Behind Salesforce's flexibility is the Apex and Lightning ecosystem. When the standard features aren't enough, coding is done with platform-native tools.
01. Apex: A Java-Like Language
Salesforce's server-side language. Triggers, batch jobs and REST endpoints are written with Java-like syntax. It has multi-tenant limitations (governor limits).
02. Lightning Web Components (LWC)
A UI framework based on the modern web-standard web components. A React/Vue-like component model, deeply integrated into the Salesforce ecosystem.
03. SOQL and SOSL
SOQL: a SQL-like query language. SOSL: full-text search. Paths of direct access to the Salesforce database.
04. DevOps: Salesforce DX
A modern development experience: source-driven development, scratch orgs, CI/CD pipeline, Git integration.
05. Publishing on AppExchange
You can publish an application you've developed on AppExchange. There are security-review, listing and revenue-share processes.