SubjectLine.com vs TestSubject: Which Should You Choose in 2026?
Both prices below were read from each vendor's own pricing page on the date shown.
Pricing side by side
| Plan | SubjectLine.com | TestSubject |
|---|---|---|
| tier 1 | Free — Single subject line scores, basic spam detection, character count checks | Free — Unlimited mobile inbox preview simulations across all popular mobile screen sizes |
| tier 2 | $29/mo — Unlimited subject line checks, AI rewrite suggestions, competitor comparisons | — |
| tier 3 | $89/mo — Multi-user seats, bulk CSV testing, white-label client PDF exports | — |
read from both vendors' pricing pages · 22 Aug 2026 · how we verify
Choose SubjectLine.com if
- Email marketers wanting instant copy scoring before sending
- Copywriters testing spam score risks on newsletter headlines
Choose TestSubject if
- Email designers checking mobile subject line line breaks and truncation
- Marketing teams ensuring sender names fit mobile inbox displays
Where each one disappoints
SubjectLine.com
- Full CRM marketing automation workflows
TestSubject
- Automated algorithmic ad budget bidding
Compiled by Stepan Noianov from both vendors' own sites. Something wrong? Report an inaccuracy.
Other options
All SubjectLine.com alternatives All TestSubject alternatives