SMTP Senpai
SMTP Senpai is MailSenpai's EU-hosted SMTP relay and REST email API for password resets, order confirmations, notifications and website forms. Connect via SMTP on port 2525 or 587 with STARTTLS, the REST API, or a form endpoint for static sites. DKIM signing uses your verified sender domain, with SPF/DKIM/DMARC checks and automatic suppression of bounced addresses. The permanent free plan includes 5,000 emails per calendar month, up to 200 per day and 30 in the preceding hour, one verified sender domain and 7-day sending logs. No card or expiry. Paid annual plans start at EUR 12.90 per month plus VAT for 10,000 emails per month and 90-day logs. An email report is sent weekly on Monday. Official WordPress and Drupal plugins and open-source SDKs support integration. Written support is available in English and Italian. MailSenpai is the separate newsletter and email marketing platform.
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SpamRate
SpamRate is an email deliverability testing platform for teams that send newsletters, transactional messages, and marketing campaigns. Users send a test message to a set of seed mailboxes at Gmail, Outlook, Yahoo, and Zoho, and SpamRate reports where each copy was placed, separating the inbox from spam and from tabs such as Promotions. Every test also runs technical checks on the sending domain, covering SPF, DKIM, DMARC, MX, PTR, BIMI, MTA-STS, and DANE records, together with domain and IP blacklist lookups and an analysis of message content and authentication headers. The results are combined into a spam rate score alongside the specific issues that lowered it, and every test is stored so changes over time stay visible. Scheduled monitors repeat the tests and send alerts when placement or authentication changes. A WordPress plugin brings the same checks into the WordPress admin, and a set of DNS and domain diagnostic tools is available without an account.
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WillItInbox
WillItInbox is an email deliverability and validation platform for SaaS teams, developers, agencies, marketers, and newsletter operators that depend on outbound email.
Teams can generate a unique test inbox, send a real message from their app or ESP, and receive a practical deliverability report across SPF, DKIM, DMARC, BIMI, DNS, reverse DNS, blocklists, TLS, headers, content, links, reputation, and sender infrastructure.
WillItInbox also validates individual emails and bulk CSV lists using syntax, DNS/MX, disposable, role, typo, provider, catch-all, SMTP, suppression, and confidence signals. It includes domain monitoring, DMARC report analysis, sending source visibility, provider reputation checks, API keys, webhooks, scheduled checks, incident diagnostics, inbox placement checks, team workspaces, and exportable reports.
Paid plans start at $39/month. PAYG credits are available for extra email validation and deliverability testing usage.
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