Pick by what sits around the sending. If you only need mail from your website or app to arrive, a plain SMTP relay is enough. If developers send receipts and password resets from code, a developer-led delivery service fits. If marketing and transactional mail should share one account, look at a suite. Test with your own domain first.
If all you need is contact form replies and order emails landing in the inbox, stay with a plain relay and skip the marketing suites. If that's you, the first group below is all you need. Everyone else should read on: the nine services here are grouped by what they're built around and described from each vendor's own site.
Relay, developer service or suite
Plain SMTP relays. SendLayer offers an SMTP relay and email API for website and app mail. turboSMTP is an email API and SMTP relay for transactional and marketing email.
Developer-led delivery. Postmark is a delivery service for transactional and marketing email with SMTP and an API. Mailtrap is aimed at developer and product teams sending by API or SMTP. Netcore offers one email API for both kinds of mail with, per the vendor, a deliverability team behind it.
Suites with sending built in. Mailjet puts marketing and transactional email together with developer APIs. Elastic Email bundles email marketing, an email API and team inbox tools. Mailchimp Transactional handles event-based notifications such as order confirmations and shipping updates.
Sending only, or a platform around it?
SMTP2GO is a delivery relay. It moves mail from your server to the inbox and stops there. That's the useful lens for every option on this page: some do the same narrow job, and some wrap sending inside a wider product with campaigns, inboxes or help desk tools attached.
A wider product isn't better by default. It's more to set up, more to secure and more to learn. If nobody on your team writes campaigns, a suite adds screens you'll never open. If marketing already lives in another tool, keeping transactional mail on a separate, focused service can also stop a poorly received campaign from affecting your receipts.
One change to know about: the old SparkPost domain lands on Bird, which describes transactional email, campaigns and replies on one platform. Any older comparison that names SparkPost is describing a product that now sits under another brand.
Run an email delivery service that isn't covered? Put it up for review, and it'll be checked against the same three groups.
All nine services, alphabetically
Listed in no particular order of merit, each line with a different vendor claim from the group notes above.
Bird
Best for: Developers who want SDKs, a CLI and MCP support, per the vendor.
Elastic Email
Best for: One platform for campaigns, transactional mail, team chat and help desk, as the vendor pitches it.
Mailchimp Transactional
Best for: Transactional messaging the vendor says is built to scale with your business.
Mailjet
Best for: Marketing and developer teams sharing one service for marketing and transactional email, which the vendor says is built for devs and loved by marketers.
Mailtrap
Best for: Fast delivery with round-the-clock expert support, as the vendor promises.
Netcore
Best for: Integrating in minutes and delivering in seconds, in the vendor's words.
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Postmark
Best for: Apps where receipts and resets must stay apart from promotional mail, which the vendor says never mix on its SMTP and API service.
SendLayer
Best for: Website and app owners who need an SMTP relay or email API, from a vendor that says it works with a long list of platforms.
turboSMTP
Best for: Senders who'd rather keep data in Europe: the vendor cites EU-based data and infrastructure and round-the-clock human support.
Nine services in one table
| Tool | Built around | Good for |
|---|---|---|
| Bird | Email API platform | Sending, campaigns and replies together |
| Elastic Email | API plus marketing suite | Small firms wanting email plus a team inbox |
| Mailchimp Transactional | Event notifications | Order and shipping updates |
| Mailjet | Email marketing and API | Marketers and developers on one account |
| Mailtrap | Developer email delivery | Product teams sending by API or SMTP |
| Netcore | Email API | One API for both kinds of mail |
| Postmark | Transactional email delivery | Keeping transactional and promotional mail apart |
| SendLayer | SMTP relay for websites | Website and app mail |
| turboSMTP | SMTP relay and API | EU-hosted sending |
Advice before you move transactional mail
Treat the switch as a deliverability job, not a settings change. Mailbox providers judge your sending domain over time, so move one stream at a time: password resets and receipts first, since they're the messages people notice most when they arrive late or not at all. Keep the old service live while the new one settles.
If your site runs on WordPress, my guide to WordPress SMTP plugins covers the plugin side of the setup, and the list of email deliverability tools helps you check inbox placement after the move.
Before you touch your DNS records
- Send a test through your own domain, not the provider's sandbox, and check where it lands in Gmail and Outlook.
- Add the sending records the new service asks for and confirm they pass before you move any traffic.
- List every system that sends mail: website forms, shop, app, invoicing tool. One is always forgotten.
- Check how bounces and complaints are handled, so a dead address isn't retried for ever.
- Keep the old relay switched on for a short overlap in case something was missed.
Tick those off and the move itself is usually the quiet part.
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Frequently asked questions
What's the difference between an SMTP relay and an email API?
An SMTP relay accepts mail the same way an email server does, so most websites and apps can use it with a few settings. An API sends mail through code, which gives developers more control and better error details.
Can I send marketing emails through a transactional service?
Some services allow both, and some keep them on separate streams. Keeping them apart protects your receipts and resets if a campaign gets complaints.
Will switching providers hurt my deliverability?
It can dip briefly while mailbox providers get used to the new sending setup. Moving gradually and setting up your domain records first keeps the dip small.
Do I need a developer to change email providers?
Not for a plain SMTP relay on a website: it's usually a matter of new server details and DNS records. Apps that send through an API will need a developer.
Why do my website emails go to spam?
The usual causes are missing domain authentication records, sending from a domain that doesn't match your site, or a shared server with a poor sending history.
Should transactional and marketing mail share a domain?
Many senders use separate subdomains so each stream builds its own reputation. Ask your new provider how it recommends splitting them.
