Sequenced emails to contacts you already have is genuinely buildable. A searchable database of other companies' verified contacts — Apollo's actual product — is licensed data, not a build.
Borderline
Effort: a weekendRunning cost: $0/mo to start
Why CanICodeThis says Borderline
Multi-step email sequences with scheduled delays via a transactional email API share this register's CRM build pattern
Open and reply tracking is a well-documented webhook pattern
For outreach to contacts you already have, this is genuinely a weekend build
The parts that'll cause problems
A searchable database of verified contacts at other companies is licensed, continuously-updated third-party data — not something a build acquires
Deliverability at scale is the same ongoing reputation problem every email tool on this register faces
Automatically pausing a sequence when someone replies needs reliable inbound-email parsing
How I'd build this
frontend
Next.js
database
Supabase
email
Resend
hosting
Vercel / Cloudflare Pages
MVP scope
Import a contact list you already have
Multi-step email sequences with scheduled delays
Open and reply tracking
Pause a sequence automatically on reply
Postpone to v2
Contact-discovery database (genuinely licensed data — reconsider before building)
A/B testing subject lines
CRM integration
What it actually costs to build
AI agent — with a subscription (Claude Pro/Max, Cursor, etc.)
$0 marginal
AI agent — pay-per-use API, no subscription
$43–$86 one-time
Hosting, once it's running
$0/mo (free tier)
Domain name, if you want your own
~$12/yr
Existing tools solving a similar problem typically run $13–$49/mo — see how they compare below.
The build prompt
Build me an outreach tool for contacts I already have: import a list, create multi-step email sequences with scheduled delays via a transactional email API, track opens and replies, and auto-pause a sequence when someone replies. Skip contact-discovery entirely — that's licensed data, not a realistic build.