Template checker
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Mailbox calculator
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SPF generator
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DMARC generator
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DKIM generator
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Deliverability test
Email deliverability test
1. Send your test message to these addresses
Each address carries a unique tracking token so we know which test the inbound observation belongs to. Copy the full list, paste into the BCC field of your campaign, and send.
seed-310ce181d5115e57@yahoo.com
seed-310ce181d5115e57@gmx.com
seed-310ce181d5115e57@hotmail.com
seed-310ce181d5115e57@gmail.com
seed-310ce181d5115e57@warmup-m365.com
seed-310ce181d5115e57@outlook.com
seed-310ce181d5115e57@icloud.com
seed-310ce181d5115e57@hey.com
seed-310ce181d5115e57@proton.me
seed-310ce181d5115e57@warmup-seed.com
seed-310ce181d5115e57@aol.com
seed-310ce181d5115e57@zoho.com
seed-310ce181d5115e57@yandex.com
seed-310ce181d5115e57@mail.ru
seed-310ce181d5115e57@fastmail.com
Tracking token for this session: 310ce181d5115e57
2. Per-provider coverage
| Provider | Bucket | Address template |
|---|---|---|
| Yahoo | Yahoo | seed-{token}@yahoo.com |
| GMX | Other | seed-{token}@gmx.com |
| Hotmail | Microsoft | seed-{token}@hotmail.com |
| Gmail | seed-{token}@gmail.com | |
| M365 | Microsoft | seed-{token}@warmup-m365.com |
| Outlook | Microsoft | seed-{token}@outlook.com |
| Apple | Apple | seed-{token}@icloud.com |
| Hey | Other | seed-{token}@hey.com |
| ProtonMail | Other | seed-{token}@proton.me |
| Workspace | seed-{token}@warmup-seed.com | |
| AOL | Yahoo | seed-{token}@aol.com |
| Zoho | Other | seed-{token}@zoho.com |
| Yandex | Other | seed-{token}@yandex.com |
| Mail.ru | Other | seed-{token}@mail.ru |
| Fastmail | Other | seed-{token}@fastmail.com |
What we measure
- Inbox % — fraction of seeds that received the message in the primary inbox.
- Spam % — fraction routed to Spam / Junk.
- Promotions / Updates — Gmail tab classification.
- Not received — message never seen within the verification window.
Inbox % is computed against received seeds only — partial-coverage tests still get a meaningful inbox % rather than being deflated by undeliverable seeds.
Why this matters
ESPs differ. A campaign that lands cleanly in Gmail can be greylisted by Microsoft or routed to Yahoo Spam — exactly the divergence the SPF, DKIM and DMARC generators are designed to fix.