Review your subject line before sending. Check length, emphasis, spacing and personalization variables, then use your audience and purpose to prepare three editable text templates.
Check an email subject line
Free, browser-local writing checks. No account, email sending or open-rate prediction.
Add an audience and a short, accurate purpose to get three editable text templates using your words.
What does an email subject line tester check?
This local tool checks character count, predominantly uppercase text, repeated question or exclamation marks, common personalization markers, spacing and a small list of promotional phrases. Each result explains the rule so you can decide whether it matters for your message.
It does not inspect an inbox, authenticate your sending domain, contact recipients or predict engagement. Inbox placement depends on many factors beyond subject text. The optional templates simply reuse your words; richer AI rewriting is available as a separate task in Okou.
How to check an email subject line
Start with the subject itself; add context when you want text templates.
01
Paste your subject
Enter up to 500 characters. Add an audience and a short, accurate purpose or offer if you want three template variations.
02
Review the checks
Read the explanations and the illustrative inbox preview. Confirm every claim and personalization fallback against the actual email.
03
Edit and copy
Edit the direct, audience-first and purpose-first templates. Copy a draft into your email platform, preview real recipients and test appropriate variants.
What emails can you review?
Use the checks as writing assistance across common business emails.
Newsletters
Make the main topic visible early and keep the subject consistent with the editorial content.
Sales follow-ups
Check emphasis and placeholders while keeping the relationship and next step accurate.
Customer updates
Review launch, event and service updates without unsupported urgency or promises.
How can subject checks improve a newsletter workflow?
Develop the newsletter content and subject together so the inbox promise matches what readers find inside.
The checks above are free and local. This optional AI writing task opens Okou after sign-in and uses credits. Paste the subject and email context there; local input is not sent automatically.Draft subjects in Okou
Zacznij od:
Review the promise before sending
Illustrative example of checks on fictional promotional copy.
Example input
Subject
{{first_name}}, FREE REPORT!!! ACT NOW
Context
A reporting checklist for agency owners, with no stated deadline.
What needs attention
1
Check personalization
Confirm the first-name variable and a safe fallback in the sending platform.
2
Review emphasis and claims
Repeated punctuation and uppercase copy need review. Confirm that the report is free and avoid unsupported urgency.
3
Choose a clearer direction
A human-edited option is Your weekly client reporting checklist. The local tool does not predict whether it will win a campaign test.
Illustrative editorial example, not measured campaign performance or an automatically generated rewrite.
Uzyskaj lepsze wyniki dzięki konektorom
Bring your draft, audience and intended action to Okou for context-aware subject options and an experiment brief.
Przydatne łączniki
Gmail
Google Docs
HubSpot
Give the subject the full email context
Develop the newsletter content and subject together so the inbox promise matches what readers find inside.
Yes. The local checks, editable templates and copy buttons work without an account. The separate AI writing task in Okou requires sign-in and uses credits.
Does it predict open rates or assign a spam score?
No. Subject text alone cannot establish opens or inbox placement. The checks are transparent writing rules, and promotional phrases are context prompts rather than a spam verdict.
Are the three alternatives AI-generated?
No. The direct template normalizes spacing and repeated punctuation. The other two prefix your supplied audience or purpose. Edit them to fit the message, or use the optional Okou task for contextual AI rewriting.
How accurate is the inbox preview?
It shows the first 45 Unicode code points as an illustration. Actual display depends on the email app, font, sender name and screen width. Combined emoji can contain more than one code point.
Does the page upload my subject or send email?
No. Local analysis stays in your browser and does not send messages. If you choose the optional Okou writing task, paste your subject and context there yourself.
Which languages are supported?
Length, spacing and punctuation checks work with many scripts. Promotional-phrase checks and draft labels are English-oriented, and word counts use whitespace. Have a fluent reader review non-English subjects.
