What Is AWS? Amazon Web Services Explained Simply
The complete beginner's guide to AWS — what it is, what it costs, and how to get certified
Amazon Web Services (AWS) is the world's largest cloud computing platform. It provides on-demand access to computing power, storage, databases, networking, AI/ML, and hundreds of other services — all delivered over the internet and billed per use. AWS powers companies from Netflix and Airbnb to millions of startups and enterprises. Understanding what AWS is and how it works is the foundation of the AWS Cloud Practitioner certification and the starting point for any cloud career.
What AWS actually is
AWS is a cloud computing platform owned by Amazon. Rather than buying physical servers and running them in your own data centre, AWS lets you rent computing resources on demand — pay for what you use, stop paying when you stop using it. AWS operates data centres in 33+ geographic regions worldwide and makes those resources available over the internet. You access AWS through a web browser (the AWS Management Console), via command line (AWS CLI), or through code (AWS SDKs). The core idea: instead of buying infrastructure, you rent it — and you can scale it up or down in seconds.
AWS launched in 2006 with just three services (S3, SQS, EC2). Today it offers 200+ services. The core exam-relevant services are a small subset: EC2, S3, RDS, VPC, Lambda, IAM, and CloudWatch cover the majority of CLF-C02 and SAA-C03 questions.
The five types of AWS services you need to know
AWS services fall into a few major categories: (1) Compute — running code and applications. EC2 (virtual machines), Lambda (serverless functions), ECS/EKS (containers). (2) Storage — storing data. S3 (object storage), EBS (block storage for EC2), EFS (shared file system), Glacier (long-term archive). (3) Databases — managed database services. RDS (relational: MySQL, PostgreSQL, SQL Server), DynamoDB (NoSQL), Aurora (high-performance relational), ElastiCache (in-memory). (4) Networking — connecting services and users. VPC (private networks), CloudFront (CDN), Route 53 (DNS), Elastic Load Balancer. (5) Security & Identity — IAM (who can do what), AWS Shield (DDoS protection), WAF (web application firewall), KMS (encryption key management).
For the AWS Cloud Practitioner exam, you need to know WHAT each service does — not HOW to configure it. For Solutions Architect (SAA-C03), you need to know which combination of services solves a given architectural scenario.
How AWS pricing works
AWS uses a pay-as-you-go model — you pay only for what you use, with no upfront costs or long-term contracts (unless you choose them). Three main pricing models: (1) On-Demand — full price, no commitment, scale up/down freely. Best for unpredictable workloads. (2) Reserved Instances — commit to 1 or 3 years in exchange for up to 72% discount. Best for steady-state production workloads. (3) Spot Instances — bid on unused EC2 capacity at up to 90% discount. AWS can reclaim these with 2 minutes' notice. Best for fault-tolerant batch jobs. For storage, you pay per GB per month. For data transfer, you pay for data leaving AWS (egress) — data entering is free.
The most common beginner mistake with AWS is leaving resources running. An EC2 instance or RDS database that you forgot to delete will keep charging you. Always check the Billing Dashboard and set up AWS Budgets alerts before experimenting — the free tier is generous but has limits.
AWS vs Azure vs Google Cloud — the real difference
AWS, Microsoft Azure, and Google Cloud Platform (GCP) are the three dominant cloud providers. AWS has the largest market share (~31%), the most services (200+), and the deepest ecosystem. Azure is second (~24%) and is the natural choice for organisations already using Microsoft 365, Active Directory, and Windows Server. GCP is third (~12%) and has strengths in AI/ML, Kubernetes (Google invented it), and BigQuery for analytics. For certification and career purposes: more job postings cite AWS than Azure or GCP, but Azure and GCP roles typically pay similarly at mid-to-senior level. Choose based on what your target employers use.
The AWS Free Tier — what you actually get for free
AWS offers a Free Tier to new accounts for the first 12 months. Key free resources: EC2 — 750 hours/month of t2.micro or t3.micro (enough for one always-on instance). S3 — 5 GB of standard storage. RDS — 750 hours/month of db.t2.micro or db.t3.micro. Lambda — 1 million free requests per month (always free, no 12-month limit). CloudFront — 1 TB of data transfer out per month. These limits reset monthly. Always-free services (no 12-month expiry) include Lambda, DynamoDB (25 GB), and CloudWatch basic metrics. Set a billing alert immediately after creating an account.
The best way to study for AWS certifications is to build things on the free tier. Create an S3 bucket, launch a t2.micro EC2 instance, set up an IAM user with least-privilege permissions, and point Route 53 at a simple web page. Hands-on learning is faster than flashcards.
The AWS certification pathway
AWS certifications are organised in four tiers: Foundational (entry-level, no experience required), Associate (1 year experience recommended), Professional (2+ years), and Specialty (deep expertise in a specific domain). The most popular path: CLF-C02 (Cloud Practitioner) → SAA-C03 (Solutions Architect Associate) → SAP-C02 (Solutions Architect Professional). Alternatively: CLF-C02 → DVA-C02 (Developer Associate) for software engineers, or CLF-C02 → SOA-C02 (SysOps Administrator) for operations roles. The new AIF-C01 (AI Practitioner) is a foundational AI-focused cert that can be taken alongside or after CLF-C02.
Key tips
Create a free AWS account at aws.amazon.com and explore the console — hands-on time is more valuable than reading.
Set up a Billing Alert (CloudWatch → Alarms) immediately to avoid surprise charges.
The AWS Skill Builder platform (skillbuilder.aws) has free official learning paths for every certification.
AWS re:Invent talks on YouTube are free and cover every service in depth — great for audio learners.
The AWS Well-Architected Framework (five pillars: operational excellence, security, reliability, performance, cost) is tested on SAA-C03.
Frequently asked questions
What is AWS?
AWS (Amazon Web Services) is Amazon's cloud computing platform. It provides on-demand access to computing, storage, databases, networking, AI/ML, and 200+ other services over the internet, billed on a pay-per-use basis. AWS is the world's largest cloud platform with ~31% market share.
What does AWS stand for?
AWS stands for Amazon Web Services.
What is AWS used for?
AWS is used for hosting websites, running applications, storing data, processing analytics, training AI/ML models, sending email, managing CDN delivery, building serverless functions, and almost any computing workload. It powers Netflix, Airbnb, Reddit, NASA, and millions of other organisations.
Is AWS free?
AWS has a Free Tier for new accounts covering 12 months of limited free usage on most services (EC2, S3, RDS) and permanently free tiers for some services (Lambda, DynamoDB, CloudWatch basics). Beyond free tier limits, AWS charges per use. Always set up billing alerts to avoid unexpected charges.
AWS vs Azure — which is better?
Neither is universally better — choose based on your organisation's ecosystem. AWS has the largest service catalogue and market share. Azure integrates deeply with Microsoft 365, Active Directory, and Windows Server — making it the natural choice for Microsoft-heavy organisations. For career purposes, AWS has more global job postings, but both command comparable salaries.
How do I get started with AWS?
Create a free account at aws.amazon.com, enable MFA on the root account, set up a billing alert, and start exploring with the free tier. The AWS Cloud Practitioner (CLF-C02) certification is the standard starting point for building structured knowledge.
What is the easiest AWS certification?
AWS Certified Cloud Practitioner (CLF-C02) is the easiest AWS certification. It costs $100, takes 90 minutes, and tests conceptual cloud knowledge only — no hands-on skills required. Most candidates pass with 20–40 hours of study.
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