Mailgun

I use several different email service providers, each for a different reason. I use Mailgun almost exclusively for inbound mail processing. The inbound processing also offers a preliminary spam filter so that at least most of the spam isn't sent further down my process chain.

It's super easy to set up inbound routes using specific strings or wildcard matches that will accept mail and forward to multiple different recipients. These recipients can be either proper email addresses or webhook endpoints.

I often use the address forwarders in combination with the SMTP outbound service to build a system where Gmail users can use their free gmail.com account to receive and send emails from their small business domain without having to sign up for and configure a proper G Suite account.

I use the webhook forwarders in combination with Zapier and Integromat to receive any emails that need to be processed and automatically acted on. Mailgun normalizes all the different types of email and attachment encodings and packages the message data into an easy-to-parse JSON package that makes it super easy for me to grab what I need and reliably act on the normalized data.

Outside of them changing their payment tier / plan system I haven't had any issue with Mailgun. I always found their customer service great and the product itself to be fantastic and does exactly what it's supposed to. I just really wish they brought back the routing feature to the free tier.

Unreliable. The one thing that an email services cannot be.

Mailgun was one of the most developer-friendly transactional email service providers previously until they removed their free plan. However, the ease of implementation and support by different plugins and software make it a really good tool. DNS is easy to configure so we have no issue with deliverability. The dashboard is also great and offers good logs and graphs.