✦ Free Tool

Grade your subject line
in 5 seconds

Spam check, curiosity score, mobile preview, and predicted open rate — against real Klaviyo DTC benchmarks. Get 10 AI alternates + a weakness breakdown.

0 characters
Your vertical:
Analyzing…
–
–
Score: –
Characters
–
Words
–
Emoji
–
Score breakdown
Hook Strength
–
Curiosity Gap
–
Specificity
–
Length & Mobile Risk
–
Mobile preview
Your Store <hello@store.com>
–
–
Predicted open rate
vs. Klaviyo DTC benchmark
–
–
Signals detected
Why this grade
  • Generating explanation…
Free — instant delivery

Unlock 50 proven subject line templates + 10 AI variants for yours

Enter your email and we'll send you the 50 highest-performing DTC subject lines by vertical (ready to adapt) plus 10 AI-written rewrites of your specific subject line with a 4-point weakness breakdown.

50 vertical templates 10 AI variants Weakness breakdown Sent instantly
No spam. Unsubscribe anytime. We'll also send you 3 email strategy tips over 8 days.
10 AI-rewritten variants

First 3 are angled (curiosity / urgency / value). All scored with the same engine. A/B test the top 2 — winner usually surfaces in 200 sends.

Weakness breakdown

We also sent these to your inbox for reference.

Subject lines are the tip of the iceberg

Want a full 6-point audit of your entire email program?

This was just your subject line. A full audit surfaces missing flows, revenue gaps, and writes 3 custom Welcome Series emails in your brand voice.

  • Email tool detection (Klaviyo, Privy, Omnisend)
  • Revenue gap estimate in real dollars
  • 6-point scored audit — grade per category
  • 3 custom Welcome Series emails written for your brand
Run my free store audit →

Why it matters

Your subject line is worth $4,200 a month

A 10-point score improvement typically means a 6–9% open rate lift. On a 10,000-subscriber list, that's the math:

+700
More opens per campaign
On a 10k list, grade C→B lift
+2%
Avg. CTR on those extra opens
14 more clicks per campaign
$4.2k
Recovered monthly at $50 AOV
Across 3 campaigns/week
💡
The subject line is the single highest-leverage variable in email. It determines whether all your copy, design, and timing even get a chance to convert. Klaviyo's 2026 DTC benchmark: top-quartile brands average 32–38% open rates vs. 18–22% for average senders. The gap is almost entirely subject lines, send times, and segmentation — not design.

How it works

What we actually grade

No vibes. Deterministic scoring + AI analysis on top.

📏
Length analysis
Characters, words, and mobile preview cutoff — iPhone Gmail clips at ~41 chars.
🚨
Spam trigger check
25+ flag words and patterns that trip inbox filters before a human ever sees it.
🧲
Curiosity score
Open-loop signals, specificity, personalization markers, and urgency cues.
😐
Emoji sentiment
1–2 emojis can lift opens. 3+ reads as promotional noise to most readers.
📊
Predicted open rate
Predicted range vs. Klaviyo DTC benchmarks for your specific flow type.
🤖
AI alternates + breakdown
10 rewritten variants with predicted scores + a 4-point weakness breakdown with fixes.

Ready to grade your whole email program?

Subject lines are one signal. Missing flows, bad timing, and weak segmentation are the real revenue leaks. A full audit surfaces all of them — free, no Klaviyo login.

Run free audit → $299 build →
Also try →
Send Time Optimizer
Find the optimal send windows for your vertical — 3 ranked time slots with predicted open rates.
→