Tabnine watches what you type and suggests the next line of code in real time, much like autocomplete on your phone. It works inside popular IDEs (VS Code, JetBrains, Vim) and learns patterns from your codebase to make suggestions smarter over time. The core differentiator is local execution: your code never leaves your machine, which matters if you're working with proprietary or sensitive projects. The free tier covers single-file suggestions; the paid plan (roughly $15/month for individuals, higher for teams) unlocks multi-file context and deeper learning. The trade-off: on massive codebases, even local processing can bog down your editor.