👋 Hey {{first_name|there}},
The Beautiful, Wrong Diagram
A few years ago, I led a design session for a new event-processing system.
We filled the whiteboard with boxes and arrows:
Producers and consumers
Message brokers
Retries and DLQs
Data pipelines
It was elegant.
Everyone nodded.
We took a photo, turned it into a polished diagram, and shipped it in the design doc.
Three months later, almost none of it was accurate.
One “critical” queue was bypassed entirely
The retry logic had moved upstream
The data pipeline had split into two
The system behaved differently under load than we’d modeled
The problem wasn’t that we were sloppy.
The problem was that the first diagram is always wrong.
🧭 The Mindset Shift
From: “We nailed the design”
To: “This is the starting point for learning”
Diagrams are not the truth.
They are hypotheses.
Your first diagram:
Is based on assumptions
Reflects limited knowledge
Ignores real-world constraints you haven’t hit yet
Great architects don’t defend the first diagram.
They use it to expose flaws fast, so the real design can emerge.
❌ Why First Diagrams Fail
Reality Reveals Hidden Complexity
Integration quirks, third-party limitations, unexpected latency… none of these are on the first diagram.Assumptions Go Unchallenged
If everyone agrees instantly, you’re probably missing something. Good design benefits from pushbackPeople Work Differently Than Paper
The moment a real team starts building, shortcuts, optimizations, and edge cases shift the design.Load Changes Everything
Behavior at 10 users isn’t the same as 10,000 or 10 million.
🧰 Tool: The Diagram Feedback Loop
Here’s how to make your diagrams more resilient to reality:
Step 1: Draw the First Version Fast
Don’t over-polish. Keep it rough enough that people feel free to question it.
Step 2: Invite Diverse Feedback
Get perspectives from:
Engineers who will build it
Ops/SRE who will run it
Product/PM who understands business flows
Step 3: Simulate Stress
Ask:
What breaks under load?
What if a dependency is slow?
Who owns recovery?
Step 4: Version the Diagram
Treat it like code. Version control it. Show its evolution.
Step 5: Validate in Production
The ultimate diagram is the one that matches reality, which means you’ll update it after go-live.
🔍 Example: The “Perfect” API Gateway
One team I coached designed an API gateway with:
Route-based microservices
Per-service auth
Granular caching rules
It looked perfect.
But once it went live:
The cache invalidation rules caused stale data issues
The per-service auth calls created latency spikes
Operations had to centralize some logic for faster hotfixes
The final design was simpler than the first diagram, and far more stable.
That’s the value of iteration.
🛠 Architect Behavior: Diagram as a Conversation, Not a Contract
1. Label Assumptions on the Diagram
Make it clear: “We think X will happen here”, so people know what to validate.
2. Show Alternative Paths
Add dashed lines or grey boxes for “possible future” or “plan B” scenarios.
3. Keep a “Reality Overlay”
Layer on what actually got built versus what was planned.
It’s humbling and incredibly educational.
4. Use Diagrams in Retros
At the end of a project, revisit the original diagram and note what changed and why.
➕ Advanced Tip: “Stress-Test” the Diagram in a Review
Before approving a design:
Ask the most junior engineer to walk through a real scenario using the diagram
Ask an ops engineer how they’d troubleshoot a failure in it
Ask a PM if the diagram still matches the business flow
If they struggle, your diagram isn’t ready, and neither is your architecture.
✅ Action Step: Run a Diagram Audit
Pick a design diagram you’ve made in the last 6 months.
Ask:
How closely does it match reality today?
Which parts changed and why?
Which assumptions were wrong?
Then write down what you’ll do differently on your next diagram.
🎯 Learn the Updated 5-Day Crash Course
If this resonated, the new version of my free 5-Day Crash Course – From Developer to Architect will take you deeper into:
Mindset Shift - From task finisher to system shaper
Design for Change - Build for today, adapt for tomorrow
Tradeoff Thinking - Decide with context, not dogma
Architecture = Communication - Align minds, not just modules
Lead Without the Title - Influence decisions before you’re promoted
It’s 5 short, focused lessons designed for busy engineers, and it’s free.
👋 Wrapping Up
The first diagram is always wrong.
That’s not failure, that’s the point.
Architects:
Treat diagrams as hypotheses
Invite feedback early
Expect reality to rewrite the plan
Capture lessons for the next design
The goal isn’t to defend the first diagram.
It’s to evolve it until it tells the truth.
Thanks for reading.
See you next week,
Bogdan Colța
Tech Architect Insights