I would suggest against this if you don’t know what you are doing. Dealing with email deliverabolity and reputation is a nightmare. Talk to someone at sendgrid/mailgun/mandrill/etc and focus on more important parts of your service.

How will that affect my relationship with Sendgrid?

Preemptive being checking the emails before they go out for malicious links etc, and reactive being checking the deliverability (delivered, bounced) as well as optionally email actions (open, click, ubsubscribe, flag) and stopping the account from sending further emails if something bad is happening.

This last part "blocking the account" is what will save you from waking up one sunday morning to find out your domain has been added to all spam lists and no one wants your emails any more. -- This can be even done on a per-sending-account basis. ie Each of you clients can have their own subaccount in these providers and only the infringing account will be impacted.

Badges: When you send an email, you're sending to the recipient's email server--gmail.com or whitehouse.gov or whatever. But these servers get a billion spam messages a day, so you need to prove you're really boeing767.com, else most of your messages will get flagged as spam. This is typically done by adding SPIF and DKIM (special DNS records) for whatever domain you use, e.g. boeing767.com

Chatgpt can pretty much write the code do this this (or get you up to speed on how it all works) if you don't want to spend a bunch of time on it.

And confidently get it wrong in this case. This is an example of why ChatGPT and others like it need a debug function to show their work/sources. Can you spot the errors and missing data?