Most growing companies end up with the same shape of problem. There is a CRM holding prospects, a spreadsheet holding invoices, a shared folder holding contracts, an HR tool holding staff, and a project tracker holding the work. Each one was a reasonable choice on the day it was bought. Together they hold six versions of the same customer, and nobody in the building can say which one is right.
The usual answer to this is integration. You connect the tools together, sync them overnight, and accept that at some point the sync will fail quietly and nobody will notice for a fortnight. Integration is not wrong, but it is worth being honest about what it is: a permanent agreement to maintain copies, plus the machinery that keeps the copies from drifting, plus the person whose job quietly becomes watching that machinery.
This platform takes the other answer. There is one database. Every App writes into it, and every App reads out of it. There is no sync because there is nothing to sync.
What that changes in practice
A customer is one record. When your sales team corrects a phone number, the invoice that goes out next month carries the corrected one. Not because a synchronisation ran, but because there was never a second number. The invoice was reading the same row the whole time.
A person is one record. Somebody who works for you is an employee in HR, an assignee in Projects, an approver in Invoicing and a name in the audit log. Those are four different roles played by one row. When they leave, removing their access removes it everywhere at once, which is the moment most companies discover how many separate accounts they had been quietly maintaining and how many of them belong to people who left years ago.
A file is one file. A contract attached to a customer in CRM is the same file the invoice references and the same one the asset register points at. Version confusion between departments is not solved by better naming conventions. It is solved by there being one copy.
A number is one number. The balance a customer owes is computed from the same rows the invoice list is computed from. Two screens showing that figure cannot disagree, because there is no second calculation to disagree with.
The part that is harder than it sounds
One database only works if the separation between companies is absolute, and that is the actual engineering work behind the idea.
Every business row on this platform carries a workspace identifier. Every read is filtered by that identifier before the query reaches the database, and the filter is applied by the framework rather than written out by hand on each screen. The distinction matters more than it sounds. A rule written out by hand on four hundred queries is a rule somebody eventually forgets on one of them, and that one is a leak nothing will report, because the screen still works perfectly.
Applied centrally, it is one rule that is either right or wrong. It is right, it is tested, and it is the reason the convenience above is safe to offer.
What it does not mean
It does not mean you have to use everything. Apps are turned on per workspace, and an App you have not turned on is not there: no menu entry, no settings page, no half configured module waiting to confuse a new starter. Two companies on this platform can look like completely different products.
It does not mean the Apps are shallow. Each one is a full application. Sharing a database is what allows them to be deep without duplicating each other, because none of them has to build its own version of a customer, a person, a file or a currency.
It does not mean you are locked in. Your data is yours and it exports. A platform that keeps you by making leaving painful has stopped competing on the product.
Where the boundary honestly is
Some things sit outside. A payment processor is outside. A signing tool may be outside. Your email is outside. Where a step leaves the platform it needs a connection, and a connection can break in the way described at the top of this post.
We would rather point at that boundary than pretend it is not there. What we can say is that it is a boundary at the edge of your operations rather than one running through the middle of them.
Where to start if you are evaluating this
The useful question is not which App is best. Every vendor's App is good enough for most companies most of the time.
The useful question is: which two of your current tools disagree with each other most often, and what would it be worth to stop refereeing that argument every month?