Free email spam and unsubscribe test
Is your email ready for Gmail and Yahoo?
Email Test is a free tool by Przemysław Zalewski, an independent engineer.
Test a campaign or cold email step before it goes out. Send one email to your test address and get a report on one-click unsubscribe, SPF, DKIM, DMARC and spam signals, a verdict from 3 AI models, and fixes your AI agent can apply.
Free · no sign-up · deleted after 24 hours
Who uses the email test
- Cold email and sales teams. Test a sequence step from Instantly, Smartlead, Lemlist or your CRM before it goes to thousands of prospects.
- Marketing and lead generation agencies. Check a client's newsletter in two minutes and send them the report link instead of a screenshot.
- Newsletters and shops. Find out why the campaign lands in spam or Promotions, and fix the unsubscribe flow Gmail and Yahoo now require.
- SaaS sending from its own app. Verify DKIM, alignment and one-click unsubscribe on emails your code sends, after every change to the template or the provider.
How it works
- Get an address. Click the button. You get a unique address like test+k7f2q9mx@ciunkos.com, valid for 24 hours.
- Send your real email. Send the email you want to check from the tool you normally use: your newsletter platform, CRM, cold email tool or app.
- Read and fix. Each problem comes with an explanation and a fix. Copy one instruction, or all of them, for your AI agent, or ask me to do it.
What the email spam test checks: unsubscribe, SPF, DKIM, DMARC
One-click unsubscribe and List-Unsubscribe
List-Unsubscribe and one-click unsubscribe (RFC 8058), whether your DKIM signature covers those headers, the visible link in the body, and whether the unsubscribe page opens without login. On request we send the real one-click POST.
SPF, DKIM and DMARC
SPF, DKIM (we verify every signature ourselves and say why one fails), DMARC with alignment, reverse DNS of the sending server and TLS, shown step by step the way a receiving server sees them. Learn the terms in the glossary: SPF, DKIM, DMARC, BIMI.
Your domain
The DNS grade of your sending domain and BIMI, from our SPF, DKIM and DMARC checker and BIMI checker.
Spam signals in the content
Spam signals with points per rule: images versus text, link shorteners, links whose text shows another address, Gmail clipping above 102 KB, missing plain text, shouty subjects, risky attachments.
AI panel: how filters and readers see it
Three models (Claude Haiku, Cloudflare Clef and Llama 4 Scout) read the text, the links and a screenshot of the rendered email and vote: normal, marketing, suspicious, spam or phishing. You also get the likely Gmail tab and copy suggestions, each ready to paste into your AI agent.
Safe email preview
A safe render of your email on desktop and mobile width, a screenshot, the plain-text version and all headers. Images load through our proxy. Download the .eml for 24 hours.
Gmail and Yahoo sender rules in plain words
Since February 2024 Gmail and Yahoo ask every sender for SPF or DKIM, reverse DNS, TLS and a low spam rate. Bulk senders (Google counts about 5,000 messages a day to Gmail addresses) also need SPF and DKIM, a DMARC record, DMARC alignment and one-click unsubscribe with a visible link, and must honor unsubscribes within 2 days. The report marks each rule we can check from your email and says where to see the rest. Source: Google email sender guidelines. Need help meeting the bulk sender rules?
A suspicious email in your inbox? Check if it is phishing →
Email test questions
Is it free? Are there limits?
Free, no account. Each test address works for 24 hours and accepts up to 5 emails, so you can fix and resend. You can create a new address whenever you want.
What happens to my email?
The email and its report are stored for 24 hours from the moment you create the address, then deleted automatically. Only people with the report link can see it. We do not send anything to anyone, and the email is not used for anything else.
Will this tell me whether I land in the inbox or in Promotions?
No, and no single test can. Placement depends on your domain reputation and on how readers react over time. This test checks everything you control in the email itself. Promotions is Gmail sorting marketing email; it is normal for newsletters and is not the spam folder.
Will the test unsubscribe my test address?
We open the unsubscribe page with a normal visit (GET). RFC 8058 says a visit must not unsubscribe, but badly built pages sometimes do. The one-click POST runs only when you click the button.
Why do my emails go to spam or Promotions?
Spam is usually a mix of: no DKIM signature with your own domain, no DMARC, no one-click unsubscribe (so readers press "spam" instead), a sending domain or IP with a poor reputation, and content signals such as image-only email or link shorteners. Promotions is different: Gmail sorts marketing email there on purpose, and a newsletter belongs there. This test shows the setup and content signals; reputation lives in Google Postmaster Tools.
How do I add one-click unsubscribe?
Most newsletter platforms add it once you authenticate your own domain. In your own code, add two headers to bulk email: List-Unsubscribe with an https URL (a mailto is optional) and List-Unsubscribe-Post: List-Unsubscribe=One-Click, sign both with DKIM, and make the URL accept a POST that unsubscribes without login. Then send a test here and press "Test one-click for real".
How do I test the List-Unsubscribe header?
Send one email here. The report shows List-Unsubscribe and List-Unsubscribe-Post, whether a DKIM signature of your domain covers them, whether the unsubscribe page opens without login, and lets you send the real one-click POST that Gmail sends.
Should I forward my email or send it directly?
Send directly from your platform (a test send). A normal forward replaces the sender and the headers with your own mailbox. Forwarding as an attachment works for content and DKIM, but not for SPF.
Looking for a mail-tester alternative? How is this different from mail-tester, MailGenius, GlockApps or Mailtrap?
mail-tester shows a SpamAssassin score and gives 3 free tests a day (their FAQ, October 2026). GlockApps sends to real seed inboxes and measures placement, on paid plans (their pricing page, October 2026). MailGenius and Mailtrap also score content. This test focuses on the 2024 Gmail and Yahoo rules: it checks whether one-click unsubscribe really works and is signed, verifies DKIM itself and explains why it fails, adds a panel of three AI models that read your email like a filter and a reader, and writes each fix as an instruction for an AI agent.
What is "Copy instruction for agent"?
A ready prompt with the context from your email (platform, domains, records) and the exact steps. Paste it into Claude, ChatGPT, Cursor or another AI agent that can see your DNS or code, and it can guide you or make the change.
I do not understand the report. Can you fix it?
Yes. I set up email for SaaS products and agencies: one-click unsubscribe, suppression lists, bounce handling, DKIM and DMARC. See email work I do or the price and start date.
Need help with your email setup?
I build and fix email infrastructure: one-click unsubscribe, suppression and bounce handling, authentication, sending from your own app.
