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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.

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
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.