In my opinion, platformo can be used to mean that kind of platform, too.
The "komputada leksikono" defines it as
Kombino de komputilo (aparataro) kaj operaciumo.
which, while IT-related, is probably too narrow to include your intended usage. But "komputada leksikono" is a bit dated now and komputeko seems to use platformo in as wide a sense as "platform" is used in an IT context in English nowadays, too. (I.e., including web platforms, development platforms, publishing platforms, etc.)
- Apple platform (s) — Apple-platformo
- closed platform (walled garden, closed ecosystem) (s) — fermita platformo
- cross platform (cross-platform) (a) — plursistema
- crowdfunding platform (s) — amasfinanciga platformo
- graphics platform (s) — grafika platformo
- platform (s) — platformo KompLeks ; soklo [FF]
- publishing platform (s) — publikiga platformo
I think the definitions for platformo in PIV
- Plialtigita ebena maso el teraĵoj, roko, cemento ks, sur kiu oni starigas baterion de kanonoj.
- Plata ebena parto de ŝipkonstruaĵo, sur kiu oni starigas la kanonturetojn, aŭ sur kiu oni aranĝas alteriĝan areon.
- Plata parto de vagono, aŭtobuso aŭ tramveturilo, kie la pasaĝeroj restas stare.
- Deklaraĵo, prezentanta la politikan programon de partio, okaze de balotado.
are much too narrow, and this might even be the reason why PIV needs so many of them: The first three have in common that they all describe (probably artificial) flat, level surfaces. All four have in common that they can support something, that one can either stand on them or build upon them. Like the direct meaning of the English word "platform" they're a kind of fundament that is mostly independent of what you put on top of it. (And the ones building or standing on top of it, might be others than the ones who provide or built the platform.)
As a metaphor, this works for all kinds of "platforms" in IT, business and other fields. And the entries in komputeko indicate that this metaphor is indeed used also in Esperanto.
By the way, the German word "Plattform" is also used that way (with mostly the same direct and metaphorical meanings) and I guess similar corresponding words in other related languages are used similarly, too. Note though that the German word "Plattform", other than the English one, cannot mean a train station platform (the area from which passengers board the trains). That'd be a "Bahnsteig".