cold-email

Write cold emails that get responses. Ultra-short, signal-based, specific. Under 80 words — everything else is noise.

Phase 0: Sender Setup (Do Once)

Before sending a single cold email, your domain needs to pass authentication. Gmail, Yahoo, and Microsoft all reject non-compliant senders.

Required DNS records:

SPF — v=spf1 include:youresp.com ~all (authorizes your sending server)
DKIM — 2048-bit key, set up through your ESP (Resend, SendGrid, Postmark)
DMARC — minimum v=DMARC1; p=none; rua=mailto:you@yourdomain.com

Domain warmup:

New domain: start at 20–30 emails/day, ramp over 4–6 weeks
Production limit: 50–100 emails per mailbox per day, never more
Scale with multiple warmed mailboxes (3–5) rather than volume per mailbox

Health targets:

Bounce rate: under 2% (above 5%, most ESPs suspend you)
Spam complaint rate: under 0.1% (Gmail hard limit is 0.3%)
If open rates are below 30%, the problem is infrastructure, not copy

Phase 1: Gather

Before writing, you need four things. Ask for anything missing:

Recipient — Name, role, company
Your credentials — Past wins, numbers, notable affiliations
Your ask — What you actually want
Signal — A specific, recent, verifiable event about the recipient

Signal types ranked by reply rate:

Leadership change (new role in past 90 days): 14–25% reply rate
Funding round: 12–20% reply rate
Hiring surge (10+ open roles in their function): 10–18% reply rate
Technology adoption (just switched tools): 8–15% reply rate

If no signal exists, use a specific piece of their work — a post, a talk, a product decision. Generic admiration ("I've been following your work") is not a signal.

Phase 2: The Formula

Every email follows this structure. No exceptions.

Subject: [Signal reference or direct question, under 45 chars]

Hey [FirstName],

[Signal + implication — prove you know their specific situation] (1 sentence)

[Your credibility with concrete details] (1 sentence)

[Single, time-specific ask] (1 sentence)

[Name]

Under 80 words. One CTA. No signature block. No "Best regards." No "I hope this email finds you well."

Phase 3: Email Types

Auto-select based on context. Formula stays the same — emphasis shifts.

Type	Signal to use	Credibility to lead with
Investor outreach	Funding round they led, portfolio company they backed	Traction numbers, revenue, growth rate
Advice / Mentorship	Recent talk, article, or decision they made	Specific situation that mirrors what they solved
Job / Internship	Company news, new product, open role	One concrete result with numbers
Partnership	Their recent launch, expansion, or gap	Your users, revenue, or relevant customer
Paid consulting	Their specific expertise applied to your problem	Offer to pay upfront + tight scope

Phase 4: Subject Lines

What works:

Signal reference: [Company]'s Series B — quick thought
Direct question: How is [Company] handling [specific challenge]?
Mutual connection: [Name] said I should reach out
Under 45 characters for mobile

What's dead:

"Quick question" — one of the two most overused cold email subjects in 2026
"Following up" — same
Fake threading: RE: or FW: on a first email
Anything with "free," "guaranteed," "limited time" (triggers spam filters)

Numbers in subject lines get 113% higher open rates. Use them when you have them: Saw [Company] posted 12 SDR roles

Phase 5: Voice

DO:

Lead with the signal — first sentence proves situational awareness
State credentials with numbers: $2M ARR, backed by a16z, ex-Stripe
Make the ask time-specific: 15 min this Thursday? not grab coffee sometime
Randomize send times — 3–8 minute intervals between emails, not batch sends
Send Tuesday–Thursday mornings (Thursday 9–11 AM has highest open rates)

DON'T:

Generic compliments: "I admire your work" with nothing specific
More than one ask per email
Long paragraphs about your background
Emails over 80 words (2.4x lower reply rate vs. 50–125 words)
Being apologetic for reaching out

Phase 6: Follow-Up Sequence

58% of replies come from the first email. But a sequence improves total response by 50%+.

Email 1 → follow up after 2–3 business days
Email 2 → follow up after 3–4 business days
Email 3 → follow up after 5–7 business days
Email 4+ → follow up after 7–14 business days

Follow-up template:

Subject: Re: [original subject]

Hey [Name],

Bumping this — still think [specific reason this is relevant to them].

[Name]

4–7 emails is the optimal sequence length. Stop if they ask you to.

Verify

[ ] Under 80 words
[ ] Opens with a specific, verifiable signal — not generic admiration
[ ] Credibility includes a number or a name
[ ] Single ask with a specific time
[ ] Subject under 45 characters, no spam trigger words
[ ] No "quick question", "following up", fake RE:
[ ] Casual — you'd send this to a colleague
[ ] SPF + DKIM + DMARC set up on the sending domain
[ ] Sending under 100 emails/day per mailbox

See references/guide.md for real examples that got replies from Evan Spiegel, Mark Cuban, and Elon Musk — plus templates by situation and advanced tactics.