No rented lists
No selling generic exports or pretending a scraped list is validation.
The supply side of B2B outreach
Main Direct is an independent B2B outreach supply engine for audience filters, contact validation, liveness and deliverability infrastructure. It is not a list broker or volume-only agency.
About
Built around one constraint
Most outreach systems do not fail because someone wrote a bad sentence. They fail because the contact was irrelevant, stale, unreachable or sent through infrastructure that could not carry it.
NameMain Direct
FounderCosta D
FocusFilters · validated contact supply · deliverability
FormatSupply infrastructure
CoverageRemote · worldwide
LanguagesEnglish · Russian
How engagements work
01
Diagnose
Separate targeting, data, validation, infrastructure and message constraints.
02
Design
Define schemas, exit conditions, sending identities, guardrails and stop rules.
03
Build
Implement the pipeline, authentication and observability locally or in your stack.
04
Operate
Review signals, adjust filters and expand only when quality holds.
Working boundaries
Main Direct stays deliberately narrow.
No brand-domain cold send
Cold infrastructure is isolated from the domain carrying product, support and transactional mail.
No invented proof
No fabricated metrics, fake case studies or guaranteed-inbox claims.
Need the infrastructure, not another list?
Send the segment, target geographies, current data and sending setup. I’ll show whether the constraint is data quality, validation, deliverability or message architecture.
Request infrastructure review