Agile là gì?

Agile emerged from the 2001 Agile Manifesto, a document signed by 17 software developers that articulated four core values: individuals and interactions over processes and tools, working software over comprehensive documentation, customer collaboration over contract negotiation, and responding to change over following a plan. These values were a deliberate reaction to 'waterfall' project management — the sequential model where requirements are fully specified upfront, then designed, built, and tested in phases — which routinely produced software that took years to deliver and was already obsolete by the time it shipped.

Agile is a philosophy, not a specific methodology. The most widely used methodologies built on Agile principles include Scrum (work organized into 1–4 week sprints with defined ceremonies: sprint planning, daily standups, sprint review, and retrospective), Kanban (a continuous flow model with visual task boards and work-in-progress limits), and SAFe (Scaled Agile Framework, for large enterprise programs). Scrum is by far the most common in software teams; Kanban is popular for operations and support workflows; SAFe is used in complex multi-team programs.

The practical mechanics of Scrum involve: a Product Backlog (the prioritized list of all work to be done), a Sprint Backlog (the subset of work committed to in the current sprint), a Definition of Done (the criteria that must be met for a work item to be considered complete), and regular retrospectives to continuously improve the team's process. The goal is to produce a working, demonstrable product increment at the end of every sprint — enabling rapid feedback and course correction.