Catch “gmial.com” while the visitor is still on the page.

Half of the leads that never answer were typed wrong. Lynbro Verify checks the address while the visitor is still on the page, and — when you want it — asks them to confirm it with a one-time code by e-mail or SMS.

E-mail domain checkDanish and international phone numbersCodes by e-mailCodes by SMS through jasms.dkA signed proof your server checksBuilt into Lynbro Forms

Free plugin. The e-mail and phone checks need no account; SMS codes and the live phone lookup go through your own jasms.dk account.

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digits from the system’s secure random generator. Only their HMAC is stored, and a code lasts 10 minutes and 5 attempts.

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The domain has to take mailA domain that does not exist gets a sentence under the field.
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Phone numbers stored one way8 Danish digits, or + and the country code, saved as +4512345678.
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A proof your server checksSigned, valid 30 minutes, bound to the address and the form.

Why Lynbro Verify

A DNS hiccup never turns a customer away

If Google Public DNS cannot be asked, the server’s own resolver is; if that cannot confirm either, the address is accepted and the failure is logged. The form is never blocked by a DNS failure.

Checks on, codes when you want them

The e-mail domain and phone checks are on by default and work at once with Lynbro Forms. Confirmation by code is off by default, and you choose which forms ask for one.

A code step your server trusts

A form that asks for a code gets a code step inside the form, and after the right code a signed proof that your server checks before it accepts the form. Rate limits apply per visitor, per address and for the whole site.

Everything you need β€” included, free

No "Pro" tier, no nag screens. The features other plugins paywall are here from day one.

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E-mail domain

The format first, then the domain’s mail servers through Google Public DNS (DNS-over-HTTPS). A domain with only an A record is accepted, as mail servers do (RFC 5321). Answers are cached: a day for a good domain, an hour for a bad one.

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Phone number

Danish 8-digit numbers, or + and the country code with 8–15 digits, stored as +4512345678. Optional live lookup through jasms.dk.

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Codes by e-mail

Sent through the site’s own mail — Lynbro SMTP or any SMTP plugin. 10 minutes, 5 attempts, a new code after 30 seconds.

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Codes by SMS

Through jasms.dk, which makes, sends and checks the code.

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Connect with jasms.dk

Press the button, sign in at jasms (or create an account, also with LynBro ID) and approve; the site gets a key of its own. Disconnecting revokes it at jasms. Or paste an API key you made yourself.

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The key is kept encrypted

In the options table with a key derived from your site’s salts, or in wp-config.php as LYNBRO_VERIFY_JASMS_KEY.

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Rate limits

Per visitor, per address and for the whole site, for both the live checks and the codes.

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A test screen and a log

Test the connection, send yourself a test code, and read the last 200 checks and sends.

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For developers

PHP functions, REST routes and a JavaScript helper — or no JavaScript of your own: data-lynbro-verify on an input and data-lynbro-verify-otp on the form.

Requirements

6.2+WordPresstested up to 7.1
7.4+PHP
GPLv2+License
2Languages

FAQ

Does it send visitor data anywhere?

Only the domain part of an e-mail address goes to Google Public DNS (you can point the lynbro_verify_doh_url filter at another resolver). Phone numbers go to jasms.dk only when you switch on SMS codes or the live lookup.

What if Google DNS is down?

The server’s own resolver is asked; if that cannot confirm either, the address is accepted. The form is never blocked by a DNS failure.

Where is the jasms key kept?

Encrypted in the options table with a key derived from your site’s salts, or in wp-config.php as LYNBRO_VERIFY_JASMS_KEY.

Does it work with my forms?

Lynbro Forms uses all of it by itself. Other forms can use it through data attributes on the input and the form, or through the JavaScript helper.

Does every form ask for a code?

No. Codes are off by default. Switch on e-mail and/or SMS codes, and choose the forms that should ask for one.