Think Like an Architect: The Field Guide to Cloud Egress and Data Gravity

When you’re designing for Day 2 operations, you quickly realize that data isn’t just heavy—it’s expensive to move. I’ve seen countless “cloud-native” projects hit a wall during the scaling phase because the architect assumed egress was a flat overhead. It isn’t. It’s a variable tax that scales with your success.

To build like an engineer, you need to understand the nuances of how the “Big Three” handle the exit of every byte. Here is the deep-dive technical breakdown of the egress philosophies for AWS, GCP, and Azure.

The Deep Dive: Provider Egress Philosophies

1. AWS: The Volume-Heavy Waterfall

AWS S3 egress pricing is the industry benchmark. Their model is built on the “more you move, the less you pay” principle, but the tiers are wide.

• Technical Nuance: AWS recently increased the “Free Tier” to 100 GB/month for internet egress. For an enterprise architect, this is a rounding error, but it’s a vital “free trial” for PoCs.
• The “Squeeze” Tier: The 100GB to 10TB range is the most expensive ($0.09/GB). Most mid-market architectures live here and suffer the highest margins.
• Architect’s Tip: If you are nearing 150TB, you must push for the $0.05/GB tier. This is where “Cloud Adjacent” storage (like Equinix or Pure Storage) starts to become more cost-effective than native S3.

2. GCP: The Network Service Tier Strategy

Google Cloud doesn’t just look at volume; they look at routing paths. This is a frequent “gotcha” for architects moving from AWS.

• Standard vs. Premium: Our Egress Calculator models the Standard Tier (routing over the public internet). However, GCP often defaults to the Premium Tier (routing over Google’s private global backbone), which can add a significant premium.
• The Flat-Tier Trap: GCP’s egress usually starts higher ($0.12/GB for the first 10TB) and doesn’t drop as aggressively as AWS.
• The Decision: Choose GCP if your data needs to reach global users with the lowest latency (Premium Tier), but avoid it for bulk, non-time-sensitive migrations unless you’re using the Standard Tier.

3. Azure: The “Zone & Global Network” Model

Azure is the “wild card.” Their pricing is competitive on the surface but contains complex geographical dependencies.

• The Routing Preference: Like GCP, Azure offers “Routing Preference.” Choosing ISP Routing (Cold Potato) is cheaper as it offloads traffic to the internet immediately. Microsoft Global Network (Hot Potato) keeps it on their fiber longer for a fee.
• The Inter-AZ “Zone Tax“: Azure is particularly aggressive with billing for data moving between Availability Zones in the same region. At $0.01/GB, high-availability clusters that sync data constantly can generate “phantom” egress bills that rival internet egress.
• Integration Advantage: Azure often waives or reduces egress for customers moving data into Azure from other clouds during a migration phase—a leverage point every SE should use during negotiations.

The Decision Framework: Side-by-Side Comparison

Estimated Monthly Internet Egress (US-East Regions)

Key Takeaways

• The $0.09 Benchmark is Dead: While often cited as the “standard” rate, actual costs vary by up to 40% depending on routing preferences and volume tiers.
• Azure is the “Zone Tax” King: Azure often has lower internet egress rates but compensates with aggressive “Inter-AZ” (Availability Zone) billing that can catch SEs off guard.
• GCP Charges for Quality: Google is the only provider that explicitly lets you choose between a “Standard” (Public Internet) and “Premium” (Google Fiber) routing path, with costs to match.
• Volume is Your Only Leverage: All three providers use a “waterfall” model; if you aren’t hitting the 50TB+ tiers, you are paying the maximum retail margin

Conclusion: Egress is an Architectural Choice

Egress is not just a line item on a cloud bill; it’s a fundamental architectural constraint. As Solutions Engineers and Cloud Architects, our job isn’t just to build; it’s to build sustainably. Understanding the nuanced, tiered pricing models of AWS, GCP, and Azure is critical to preventing budget overruns and designing truly optimized multi-cloud or hybrid solutions. Use tools like the Rack2Cloud Egress Calculator to quantify these costs upfront, empowering you to make informed decisions and build with confidence.

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About The Architect

R.M.

Senior Solutions Architect with 25+ years of experience in HCI, cloud strategy, and data resilience. As the lead behind Rack2Cloud, I focus on lab-verified guidance for complex enterprise transitions. View Credentials →