crypto_vba VS VBA-JSON

It basically uses the Dictionary object to create variables (e.g. with a dictionary in a dictionary) and after that using that library to transform it into a string. I'm using it in my project here: https://github.com/krijnsent/crypto_vba/blob/master/ModExchKucoin.bas

I agree with u/sslinky84 that there is no safe place in VBA. The main question is: what's the purpose of an API key in this case? From your description you are not linking an API-key to a single user, but have "one key to rule them all". So you probably want to prevent someone from grabbing your end-point and spamming it? In that case you're perfectly fine in creating one API-string in VBA and checking that on the server: it blocks the person who is opening a browser to fiddle with your end-point, but it does give you some security. The people who can get through are the ones that manage to crack open your VBA (assuming you have a password on the VBA). To make their life a bit harder you could instead of a "fixed string" as API key go for some kind of hash, as u/archn suggests. E.g.: take the rest of the post message that e.g. also includes a mandatory timestamp, make a simple hash of that (might even include a "fixed key", see e.g. https://github.com/krijnsent/crypto_vba/blob/master/ModHash.bas for some code).

I've built an open source VBA-Excel library to communicate with cryptocurrency exchanges ( https://github.com/krijnsent/crypto_vba ) and have my code available as .bas and in an .xlsm file. A couple of days ago someone posted an issue that my xlsm file triggered a Windows defender alert. At my pc this doesn't happen, the AVG virus scanner also won't show anything.

I am mainly using Cryptocompare, but if you want to use CoinGecko, check out my code, it has the basics: https://github.com/krijnsent/crypto_vba/ It has most of the essentials: connecting Excel to web, handling Json and some API examples.

I am the creator of the Excel macro-enabled file; it has a bunch of in-built windows references being used & an external JSONConveter module (https://github.com/VBA-tools/VBA-JSON/blob/master/JsonConverter.bas). These references & json module have been in the file since a long time. Until today I didn't receive any sorts of warnings for my xlsm files, all of a sudden "Severe" warnings are popping up for all copies I have of this file. Haven't noticed this virus error so far in any of my users' PCs.

Integration of user-created modules to assist https://github.com/VBA-tools/VBA-JSON/blob/master/JsonConverter.bas

There is also a VBA-JSON library you might look into. It processes the JSON to a series of dictionary/collection objects.

the JSON parser came from this: VBA-JSON

Have you tried the VBA-JSON library? That includes a method that will format your JSON files with indenting, etc. As for styling the output, that again can be done with VBA. I did something just like this a few years ago, I can look for the code if you're interested.

I've used this https://github.com/VBA-tools/VBA-JSON in the past with VBA which may work for your case and it had issues if it was very complicated json but for things like web services worked fine for me

I've done something similar using a HTTP request and a JSON converter module.

If you're comfortable with VBA, you might want to check out VBA-JSON.