Running Business Systems on AWS: A Primer for Reading Vendor Quotes

AWS (Amazon Web Services) is Amazon's umbrella term for its cloud computing services, letting businesses rent computing power and storage over the internet instead of buying and maintaining physical servers. Many custom-built or outsourced business systems run on cloud platforms like AWS. Business owners don't need to operate AWS themselves, but understanding the basic terminology that appears in quotes and proposals makes it much easier to have informed conversations with development vendors and judge whether costs are reasonable.

Quotes for AWS-based systems often list many service names, but they generally fall into four functional groups. The table below summarizes each role and the representative AWS service typically used for it.

The virtual server (compute) is where the system's program actually processes requests. Where companies once needed physical servers on-site, AWS lets you provision the required capacity in minutes and scale up relatively easily as traffic grows. The database organizes and stores customer records and order histories so they can be searched and aggregated on demand, typically reducing the burden of backups and failure recovery compared to self-managed infrastructure. File storage holds images, PDFs, and system backups, usually billed based on the volume stored. Network and security settings protect these components from unauthorized external access, and this work is often itemized as "initial build cost" in vendor quotes.

Recent quotes sometimes mention "serverless" architecture. Instead of keeping a virtual server running at all times, this approach only executes processing at the moment a request actually arrives. For small internal systems with light traffic, or tools used only during certain hours, this can reduce monthly costs since there's no charge for idle time. On the other hand, systems with consistently heavy traffic or strict response-time requirements may be better served by a traditional server setup; which approach fits depends on actual usage patterns. It's worth asking your development vendor why they chose a particular architecture and whether it matches how your organization actually uses the system.

- Instance: a unit representing one virtual server, often labeled with a performance tier such as "t3.small"
- Region: the geographic location of AWS's data centers; services aimed at Japan typically use the "Tokyo region"
- Pay-as-you-go billing: a pricing model where costs scale with actual usage — more traffic or data means higher costs
- Redundancy: a design where duplicate systems are set up so that if one fails, the other keeps running
- IaC (Infrastructure as Code): managing server configuration through code, reducing manual errors and making rebuilding easier

When these terms appear in a quote, asking "why was this chosen?" and "how does the cost compare to alternatives?" deepens your understanding of the proposal. You don't need to memorize the terminology itself — what matters is understanding how each choice affects cost and timeline. For a broader rundown of what to confirm before signing a contract, see the pre-order checklist.

AWS usage fees are billed on a pay-as-you-go basis determined by a combination of server performance, uptime, data volume, and network traffic, so costs vary widely even among systems that are all called "business systems." As a general tendency, a small internal system used by a few dozen people might run roughly a few thousand to 20,000 yen per month, while a mid-sized system that also serves customers might run roughly 20,000 to 100,000 yen per month — but these are only rough indicators, and actual costs shift with exchange rates and AWS's own pricing changes. For accurate figures, use AWS's official Pricing Calculator or obtain quotes from multiple development and operations vendors for comparison.

These figures indicate general tendencies only; actual costs depend heavily on usage and configuration. Before signing any contract, always verify current figures using AWS's official pricing calculator and quotes from multiple vendors.

- Who monitors month-to-month changes in AWS usage fees and alerts you to unusual spikes?
- Does the maintenance contract cover applying security patches and updates?
- What is the escalation process and target recovery time in the event of an outage?
- How often are backups taken, and is restoration actually tested?
- Could a different vendor take over maintenance if needed, or is the system locked to one company (avoiding vendor lock-in)?

A system running on AWS isn't a "build it and forget it" project — it requires ongoing operation and monitoring. For a detailed look at what maintenance contracts should cover and how to think about cost, see the complete guide to system maintenance. To assess how much your organization stands to gain from moving to the cloud, the SMB guide to cloud migration and migrating to AWS or Azure are also useful references.

AWS is a leading example of the cloud infrastructure that underpins business systems, and it becomes much easier to understand once you organize it into four roles: virtual servers, databases, file storage, and networking. Business owners don't need to manage the details themselves, but understanding the terminology in quotes and the fact that costs vary with usage makes conversations with vendors and decision-making considerably easier. Always confirm current figures using the official pricing calculator and quotes from multiple vendors before making a final decision.