Cold outbound,
run like infrastructure.
Data you keep forever.
Sentinel sources and verifies leads, warms a fleet of mailboxes you control, sends campaigns from templates you can test, and sorts every reply. Every lead, send and dollar lands in your own database.
Works with
- Google Workspace
- Microsoft 365
- Zapmail
- SmartLead
- Apollo
- MillionVerifier
Product
Everything outbound needs,
in one place.
Most teams stitch together a sourcing tool, a verifier, a sequencer, a warmup service and a spreadsheet. Sentinel is the one system they were trying to build.
Campaigns and templates
Write templates once, version them, and test subject and body variants against each other. Every sender on your team runs their own campaigns from one library.
Mailbox fleet and warmup
Google Workspace and Microsoft mailboxes across isolated tenants and domains. Warmup ramps on measured deliverability, and one burned domain never takes the rest down.
Lead sourcing and verification
Search by role, industry and behavior, verify every address before it can be mailed, and keep suppression lists that a vendor can never silently ignore.
Reply inbox
Every reply lands in one queue, sorted by intent: interested, referral, not now, unsubscribe. Answer from the mailbox that sent, with the thread in view.
Spend, in one ledger
Every paid call to every vendor is a row with a dollar amount and a budget ceiling you can edit at runtime. No surprise invoices at month end.
Your own database
Leads, companies, sends, replies and costs live in a Postgres you own. Swap any vendor and the history stays. Export it, query it, train on it.
How it works
Five stages. No hand-offs.
Source
Find people by role, industry and behavior. Exclusions and do-not-contact lists run on your side, where you can see them.
Verify
Every address is checked before it can be mailed. Risky and bad verdicts are kept as data and never contacted.
Write
Each lead gets the template and variant that fits their segment. Subjects and bodies are tested against each other and the winner earns more volume.
Send
A warmed fleet sends inside per-mailbox daily caps, paced and randomized, skipping weekends and holidays.
Reply
Replies are sorted by intent and land in one inbox. Interested leads become follow-ups. Every outcome is recorded for the next campaign.
Integrations
Rent the tools. Keep the record.
Sentinel sits above the vendors and writes everything they do into your database. Change a sourcing tool or a sequencer and the leads, sends and replies you already have stay exactly where they were.
Google Workspace
Mailbox tenants and domains
Microsoft 365
Mailboxes through Zapmail
Zapmail
Managed inbox supply
SmartLead
Sequencing and warmup
Apollo
Lead sourcing
MillionVerifier
Email verification
Cloudflare
DNS and sending domains
Postgres
The warehouse you own
FAQ
Questions, answered.
Start sending from a fleet
you own.
Connect a tenant or provision managed mailboxes, load a template, and launch your first campaign today.