A Step-by-Step Checklist for Reviewing an Early-Stage SaaS Architecture in 2 Hours

Early-stage SaaS teams rarely have the luxury of week-long architecture reviews.

You are shipping features, chasing product-market fit, and trying to keep the system from collapsing under the first real wave of users. At the same time, you do need to understand whether the architecture you have today can survive the next 12–18 months.

A short, focused 2-hour architecture review can give you just enough signal to decide:

• where the real risks are,
• what is "good enough for now",
• and where a bit of early investment will save you a lot of pain later.

This article lays out a step-by-step checklist you can use for that 2-hour session.

It is not a full audit. It is a deliberately constrained way to get an honest snapshot of an early-stage SaaS architecture without turning it into a ceremony.

What a 2-Hour Architecture Review Is (and Isn’t)

Before diving into the steps, it helps to set expectations.

A 2-hour review is:

• a structured conversation with the people who actually change the system,
• a way to surface risks and trade-offs that are already present,
• a tool to align founders, product, and engineering on where to invest next.

It is not:

• a replacement for ongoing architecture practice,
• a chance to redesign everything from scratch,
• a gatekeeping exercise or status meeting.

Going in with the right framing makes it much easier to stay honest and avoid turning the session into a debate about the perfect future platform.

Preparation: What to Bring Into the Room

You can spend the full 2 hours live, but a little preparation makes the session dramatically more useful.

Ask one person (often a lead engineer) to collect, ahead of time:

• Current architecture diagram – even if rough. Boxes, arrows, main flows.
• Key user journeys – 2–3 flows that really matter today (e.g., sign-up, key transaction, reporting).
• Basic traffic and growth expectations – current monthly active users, target for the next 12–18 months.
• Team context – who works on what, on-call setup, and any big upcoming hires.

The goal is not perfection. It is to avoid spending half the session rediscovering information everyone already knows.

0–15 Minutes: Clarify Context and Constraints

The first 15 minutes are about anchoring the conversation.

Checklist:

• Business stage

  • Where are you on the journey: pre-product-market fit, early traction, or scaling a proven product?
  • How long is your current funding runway?

• Product promises

  • What have you implicitly promised users? (e.g., "always on", low latency, strong data privacy.)
  • Are there explicit SLAs or compliance requirements?

• Team and skills

  • How many people can realistically work on the system in the next 6–12 months?
  • Which critical skills are scarce (e.g., deep database expertise, Kubernetes, security)?

By the end of this slice, you want a shared answer to: "Good architecture for this company, over the next 12–18 months, means what?"

15–35 Minutes: Map Critical Flows and Boundaries

Next, you zoom in on the pieces of the system that matter most today.

Checklist:

• Pick 2–3 critical flows

  • Sign-up and onboarding.
  • The primary value-creating action (e.g., creating a workspace, sending a campaign, processing a payment).
  • One reporting or analytics path users care about.

• Walk each flow end-to-end

  • Which services, queues, and databases are touched?
  • Where do you cross trust boundaries (internet, third-party APIs, internal admin tools)?
  • Where is state written and read?

• Mark boundaries on the diagram

  • Which parts are "core product" vs. supporting tooling?
  • Where are external dependencies you do not control?

The output is a simple but honest view of how requests move through your system today. Many problems become obvious at this stage: surprising dependency chains, single databases at the centre of everything, or critical flows that depend on a forgotten script.

35–60 Minutes: Spot Failure Modes and Operational Risks

With flows in view, you can now ask how the system behaves when things go wrong.

Checklist:

• Availability and recovery

  • If the primary database is unavailable for 15 minutes, what breaks, and how do you recover?
  • If a key third-party API starts timing out, what is the impact on user flows?

• Scaling characteristics

  • What parts of the flow are likely to saturate first (CPU, database connections, queues)?
  • Are there obvious fan-out patterns (e.g., N+1 calls per user) that will not survive growth?

• Observability

  • When something breaks, where do you look first today (logs, dashboards, traces)?
  • Can you easily see latency, error rates, and throughput for the critical flows you just mapped?

• On-call and runbooks

  • Who gets paged when these flows break?
  • Is there a runbook, even if minimal, for the most painful incidents you have already seen?

You are not trying to design the perfect SRE posture. You are trying to understand how fragile the current system is under real-world stress.

60–90 Minutes: Assess Changeability and Developer Experience

Early-stage systems fail as much from being hard to change as from being unreliable.

Checklist:

• Repo and module structure

  • How many places do you typically touch for a simple feature?
  • Is there a clear separation between domain logic, infrastructure, and UI?

• Testing and safety nets

  • What gives you confidence a change will not break core flows (tests, staging, feature flags)?
  • How long do tests take to run on a typical change?

• Delivery pipeline

  • How often do you deploy today?
  • How painful is rollback if something goes wrong?

• Local development

  • How long does it take a new engineer to set up the environment and ship a first change?
  • Are there obvious "sharp edges" people are warned about informally?

From an architectural perspective, you are asking: "Does this system let a small team make safe changes quickly?" If not, that will hurt more than a bit of extra latency.

90–120 Minutes: Prioritise Findings and Next Moves

The last half hour is where the review becomes actionable.

Checklist:

• Cluster findings into themes

  • Reliability and failure modes.
  • Scalability and performance.
  • Developer experience and speed of change.
  • Data and compliance.

• Pick 3–5 concrete issues

  • For each theme, identify one or two specific, observable problems.
  • Phrase them as sentences a non-engineering leader could understand.

• Define 3 pragmatic next steps

  • One quick win (e.g., add basic dashboards for a critical flow).
  • One structural improvement (e.g., introduce a clear separation between app and background workers).
  • One decision to revisit later, with a clear trigger (e.g., "Reevaluate database sharding when we hit X customers.").

Write these down. The real value of the review is not the conversation; it is the short list of deliberate moves you agree to make.

How to Use the Output After the Session

A 2-hour review produces a lot of insights. To avoid losing them in a slide deck:

• Turn the findings into a one-page architecture note:

  • Business context and time horizon.
  • Diagram of critical flows.
  • Top risks by theme.
  • The 3 next steps you agreed on.

• Share it with:

  • engineering and product leads,
  • founders and key stakeholders,
  • anyone who will be involved in the next significant change.

• Revisit it after 3–6 months:

  • Which risks did you actually address?
  • Which new risks appeared?
  • Does the 2-hour checklist need to change for where you are now?

Treat the review as a recurring tool, not a one-off health check.

How We Think About Early-Stage Reviews at Fentrex

When we look at early-stage SaaS architectures, we try to honour the constraints teams really live inside:

• You cannot freeze feature work for months. Reviews must fit around shipping.
• You will make trade-offs. Not every risk can be addressed immediately.
• You need clarity more than perfection. A shared mental model beats a detailed but unused diagram.

That is why we prefer short, focused reviews over sprawling redesign conversations. The goal is to:

• make current risks explicit,
• help teams choose a few high-leverage improvements,
• and create a habit of looking at architecture through the lens of how the system is actually built and operated today.

In early-stage SaaS, architecture is less about predicting every future requirement and more about making sure the system can survive the next few waves of growth without surprising you.

Questions to Ask About Your Own Early-Stage Architecture

If you want to run a 2-hour review using this checklist, a few closing questions can help you prepare:

• Which 2–3 user flows really define value in your product today?
• Where would a 30-minute outage hurt you most – and how would you notice?
• How long does it take a new engineer to ship a confident change?
• What are the 3 architecture risks you quietly hope nobody asks about?

Answering honestly is more important than having the "right" architecture.

The point of the session is not to earn a grade. It is to make sure your early-stage SaaS has a foundation that can support the product you are trying to build – for the next stage of growth, not for an imaginary end state.