GlowBox

GlowBox works with any
SMTP email tool.

Keep your workflows, sequences, and automations. Swap the SMTP
layer to GlowBox so email routes through the healthiest mailbox
automatically, no UI change for your team.

GlowBox is deliverability infrastructure you enable through SMTP—your team keeps the same tools above it.

What GlowBox Is

GlowBox is an SMTP routing layer that sits underneath your

outbound tools and manages deliverability automatically.

You send emails like normal.
GlowBox decides how they get sent.

How Mailboxes Rotate

GlowBox does not "round-robin blindly."
Each send considers:

  • Mailbox Reputation
  • Provider Feedback
  • Recent Activity
  • Warmup Status
Thehealthiestmailbox sends the next email.

New vs High-Reputation Mailboxes

New mailboxes illustration

New
Mailboxes

  • Start with low volume
  • Gradually ramp up
  • Are protected from overload
High-reputation mailboxes illustration

High-Reputation
Mailboxes

  • Carry more volume
  • Absorb spikes safely
  • Shield newer inboxes

What Queueing
Protects Against

Emails wait just long enough to be sent
safely without breaking campaigns.

Sudden volume spikes iconSudden volume
Spikes
Provider throttling iconProvider
Throttling
Reputation drops iconReputation drops
from burst sending

Monitoring & Spam Rescue

GlowBox continuously monitors:

  • Send rates
  • Throttling signals
  • Delivery issues

If a mailbox degrades:

  • It's automatically cooled down
  • Volume shifts elsewhere
  • Campaigns continue running

Intelligent

Warmup isn't new, but GlowBox does it differently.

  • Warms mailboxes inside a pool
  • Uses real outbound traffic
  • Adjusts dynamically based on live reputation
Think Lemlist warmup + intelligent routing, not manual warmup babysitting.
Warmup Tools
SMTP Relays
GlowBox

= Limited in CRM: Typical warmup or SMTP add-ons are not your CRM's first-class, native email path—teams often juggle a parallel flow or workarounds. The checkmark in the GlowBox column means a layer built to work under the CRM. ✕ is not a match; ⚠ is only a partial match for true CRM-native flow.

Send-time routing
Reputation-aware
Queueing & caps
Works under CRM
Explains decisions

Make every HubSpot send count.

HubSpot handles the workflow. GlowBox handles deliverability and integrates seamlessly under HubSpot, intelligently sending outbound through healthy mailboxes so your reputation stays strong and your emails stay out of spam.

HubSpot integration with GlowBox
HighLevel integration with GlowBox

HighLevel sends. GlowBox delivers.

HighLevel is built for leverage. GlowBox protects inbox placement behind the scenes, routing email through healthy infraestructure so agencies can grow clients confidently without fighting spam folders or domain damage.

Frequently asked questions

What is GlowBox in one sentence?

GlowBox is outbound email infrastructure that connects to your tools through SMTP and routes each send through the healthiest mailbox in your pool.

Do I have to change my CRM or sequencer?

No. You keep your UI and workflows and only change SMTP credentials so mail flows through GlowBox.

What does GlowBox manage automatically?

Mailbox warmup, reputation signals, routing at send time, throttling aligned to limits, and ongoing monitoring so placement stays stable as volume changes.

Who is GlowBox for?

Teams and agencies running serious outbound volume who need predictable inbox placement without operating dozens of inboxes by hand.