Choose a SendLayer alternative by how your team sends mail. If developers own sending, pick an API-first service with clear logs. If a website just needs reliable SMTP, a relay with simple setup is enough, and if marketing and app emails should share one account, pick a platform that handles both.
If your app or website sends receipts, password resets and sign-up confirmations, those emails have one job: arrive, quickly, in the inbox. SendLayer offers an SMTP relay and an email API for website and app mail. The eight services below, in no particular order, do the same core job, and the differences sit in setup, monitoring and how much they offer developers.
Three tests for any sending service
The useful questions for any replacement are how sending is set up, how deliverability is monitored, and what the API gives developers.
Setup
Check how you'd connect your site or app: an SMTP relay you paste into a plugin, an API your code calls, or both. Then check domain verification. You'll need to add records such as SPF, DKIM and DMARC to your domain, and a good service walks you through each one and tells you when they're working.
Monitoring
Sending isn't the same as arriving. Look for logs of every message, bounce and complaint handling, and alerts when something goes wrong. If a password reset doesn't arrive, someone on your team should be able to find out why in a minute, not an afternoon.
The developer side
Developers will look at the API, webhooks for events such as bounces and opens, libraries for their language, templates and whether there's a test mode. If your sending lives in code, ask a developer to try a few calls before you commit. It's also worth checking how each service handles inbound mail, if your app needs to receive replies, and how long logs are kept, since you'll want history when a customer says an email never arrived.
SendLayer alternatives side by side
| Tool | Service type | Good for |
|---|---|---|
| Elastic Email | Sending platform with API | Marketing, API sending and team mail in one |
| Mailchimp Transactional | Event-based email and SMS | Order, shipping and payment notifications |
| MailerSend | Email API and SMTP | Teams sharing one sending account |
| Mailgun | Developer email API | Sending, receiving and tracking email in code |
| Mailjet | Marketing and transactional email | Marketers and developers working on the same emails |
| Postmark | Transactional delivery service | Fast delivery of app emails |
| Resend | Email for developers | Developer teams sending at scale |
| SMTP2GO | SMTP relay and API | Sites needing reliable SMTP with reporting |
Eight sending services, A to Z
Alphabetical and in no particular order. Each line reflects what the vendor says about its own service.
Elastic Email
Best for: Growing businesses wanting email marketing, an email API and team communication tools in one account, as the vendor describes it.
Mailchimp Transactional
Best for: Stores sending event-based messages such as order confirmations, shipping updates and payment notices by email or SMS, which the vendor builds this service around.
MailerSend
Best for: Product teams wanting a team-friendly email API and SMTP for modern apps; the vendor names a free plan for getting started.
Mailgun
Best for: Developers who need to send, receive and track email through APIs, with a free plan named on the vendor's site.
Mailjet
Best for: Businesses where marketers and developers share email work, with the vendor offering design, delivery and automation plus developer APIs and GDPR compliance.
Postmark
Best for: Developers who care most about app emails arriving on time, which the vendor puts at the centre of its delivery service.
Resend
Best for: Engineers who want a developer-focused service for transactional and marketing email at scale, with the vendor's pitch built on staying out of spam folders.
SMTP2GO
Best for: Websites and apps needing an SMTP relay with servers around the world, an API and reporting, according to the vendor, which also names a free plan.
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API-first or all-in-one?
Built for developers and app mail
Postmark, Resend, Mailgun and MailerSend put developers and transactional mail first. SMTP2GO pairs a plain SMTP relay with an API and reporting, so it suits website owners who just need a plugin to send reliably as much as engineering teams.
Marketing and app mail together
Mailjet and Elastic Email combine marketing campaigns with transactional sending, which helps when one small team handles both. Mailchimp Transactional is aimed at event-based messages such as order and delivery updates, by email or SMS. Keeping marketing and app mail on separate sending domains or streams is wise either way, so a campaign problem can't hold up a password reset.
Which camp fits your team
If a developer will own the integration and nobody in marketing will touch it, the first camp keeps things lean and focused on delivery. If one person runs the newsletter and the shop emails, the second camp saves them from learning two systems. And if your site is a small WordPress build that only sends contact form notifications and order emails, a straightforward relay with a plugin is often all you'll need.
Advice for switching transactional email
Move one stream at a time. Verify your domain on the new service, send your quietest type of message first, such as internal alerts, and watch the logs for a few days before you move password resets and receipts. Keep the old service live until the new one has a clean record, then switch it off.
If your site runs on WordPress, my guide to WordPress SMTP plugins covers the connecting piece, and my list of email deliverability tools helps you keep an eye on inbox placement after the move. Whichever service you pick, don't skip the domain records: they're what tells inbox providers your mail is really from you. Email and privacy rules vary by country, so check with your regulator before sending anything marketing-related.
Do you make transactional email services? Tool makers can ask to be considered for a featured place on this list.
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Frequently asked questions
What's the difference between transactional and marketing email?
Transactional emails are triggered by something a person did, such as a purchase or a password reset. Marketing emails are campaigns sent to many people at once.
Should I use SMTP or an API to send email?
SMTP is the easy option for websites and plugins. An API gives developers more control, richer error details and events through webhooks. Many services offer both.
Do I need SPF, DKIM and DMARC records?
Yes. These domain records prove your mail is really from you, and major inbox providers expect them. Your sending service should show you which records to add.
Why do my website emails go to spam?
Common reasons are missing domain records, sending from a generic server, or mixing marketing and transactional mail. A dedicated sending service with verified records fixes most of these.
Can I keep marketing and transactional email in one service?
You can, and some services are built for it. Use separate streams or subdomains so problems with campaigns don't delay receipts and password resets.
How long does it take to move to a new email service?
A small site can move in an afternoon once domain records are verified. Apps with many message types should move one stream at a time over a week or two.
