SPF Checker: How to Validate SPF Records and Fix Common Failures
6 min readLearn how to use an SPF checker to validate SPF records, inspect include chains, fix multiple-record problems, and troubleshoot sender authorization failures.
Read guideEmail testing, deliverability, and API guides
Build more reliable email and SMS workflows with practical MailSlurp tutorials, implementation guides, and production-ready testing advice.
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DeliverabilitySMTP Server Configuration Checklist: Host, Port, TLS, Auth, and DNS
5 min readConfigure SMTP correctly with a practical checklist for host, port, TLS, authentication, sender identity, and testing from staging to production.
Read guideSMS Verification API for OTP and MFA Testing
4 min readLearn how an SMS verification API supports OTP and MFA testing, what workflows teams should validate, and how to avoid flaky auth automation.
Read guideSendGrid Alternative: How To Compare Options by Workflow, Testing, and Inbound Email
7 min readEvaluate a SendGrid alternative by outbound delivery, inbox testing, inbound handling, sender diagnostics, and workflow ownership so you choose a platform that matches how your team actually ships email.
Read guideSelenium Email Testing for Transactional Flows and MFA
4 min readLearn how to use Selenium email testing to verify signup, password reset, OTP, and MFA flows with real inboxes and deterministic message assertions.
Read guidePlaywright Email Testing and Email Verification for OTP, Magic Links, and Password Resets
7 min readLearn how to do Playwright email testing and Playwright email verification with real inboxes and phone numbers so you can verify OTP codes, magic links, password resets, and transactional messages in CI.
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DeliverabilityPHP Email Validation Guide: Syntax, Domain Checks, and Real Verification
5 min readLearn how to validate email addresses in PHP with filter_var, when to use DNS checks, why regex alone is weak, and how to verify real email flows before release.
Read guidePhone Verification API for Test Automation Teams
4 min readLearn how a phone verification API supports signup, login, recovery, and MFA test automation with programmable numbers, deterministic waits, and real message assertions.
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SMS & OTPOTP testing and OTP checker workflows for email, SMS, magic links, and MFA
14 min readUse OTP testing and OTP checker workflows to validate email codes, SMS verification, magic links, MFA, expiry, resends, and one-time use.
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Email designNBSP Character Explained: How To Use Non-Breaking Spaces in HTML and Email
6 min readLearn what the NBSP character means, how ` ` works in HTML, when to use non-breaking spaces, how it differs from normal spaces, and how to debug formatting problems in web pages and email templates.
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DeliverabilityMX Record Lookup Guide: How to Verify Email Routing and Troubleshoot Delivery
5 min readLearn what MX records do, how to check them with dig and nslookup, how MX interacts with SPF, DKIM, and DMARC, and how to verify email routing safely.
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Email designMailto Link Guide: Syntax, HTML Examples, Parameters, and Better Alternatives
7 min readLearn how a mailto link works, how to build mailto syntax in HTML and JavaScript, how to encode subject and body fields correctly, and when to use an email API instead.
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