailbox infrastructure.
What Agencies Running This Stack Tell Us
"I audibly said 'wow' within 24 hours of using ScaledMail. I was blown away by the speed of their execution and the thoroughness of their processes. Every detail is accounted for, and I've never had a more hands-off experience."
. Aaron Gusinov, CEO, LeadForce Solutions
"Best inbox provider out there. We've been using them for over half a year now, have spent many thousands of dollars with them, and are extremely happy customers. Stop looking for inboxes if you're looking and go with these guys."
. Tim Carden
"ScaledMail has saved us a ton of time buying domains and setting up inboxes, which we used to do manually in-house. Their team are very supportive, and the response time is perfect. Bonus points for end-to-end delivery with sequencer setup."
. Growth Labz
Frequently Asked Questions
Does ScaledMail's warmup work alongside Smartlead?
Yes. ScaledMail is compatible with all warmup tools, warmup is not included in ScaledMail but runs alongside it. Smartlead's sending layer doesn't interfere. Connect your warmup tool to your ScaledMail inboxes and maintain the 2:1 ratio continuously, independent of your Smartlead campaign sends.
How do I structure inbox-to-workspace assignment in Smartlead?
Clean separation per client or campaign type. Assign a dedicated inbox pool to each Smartlead workspace. ScaledMail can provision isolated batches per client so that one client's sending behavior doesn't affect another's inbox reputation. For agencies, this is the right architecture, full client isolation at the inbox level.
Can I keep my existing Smartlead workspace and just swap in ScaledMail inboxes?
Yes. Your sequences, lead lists, and analytics stay in Smartlead. We provision new inboxes (or transition existing ones where appropriate), configure DNS, and deliver credentials. You connect them in Smartlead's Email Accounts panel and start running campaigns through the new inbox pool.
How fast can I get ScaledMail inboxes live in Smartlead?
With pre-aged domains: 24-48 hours from order to campaigns running. With fresh domains: 14-day warmup period, then live. Most agencies keep a standing inventory of pre-aged inboxes for rapid client onboarding.
Do I need to disable Smartlead's open tracking?
Yes. Apple Mail Privacy Protection preloads email content, which means open rate data is fabricated. Every Apple Mail user shows as "opened" regardless of whether they opened the email. Tracking pixels also trip spam filters. Track replies only. Replies are the signal.
Does Smartlead's sender rotation work with ScaledMail inboxes?
Yes, and this is one of the reasons the pairing works so well. Smartlead's native rotation distributes sends across your connected inbox pool. Because ScaledMail provisions each inbox with its own isolated ESP reputation, rotation operates across a pool of independent senders. That is exactly what you want for deliverability.
Get Started
Running Smartlead or evaluating it for your stack? Book a call to spec your infrastructure, or build your custom package now.
Month-to-month. No annual lock-in. Pre-aged domains available for same-week launch.