What it is: Pay for compute resources by the second/minute/hour with no long-term commitment.

What it’s for:

• Short-term, spiky, or unpredictable workloads.
• Testing, dev environments, temporary projects.

Key ideas:

• Highest flexibility, usually higher price than commitment models.

Exam cues:

• “no commitment needed” → On-Demand.
• “workload is unpredictable” → On-Demand (or Auto Scaling).

Hard words:

• *commitment* /kəˈmɪtmənt/: cam kết
• *spiky* /ˈspaɪki/: tăng vọt theo lúc
• *unpredictable* /ˌʌnprɪˈdɪktəbl/: khó dự đoán