At Inveigle.net, we have evaluated numerous SMTP relay service providers for use with our or other SMTP-compliant products. This isn’t a "n best SMTP providers of 2024" list that blindly links to every SMTP provider with an affiliate programme - some of the providers on those lists are terrible. We ONLY include providers that have simple pricing, not those that add additional bandwidth charges or charge more for larger e-mails or based on subscriber numbers. We also don’t include providers that alter e-mails to insert link tracking, remove or replace common e-mail headers, including trace headers, focus on e-mail marketing or simply do not perform to our expectations. The services below are ones we either use or would use ourselves, based on price, performance and features.

While we were not evaluating marketing services, we did look at Moosend and found their support to be very responsive. You may wish to consider them if you are looking for marketing services specifically.

Most users of our software prefer to use an SMTP relay (often referred to as a smart host), as this avoids the complexities associated with running your own e-mail server. Relay services typically only require adding a few simple CNAME records to DNS. In contrast, running your own server requires not only creating DNS entries yourself for SPF, DMARC and DKIM, but the DKIM public/private key pairs as well. Do you really want to learn about public-key cryptography?

You will also want to ask your service provider to configure a PTR record for your IP address or set a PTR delegation for IPv6, and make sure your hostname matches the IP PTR record.

All of the above is just the minimum for reliable delivery. If your IP reputation is poor (e.g. with cheaper VPS hosting solutions that are often exploited by spammers), you’re going to have ongoing issues with delivery regardless of how closely you follow best practice.

Fortunately, when using SMTP relays, most of the complexities become someone else’s problem.

Another common reason users are looking for SMTP relays is to use the scan to e-mail function of their copers or multi-function printers that don’t have OAuth2 support. The services we recommend will all work with such products as they support SMTP AUTH PLAIN and/or LOGIN authentication.

Currently, we are recommending the services below for transactional or business-focused e-mail.

InterServer is recommended for advanced users who require VERP support as it is the only service on the list which supports this functionality. It is also the only service that does not force users to use their DKIM signing, allowing you to maintain exclusive control over the private keys that can sign on behalf of your domain.

Unlike other providers on this list, InterServer does not offer a free plan. Instead, they charge $1 per month and $0.20 per 1,000 e-mails. Despite the absense of a free plan, with their exceptionally low volume costs, InterServer is likely to be the cheapest solution for users who cannot get by on the limited free offerings of other providers. Their subscription model and human verification when signing-up for their e-mail service also discourages spammers, so their IPs are less likely to be blacklisted.

In addition to SMTP, InterServer provides a range of hosted solutions, including Web hosting, virtual private servers and storage servers, all at reasonable prices.

Support was very responsive, fixing a minor issue we noticed with the Web interface less than an hour after indicating a developer would investigate.

To use their SMTP service, first create an account and order the MailBaby service.

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Visit InterServer

AhaSend offers 1,000 free e-mails per month. Subscriptions start at $5 per month for 10,000 e-mails.

Additional e-mails are a flat rate of $0.50 per 1,000, making AhaSend one of the cheapest options available.

Support were very responsive and their response lead to us discovering a previously unknown bug in CMail that caused authentication to fail with their service.

Requires domain verification, via CNAME records for SPF and DKIM.

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Visit AhaSend

We’ve been recommending SMTP2Go to users since 2019 and the service continues to be actively used by clients of ours. Support is responsive and e-mail delivery is reliable.

SMTP2Go offers 1,000 free e-mails per month. Subscriptions start at $10 per month for 10,000 e-mails. Annual pricing is also available.

Additional e-mails cost between $0.50 and $1 per 1,000, depending on the subscription.

Unlike most providers, SMTP2Go allows users to send from any verified e-mail address in addition to veified domains. They also offers text messaging from $0.012 per message for paying subscribers.

Requires either sender verification to send from any address, or domain verification, via CNAME records for SPF and DKIM.

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Visit SMTP2Go