Resources

Email guides, examples, and resources

Everything the Loops team has learned about sending email people actually open. Start with a guide, browse the examples, or look up a term.

Guides

How to make sure your email lands and gets read.

Email deliverability best practices

Email deliverability best practices

What decides whether your email reaches the inbox, and how to improve it.

What decides whether your email reaches the inbox, and how to improve it.

Why emails go to spam

Why emails go to spam

The common triggers that send mail to spam, and how to fix them.

The common triggers that send mail to spam, and how to fix them.

The best time to send email

The best time to send email

When to hit send for the most opens, based on the data.

When to hit send for the most opens, based on the data.

The 10 best email marketing automation platforms for SaaS

The 10 best email marketing automation platforms for SaaS

Event-driven lifecycle tools compared on SaaS fit and price.

Event-driven lifecycle tools compared on SaaS fit and price.

The 10 best email APIs for developers

The 10 best email APIs for developers

Resend, SendGrid, Postmark, SES, and more, with the tradeoffs for each.

Resend, SendGrid, Postmark, SES, and more, with the tradeoffs for each.

The 8 best transactional email services

The 8 best transactional email services

Postmark, SES, Mailgun, and more, compared as full services rather than APIs.

Postmark, SES, Mailgun, and more, compared as full services rather than APIs.

Transactional email best practices for SaaS

Transactional email best practices for SaaS

Reliability, security, consent, retries, monitoring, and testing for account-critical email.

Reliability, security, consent, retries, monitoring, and testing for account-critical email.

Send email from AI agents

Send email from AI agents

Point a coding agent at Loops and let it wire up sending.

Point a coding agent at Loops and let it wire up sending.

SMTP ports, IMAP vs POP3, and email verification

SMTP ports, IMAP vs POP3, and email verification

Which protocols and ports to use for sending, mailbox access, and verification.

Which protocols and ports to use for sending, mailbox access, and verification.

SaaS email program audit

SaaS email program audit

Score consent, data, lifecycle coverage, safety, deliverability, and measurement.

Score consent, data, lifecycle coverage, safety, deliverability, and measurement.

Send transactional email from Node.js

Send transactional email from Node.js

Working SDK code for Node backends, with retries, idempotency, and testing.

Working SDK code for Node backends, with retries, idempotency, and testing.

The 12 best email deliverability tools

The 12 best email deliverability tools

Inbox testers, DMARC monitors, and list cleaners, compared.

Inbox testers, DMARC monitors, and list cleaners, compared.

Email A/B testing

Email A/B testing

What to test, how to size a test, and how to read the results.

What to test, how to size a test, and how to read the results.

Email churn rate

Email churn rate

How to measure list churn and slow the losses you can control.

How to measure list churn and slow the losses you can control.

Email marketing laws

Email marketing laws

CAN-SPAM, GDPR, and CASL, explained in plain English.

CAN-SPAM, GDPR, and CASL, explained in plain English.

Lifecycle email

Lifecycle email

The automated messages every SaaS should run, and how to trigger them.

The automated messages every SaaS should run, and how to trigger them.

Email marketing KPIs

Email marketing KPIs

The metrics that matter, how to calculate them, and which ones to prioritize.

The metrics that matter, how to calculate them, and which ones to prioritize.

Send transactional email from Next.js

Send transactional email from Next.js

Working SDK code for signup sync, password resets, environment setup, and testing.

Working SDK code for signup sync, password resets, environment setup, and testing.

Migrate from SendGrid to Loops

Migrate from SendGrid to Loops

A practical package swap, API mapping, template setup, and deliverability checklist.

A practical package swap, API mapping, template setup, and deliverability checklist.

Migrate from Mailchimp to Loops

Migrate from Mailchimp to Loops

Move marketing contacts, campaigns, and Mandrill transactional email across, without hurting deliverability.

Move marketing contacts, campaigns, and Mandrill transactional email across, without hurting deliverability.

Migrate from Customer.io to Loops

Migrate from Customer.io to Loops

Map people, attributes, events, and workflows to Loops, with before and after code and a cutover checklist.

Map people, attributes, events, and workflows to Loops, with before and after code and a cutover checklist.

Migrate from Postmark to Loops

Migrate from Postmark to Loops

Swap the SDK, map template sends to dataVariables, verify your domain, and cut over one email type at a time.

Swap the SDK, map template sends to dataVariables, verify your domain, and cut over one email type at a time.

Migrate from Mailgun to Loops

Swap the SDK, map template sends to dataVariables, verify your domain, and cut over one email type at a time.

Migrate from Brevo to Loops

Swap the SDK, map each call, verify your domain, and cut over one email type at a time.

SMTP error codes explained

What SMTP reply codes like 421, 550, and 554 mean, and how to fix them.

Customer engagement tools

What counts across email, in-app, push, chat, and analytics, with 9 options compared.

Free tools

Free email tools you can use right now, no signup required.

Email by type

Loops sends every kind of email from one platform. Pick the job you need to do.

Email examples

Emails you can copy, with notes on why they work.

Email glossary

Plain-English definitions for the terms you will run into.

Common questions

What is the difference between transactional and marketing email?

What is lifecycle email?

Do I need a separate tool for transactional and marketing email?

Does Loops have a free plan?