Well-Architected Tool and Review Process

The AWS Well-Architected Tool is a free service in the AWS Management Console that helps you review your workloads against AWS best practices. You answer a series of questions about your architecture across the six pillars, and the tool generates a risk report identifying High Risks (HRIs) and Medium Risks (MRIs) with specific improvement recommendations. Think of it as a structured conversation between you and the Well-Architected Framework — the questions guide you to think critically about every aspect of your architecture.

The first step in using the Well-Architected Tool is defining a workload — a collection of interrelated AWS resources and code that make up your application or service. Be specific: a workload might be your order processing microservice, not your entire company's AWS account. Define the environment (Production, Pre-Production, Development), the AWS regions used, and the industry for relevant compliance context. Well-defined workload boundaries make the review questions more relevant and actionable.

For each pillar, the Well-Architected Tool presents a set of questions with multiple best practice options. For example, for the Reliability pillar: How do you back up data? — best practices include automated backups, cross-region copies, and recovery testing. You select which practices you have implemented, and the tool calculates risk based on gaps. Questions are designed to be challenging — most workloads will have gaps, which is the point: the tool reveals what to work on next, not to fail you.

The Well-Architected Tool classifies findings as High Risk (HRI) or Medium Risk (MRI). An HRI indicates a significant gap that should be addressed immediately — for example, not encrypting sensitive data at rest or running production workloads without backups. An MRI is a notable gap that should be addressed on a roadmap. Questions with no issues are marked No Risk. Aim to resolve all HRIs before addressing MRIs. The tool also distinguishes questions you have not yet answered as Unanswered.

For each identified risk, the Well-Architected Tool provides an improvement plan with specific, actionable recommendations and links to relevant AWS documentation. You can mark improvement items as in-progress or completed to track remediation progress over time. Prioritise improvements based on risk level and business impact. The improvement plan output can be exported and used as a technical roadmap or presented to leadership to justify architectural investments.

Milestones are snapshots of your workload review at a point in time. Save a milestone before and after making architecture improvements to track progress. The Well-Architected Tool lets you compare milestones to see how your risk profile has changed — for example, how many HRIs you resolved in the last quarter. Milestones are essential for demonstrating continuous improvement to compliance auditors, management, and customers. Create milestones before major releases and after completing improvement sprints.

Beyond the default Well-Architected lens, AWS provides Custom Lenses for specific domains. The Serverless Lens has questions specific to Lambda, API Gateway, and event-driven architectures. The SaaS Lens covers multi-tenant isolation and onboarding. The Data Analytics Lens focuses on data lakes and streaming. You can also create your own custom lens with your organisation's specific standards and best practices. Apply multiple lenses to the same workload for comprehensive coverage.

Large organisations with hundreds of workloads cannot review each one manually. AWS Well-Architected Tool integration with AWS Organizations allows central teams to share workloads and review profiles across accounts. AWS Partners (AWS Solutions Architects and APN Consulting Partners) can conduct formal Well-Architected Reviews for customers and access a special review mode. Use the Workload Sharing feature to grant read or owner access to other AWS accounts for collaborative reviews.

Well-Architected reviews should not be one-time events — integrate them into your software development lifecycle. Recommended cadence: Before launch — conduct a review when designing a new workload. Quarterly — update the review as the workload evolves. After major incidents — a post-mortem may reveal new gaps to add. After AWS service launches — new services may offer better solutions. Treat the Well-Architected Tool as a living document of your architecture's quality, not a checkbox exercise.

The SAA-C03 exam frequently tests Well-Architected Framework knowledge through scenario questions that ask which pillar a given situation or solution belongs to. Key mappings to memorise: Operational Excellence — IaC, runbooks, post-mortems. Security — least privilege, encryption, GuardDuty. Reliability — Auto Scaling, Multi-AZ, health checks. Performance Efficiency — caching, right-sizing, Graviton. Cost Optimisation — Spot instances, Savings Plans, lifecycle policies. Sustainability — Graviton, managed services, eliminating waste.

To run a Well-Architected review: 1) Define your workload in the tool. 2) Select applicable lenses. 3) Answer all questions — be honest about what you have NOT implemented. 4) Review the risk report — prioritise HRIs. 5) Create an improvement plan with owners and deadlines. 6) Save a milestone to record the starting state. 7) Implement improvements and update question answers as you go. 8) Save a new milestone to track progress. Repeat quarterly. An honest, complete review is more valuable than a perfect score with omissions.

Test your understanding of AWS Solutions Architect (SAA-C03) concepts from this lesson.

In this lesson you learned: the Well-Architected Tool evaluates workloads across six pillars and generates HRI/MRI risk findings, milestones capture progress snapshots for tracking improvement over time, and custom lenses extend reviews to serverless, SaaS, and data analytics domains. Integrate reviews into your SDLC as a living quality assessment. Next up we explore cost optimisation techniques including right-sizing and Compute Optimizer.