Writing that delivers.
Deliverability guides and product notes — no filler.
How to verify emails with n8n
Verify emails with n8n using the HTTP Request node: POST each new signup to the Qualisend API, then branch on the status with an IF or Switch node.
Verify emails from Airtable without a plugin
Two ways to verify emails from Airtable with Qualisend: a real-time automation script that writes the status back, or a bulk CSV export.
How to clean your MailerLite list: inactive isn't invalid
MailerLite's Clean up inactive tool judges engagement, not validity — so it isn't verification and misses never-mailed invalids. Here's how to catch them.
How to verify emails from Jotform
Two practical ways to verify emails from Jotform with Qualisend: a real-time webhook that calls the API on submit, and a bulk CSV/Excel export.
Verify emails from HubSpot forms in real time
Verify emails from HubSpot forms two ways: a real-time Operations Hub workflow that calls the Qualisend API, or a bulk CSV export. No native app.
Verify emails from Gravity Forms
Verify emails from Gravity Forms with a PHP validation filter, the Webhooks Add-On, or a bulk CSV export — reject or tag bad addresses at submit.
SPF, DKIM, and DMARC explained
SPF, DKIM, and DMARC are the DNS records that prove your mail is really yours — and mandatory for bulk senders since 2024. What each does, explained.
How to validate an email address in Rails
Validate an email address in Rails in three layers: a URI::MailTo format rule, a Resolv MX validator, and an SMTP mailbox check via API.
How to validate an email address in Express
Validate an email address in Express: express-validator for syntax, a dns/promises MX lookup, and a verification API for the mailbox.
How to validate an email address in Flask
Validate an email address in Flask properly: WTForms' Email() for syntax, an MX lookup via check_deliverability, then an API for the mailbox check.
How to validate an email address in Spring Boot
Validate an email address in Spring Boot: @Email for format, a JNDI MX lookup, and an API-backed ConstraintValidator — with working code.
Validate an email address in ASP.NET Core
Validate an email address in ASP.NET Core in three layers: DataAnnotations for syntax, DnsClient.NET for MX, and an async FluentValidation API check.