Tools
Small tools for people who put email into apps.
Free, no sign-up. Each one answers a question that's hard to answer by guessing.
Deep email check
Is this address likely real? Format, provider rules, throwaway and role addresses, and the domain's MX, SPF, DMARC and DKIM records, with a score. No email is sent.
Sign-in linksLink scanner test
Email yourself a test link and see every request it gets: which network, GET or HEAD, and whether a mail filter opened it before you did.
Sign-in codesSign-in code guess odds
Code length, tries per code and codes per hour in; the chance that someone guesses one per day, per month and per year out. Runs in your browser.
DevelopmentDev mail fence
One send function in Python, JavaScript, PHP, C# or Go that captures mail in development, redirects it on staging and only delivers in production. Runs in your browser.
Then send the email
email59 is an email router with a small API for sign-in codes, alerts and notices. No domain setup, no subscriptions.