Accessing old SOAP API without hammering it completely

I'm working on a project that accesses an old SOAP API( European Criminal Records Information System (ECRIS)).

This particular instance of ECRIS is fairly old, updated last, to my knowledge in 2005-ish.

The goal is to sync some changes every X amount of time. From the api to another machine(s).

The synced data is a bunch of judicial dossiers that get updated after various judicial processes happen. The data is more of an append only ledger, since everything must be kept on record. Nothing particularly challenging from this point of view.

Now, the issue is that the only real way to get a specific dossier is by a unique dossier number. Singular. Yes, you can only query a dossier number at a time.

Obviously this is an issue since there can be thousands, if not hundreds of thousands, of dossiers to keep track off.

The only saving grace is that there's another param, lastModifiedDateStart, that I can add to filter dossiers that have changes from a certain date forward. If there are no changes the response is pretty fast...at least testing it seems to be.

There's Z E R O chance that this api will change anytime soon. That particular ECRIS system is an ancient behemoth that serves an entire country's worth of judicial records.

My only concern now is not hammering the api and getting banned or something.

What I came up with so far is

• serving local records whenever possible(no brainer)

• obviously using the date filter. BUT this filter needs to be backdated at least 7 days. Why you ask? Because clerks have the habbit of entering records on Monday backdated to Friday. Not really and issue legally, just a pain in the ass to deal with. Oh...and sometimes on long vacations they may enter updates from a dossier backdated to a few weeks. This ALSO pain in the ass because 7 days would not be enough.

• spreading out the queries throughout the day in batches of 100 or something. Basically having the workers run non stop.

• I'm seriously considering running a VPN to another city in the same country so I can have a different instace of workers be able to run. This less about hammering the API and more about actually getting the data required

• dossiers have no real end date, as updates can happen decades after. Imagine an old murder getting solved.

I'm really hoping you guys and girls can come up with better ideas than me.