When Bubble.io first came out, most low-code/no-code solutions focus only on building internal tools for corporations. Bubble.io instead target a really broad set of website: general-purpose, customer facing product. The Bubble.io team might or might not know this, but this different tactic urged in the start of a new movement in software engineering: use Low-code/No-code tools to build Minimum Viable Products.
Nowadays, Bubble.io is one of the most prominent players in the field of No-code/Low-code development. Its popularity is owed to the fact that Bubble.io has a really beginner-friendly learning curve. Bubble.io abstract out the most tedious part of web development: the communication between frontend and backend. In fact, building application with Bubble.io feels just like building a native, single machine application.
Bubble.io is a low-risk/low-cost tool that enables tech entrepeneur to test out their ideas. A full-fledged manifestation of their idea can be fleshed out in matter of days, which can be then put out to the market to test their viability. Bubble.io enables entrepeneurs to approach their product in a very LEAN way, lowering the entry level of building a tech product.
To better understand what Bubble.io is, CitizenDev has published a comprehensive analysis of the platform. You can read it here!