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Cold email infrastructure

Cold Email Infrastructure at Scale

Build the sending infrastructure behind serious B2B outbound. We design and manage your sending domains, mailboxes, authentication, sequencer connections and infrastructure monitoring — so your sales team doesn't have to hold the system together manually.

Plan My Infrastructure Talk to Us
SENDING LAYER Monitoring
Prospect dataTarget accounts & contacts
Verified contactsEmail verification
Sending domainsSecondary outbound domains
SPFDKIMDMARCWarm-upMonitoringRotation
MailboxesDistributed sending accounts
SequencerSmartlead / Instantly / compatible tools
CRMReplies & sales workflow
POSO / OUTBOUND INFRAData → Send → Workflow

Why infrastructure matters

Cold email stops being a campaign problem when you start sending at scale.

A few inboxes are easy to manage. Once outbound volume grows, the underlying system gets more complicated: multiple domains, dozens of mailboxes, DNS records, warm-up, sending limits, sequencer connections, replacements and ongoing monitoring. When nobody owns that layer, sales teams end up operating fragile infrastructure that breaks at exactly the wrong time.

Too few sending domains

Concentrating your outbound on a small number of domains creates unnecessary dependency and risk.

Manual mailbox management

Provisioning, configuring, connecting and maintaining dozens of mailboxes quickly becomes operational work.

Bad or inconsistent DNS

SPF, DKIM and DMARC need to be correctly configured across the sending infrastructure.

No redundancy

When mailboxes or domains have problems, campaigns should not grind to a halt.

Disconnected tools

Domains, mailboxes, sequencers, Clay, CRM and sales workflows often become separate systems held together manually.

No clear owner

The sales team wants to run outbound. They usually do not want to become email infrastructure operators.

What Poso builds

The infrastructure behind your outbound.

We size the system around your outbound requirements and build the technical layer required to operate it.

1. Sending domain architecture

  • Secondary outbound domains
  • Domain portfolio planning
  • Separation from primary company email
  • Domain forwarding where appropriate
  • Capacity and redundancy planning

2. Mailbox infrastructure

  • Google Workspace and/or Microsoft 365 where appropriate
  • Mailbox provisioning
  • Mailbox distribution across sending domains
  • Naming conventions
  • Credential and ownership organization
  • Capacity planning

3. Email authentication

  • SPF configuration and validation
  • DKIM configuration and validation
  • DMARC configuration and validation
  • MX records where required
  • Related DNS configuration

4. Warm-up and ramp planning

  • Mailbox warm-up configuration
  • Conservative rollout
  • Gradual campaign activation
  • Capacity brought online in stages

5. Sequencer connection

  • Connect sending infrastructure to your outbound platform
  • Designed around tools such as Smartlead, Instantly, Lemlist or EmailBison
  • Compatible with other sending tools where appropriate

6. Monitoring and maintenance

  • Mailbox health monitoring
  • Domain health checks
  • Bounce monitoring
  • Capacity monitoring
  • Mailbox and domain replacement workflows
  • Reserve capacity where required

7. Provider diversification

  • Infrastructure that does not depend on one provider when volume and risk justify it
  • Reduced concentration of sending assets
  • Architecture aligned to your risk profile

8. GTM workflow connections

  • Clay and n8n workflow integration
  • Prospect enrichment and email verification
  • Suppression logic and CRM sync
  • Reply routing and campaign status updates
  • Reporting workflows

Complete sending layer

Not just mailboxes. The complete outbound sending layer.

Target accounts
Contact data + enrichment
Email verification
Sending infrastructure
DomainsMailboxesSPFDKIMDMARCWarm-upProvider mixMonitoring
Sequencer
Replies
CRM + sales workflow

Your team should be working prospects — not maintaining DNS records, replacing inboxes and manually wiring outbound tools together.

Scaling outbound

Scale by adding infrastructure — not by pushing a few inboxes harder.

Scaled outbound generally requires distributing sending across multiple mailboxes and domains instead of concentrating volume into a handful of accounts. Poso designs the infrastructure around your intended outreach volume, risk tolerance and existing stack.

Low volume

  • Few domains
  • Few mailboxes

Growing outbound

  • More domains
  • Distributed mailboxes
  • Redundancy

Scaled outbound

  • Larger sending pool
  • Provider diversification where appropriate
  • Reserve capacity
  • Ongoing monitoring

Poso difference

Infrastructure that connects to the rest of your GTM system.

Most email infrastructure problems don't exist in isolation. Contacts need to be sourced or enriched. Emails need to be verified. Prospects need to enter the right sequence. Replies need to reach the right person. CRM records need to reflect what happened. Poso can build the workflows around the sending infrastructure too.

Data Enrichment Verification Email infrastructure Sequencer CRM

One operating system instead of six disconnected tools.

Fit

Built for teams running real B2B outbound.

Good fit

  • Sales teams scaling outbound email
  • Companies already using Smartlead, Instantly, Clay, Apollo or similar tools
  • SDR teams that need more sending capacity
  • GTM teams with fragmented outbound infrastructure
  • Agencies managing infrastructure across multiple clients
  • Teams experiencing recurring mailbox or domain problems
  • Companies building a repeatable outbound operation

Not a fit

  • Consumer email marketing
  • Newsletter infrastructure
  • Transactional product email
  • Companies looking for spam blasting
  • People wanting to send huge volumes immediately from fresh infrastructure
  • Buyers simply looking for the cheapest possible mailbox
  • Businesses with no defined B2B sales motion

Scope

What we do and what we don't.

WE DO

  • Design outbound email infrastructure
  • Configure sending domains
  • Provision and connect mailboxes
  • Configure email authentication
  • Connect infrastructure to sequencers
  • Plan sending capacity
  • Monitor infrastructure
  • Build supporting workflows
  • Integrate relevant GTM tools

WE DON'T

  • Blast from your primary company domain
  • Promise guaranteed inbox placement
  • Sell a magical spam-proof setup
  • Recommend reckless sending volume
  • Build infrastructure without understanding the outbound use case
  • Pretend infrastructure can compensate for bad targeting, bad data or irrelevant messaging

Adjacent capability

Need the workflow before the inbox too?

Cold email infrastructure is only one part of outbound. Poso can also help clean and enrich prospect data, verify records, build Clay/n8n workflows and connect outbound activity back into your CRM.

Explore Sales Data & Workflow Infrastructure

FAQ

Common questions about cold email infrastructure.

What is cold email infrastructure?
Cold email infrastructure is the technical sending layer behind outbound email: sending domains, mailboxes, DNS authentication, warm-up, sequencer connections, sending capacity and ongoing infrastructure monitoring.
Why shouldn't we send cold email from our main company domain?
Outbound creates different reputation and operational risks from normal employee email. Using separate sending infrastructure helps isolate outbound activity from the domain your company relies on for normal business communication.
Do you provide the domains and mailboxes?
Poso can design the domain and mailbox architecture and manage provisioning as part of the implementation. Depending on the project, infrastructure may be provisioned through Google Workspace, Microsoft 365 or specialist third-party providers.
Can you work with our existing infrastructure?
Yes. We can review an existing setup, identify structural issues and either improve what is already there or rebuild the parts that need replacing.
Which cold email platforms can you work with?
The infrastructure can be designed around common outbound platforms such as Smartlead, Instantly, Lemlist, Apollo and compatible sending tools. The exact implementation depends on your existing stack.
Do you guarantee email deliverability?
No responsible infrastructure provider can guarantee that every cold email will reach the primary inbox. Deliverability is affected by infrastructure, list quality, sending behaviour, messaging, recipient engagement and mailbox-provider filtering. Our job is to build and operate the infrastructure correctly and reduce avoidable technical problems.
Can you help with prospect data as well?
Yes. Poso also works on sales data enrichment, email verification, Clay/n8n workflows, CRM hygiene and workflow automation. These can be connected to the sending infrastructure when required.
Can you manage the infrastructure after setup?
Yes. Ongoing monitoring, maintenance, capacity management and infrastructure remediation can be scoped as a managed service.

Get started

Building or scaling cold email?

Tell us how much outbound you want to run and what your current stack looks like. We'll help you design the infrastructure underneath it.

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