Email testing and programming guides

Learn how MailSlurp works and how you can use it to achieve email related tasks in code, tests, or online.

For developer references see the API documentation or the example code projects.


Send and receive emails

Use inbound and outbound email in code, mail-clients, or online dashboard. Add attachments, configure webhooks and gain SMTP access.

Receive inbound SMS TXT messages with API and webhooks

How to create phone numbers and read text messages in code and tests


Introduction to MailSlurp

Install and configure MailSlurp using SDK libraries or REST API.

Creating inboxes

How to create an inbox with MailSlurp to send and receive emails with.

Wait for matching email content

How to wait for emails in code that match search criteria. Pattern matching and regular expressions.

Testing User Sign-Up and Email Confirmation

A tutorial on testing email dependant actions using MailSlurp test email accounts. Intercept inbound emails in tests and extract confirmation codes to test user sign-up and email verification.

Testing SMS based authentication (2FA/OTP)

How to test applications that use two-factor authentication and one-time TXT message passwords.

Testing OTP password link username and password for 2 factor authentication (2FA)

Testing OTP password link username and password for 2 factor authentication (2FA)

Team email accounts

How to manage MailSlurp team access to an organization.

Sending emails in code and tests

How to send emails and attachments in code and tests.

SMTP IMAP Settings

How to access MailSlurp email accounts using IMAP and SMTP servers

Receive emails and attachments with Webhook Push

Receive emails with http webhooks. Webhooks let you respond to inbound email streams in real time on your server or within an application.

Inbox rules: permissions and routing (allow, block, filter)

How to set inbox routing rules to block or allow inbound or outbound emails using patterns.

How to configure Mail desktop clients with MailSlurp

How to setup MailSlurp with Outlook, Gmail, Thunderbird, Mail app and more.

Email verification: checking a list of email addresses to reduce bounces

Avoid bounces and deliver emails to your customers with email verification and validation.

Email tracking pixels

See if emails are opened by sending tracking pixels. Receive open events via Webhook or view which recipients opened an email in the MailSlurp dashboard

Email auto-forwarding rules

Create email forwarding rules for inbound emails to reroute messages.

Email address custom domain setup - (step by step guide)

How to create email address with wild-card catch all using MailSlurp. Screenshots included.

CSharp send SMTP email

How to use CSharp SMTP client to send email with MailSlurp mail server


Send and receive email attachments. How to attach files to SMTP emails.

Email Aliases

Email forwarding API for automatic email proxy. Setup auto-forwarding email aliases to mask a real email address.

Receiving and reading emails

Read emails and attachments in code and tests. Wait for unread emails using long-polling or webhooks.

Extract email content

Use regex or server side matching to extract email content

Account setup and usage

Sign-up and login. How to manage your email settings, account plan, and team access.


Developer example projects and guides are available in many languages and frameworks.

How do SMTP servers work and what is a fake smtp server

What are SMTP ports

What are DKIM records

MailServers use TCP ports to transmit emails. Picking the right port between 25 vs 2555, 465 vs 587 in SMTP is easy with this guide.

Fetch emails and attachments in code waiting for new emails to arrive using MailSlurp

Transactional Email API Fundamentals

How to manage email subdomain custom mailboxes using SMTP/IMAP mailserver settings.

Use MailSlurp's Playground to test ideas or integrations with a real user sign-up, verification, and login process.

Test email accounts for CypressJS. End-to-end testing with real email addresses using MailSlurp Cypress plugin.

How to test HTTP webhooks using MailSlurp test hooks.

Free test email address for testing emails online with web dashboard or REST API.

Manage team access to email inboxes within an organization.

Every email service provider, such as Google's Gmail, has a unique spam filter, which means that your test emails must be thorough.

How to send email with telnet mail commands

How to send emails using the Dashboard, API, or SDK clients.

How to send emails at a specific time or delay sending with email scheduling tools.

The difference between HTTP and SMTP inboxes and domains in MailSlurp.

How to use SMTP relay to address spam and security issues that affect outbound mail servers.

How to refresh your account API Key

Setup bounce notification webhooks for your account to reduce email bounces

Receive emails in code and tests

Manage payment, access, and usage limits. How to upgrade, alter your subscription, and view invoices.

How to send and receive emails in PHP

NBSP HTML Entities

Setup team enterprise access using identity providers such as AD, Okta, OneLogin and more.

Mailto link use in HTML

How to manage sending limits and spam detection

How to test SMTP, POP3, and IMAP inboxes using MailSlurp.

Use SMTP nodemailer with MailSlurp disposable email addresses

Free IP Address API. Query IP address for domains and urls.

The ultimate guide to testing OAuth one-time-password flows with real SMS MFA. Use Playwright to automate authentication tests with programmable TXT message APIs.

How MailSlurp secures your emails and what security features are available.

Send email in Visual basic

A guide to reduce rate-limit exceptions when using HTTP APIs

How to read emails and attachments in application, tests, or the MailSlurp dashboard.

How to create email templates for transactional emails

587 vs 465 vs 25 vs 2525 - which port is the right one for SMTP mailservers?

There are many free tools to test emails before sending. This can help prevent spam warnings and increase deliverability.

Fetch and read emails with GraphQL inboxes using MailSlurp email API.

How to test emails before sending using email testing APIs like MailSlurp

How to test emails before sending using email testing APIs like MailSlurp

Create phone numbers that handle inbound SMS messages and direct them to your application or test suites

Fetching emails in code

Create auto expiring inboxes using MailSlurp disposable mailboxes

MailSlurp custom email address guide for catch all email routing.

Email size limits

How to control the seen or read settings for an email using MailSlurp.

Use dummy test email accounts to test email end-to-end.

Check email addresses are real and exist using MailSlurp email verification.

Difference between IMAP POP3 and SMTP

Send and receive emails in Deno JS. Use APIs in Deno with MailSlurp.

Email dashboards for testing and development

Use MailSlurp to fetch name server records. These are useful for verifying domains and querying mail servers.

DMARC – All Facts that you should know

How to use custom domains with MailSlurp to create your own email addresses.

Configure identity providers like Okta to enable enterprise SSO login

SMTP mailserver testing and usage in CSharp using

How to encode files as Base 64 encoded strings in several languages

What is cc and bcc in email? What is the difference between cc and bcc?

What is BCC email field (blind carbon copy) and how does it differ to CC?

How to send emails that don't trigger a spam warning.

Use your api access token to call the MailSlurp API and control your inboxes remotely.

A guide to PHP Mailer

Wait for email API

Use MailSlurp's attachment endpoints to upload, send, receive, and download attachments.

Analyse emails for vulnerabilities and viruses. Get DMARC, SPF, and DKIM verdicts for emails with MailSlurp.

Submit forms directly to email. No code or sign-up required.

Send and receive test email accounts (3 easy steps)

Build powerful applications and test suites using real email addresses in code. Create inboxes on demand then send and receive emails and attachments in Javascript, Go, PHP, Ruby, Java, C#, REST and more.