In this small tutorial I will show you howto use mailjet as a free SMTP service for Discourse.
At the moment mailjet let you send 6000 mails per month or 200 per day for free and without sharing your credit card information.
Signup
You can sign up here Mailjet - Sign up (not a affiliate link)
Then validate your account by clicking the link in the email.
Create your domain
Go to your account settings: Mailjet
Press “Add a Sender Domain or Address”
Then add your domain
(Please note that to validate a domain, you need to have access to your website hosting or your domain registration account.)
Adding a new domain
DNS verify your domain
Login to your DNS host.
Add a new DNS record based on the info from mailjet
Add the new TXT DNS record to you DNS service. In this case cloudflare.
End the validation by returning to your mailjet window. And press Check Now
You’ll see a window like this when you’re done
Setup SPF Authentication
Under Mailjet “Sender & Domain” you find this option
Make a new TXT DNS record with the recommended settings:
After this you should get a green setting window
Set up DomainKeys/DKIM
Make a new TXT DNS record
Please make sure it stays on one line!
Setup Your Username and Password
First you need to generate your secret key, this will eventually be your SMTP Password. To do this go to API Key Management page.
On this page you see that your API Key (this will be your SMTP username) is created but partially redacted, but your Secret key needs to be generated:
Click the Generate Secret Key button. This will give you a new modal screen which contains your API Key and Secret Key. Copy these into a safe place as you’ll need them in the next step. If you lose your Secret Key you’ll need to regenerate it and setup Discourse SMTP again.
With that generated you can now visit the MailJet SMTP and SEND API Settings page to grab the rest of the settings you’ll need.
Installation of Discourse.
In the initial setup of discourse, use the following settings:
- SMTP Server Address = MailJet SMTP server
- SMTP Port = SMTP port it will be 25 or 587, note that some providers block port 25.
- SMTP Username = MailJet API Key you copied.
- SMTP Password = MailJet Secret key you copied.
Your setup will look similar to this:
Then you should be done and ready to use the service. 
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