I wanted to share my findings, rather than my code at this stage, and here are my Top 5 SendGrid tips:

1. Do review Microsoft’s guide on how to get started with SendGrid via Azure, this simple article gives you a great base on how to set up the back-end and start writing C# around it: https://docs.microsoft.com/en-us/azure/sendgrid-dotnet-how-to-send-email
2. Use Unsubscribe groups – these allow you to stay within GDPR in Europe, appending an Unsubscribe and Manage Preferences link to the bottom of the emails that are sent. i.e.

3. Write both plain text and HTML content for your email, I ended up creating an HTML builder so I could convert Email addresses to <a href="mailto:EmailAddress"> and any HTTP(s):// links to <a href:"http://link"> this was a great experiment with regular expressions. Note, I found that not all Email clients auto-convert, e.g. Outlook will convert an Email address but not a URL. I was creating my body text in a Rich Text Box, so it was just one big string!
4. Look into Personalisations (https://sendgrid.com/docs/for-developers/sending-email/personalizations/) these are crucial if you want to customise your output (the emails themselves). I created variables to use in subject and body lines so I could pass in {customer} and {product}. SendGrid has a substitution capability which comes as part of personalisation. I’ll share a snippet of code here, as I found a solution on StackOverflow (https://stackoverflow.com/a/53292550) but it needed a slight tweak, changing the Tos.Add to a msg.AddTo as the To: Email address needs to be a part of the personalisation, I wasn’t sure if this was to do with API changes or not! Another tip, if you want the subject to be the same, without substitutions you can use the SetGlobalSubject method

var personalizationIndex = 0;
                foreach (var subscriber in subscriberEntities)
                {
                    msg.AddTo(new EmailAddress(subscriber.RowKey, subscriber.Name), personalizationIndex);
                    msg.AddSubstitution("{product}", product.Description, personalizationIndex);
                    msg.AddSubstitution("{customer}", subscriber.Name, personalizationIndex);
                    personalizationIndex++;
                    
                }

5. Create a test email method, that uses the same logic as your core one, but only sends to one email address. You don’t want to be sending bulk emails out without checking them first!

I hope this new style of thread has been an interesting read, I hope to do more very soon!

5 Useful SendGrid Tips