Tying a unique id from my application

Hey there! Just figuring out the easiest use case for myself, I think given the existing endpoints I could probably cobble a solution together, but wanted to ask the pros.

My application functionally does the following

fetches a templated document id
fetches the mailing list template (for the mapping id)
generates and uploads a new mailing using the mapping information from the previous step
creates and submits a job.

All of that is working fantastically, but I'm wondering if there's a step in this process where I can attach a unique identifier from my application so I can query the tracking status and provide an update to my application on the documents current status.

I could use the job tracking details and the address record, but after CASS correction I get wobbly about comparing my user inputted data to the standardized address. I could do some levenstein or string analysis but that's tricky with addresses.

I could also get clever with putting inside of merge fields and functionally using the unused field to tie it to an entity.

Just wondering what best practices are with the API for this use case.

Thank you!