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ADR-006: AWS us-east-1 Primary Region

Status: Accepted Date: February 2026

Context​

Cloud infrastructure placement affects latency, compliance, cost, and available services. The original Blueprint assumed EU-first deployment (Frankfurt or Ireland). The US-first correction requires re-evaluating the primary region.

Decision​

Deploy primary infrastructure in AWS us-east-1 (N. Virginia), with EU region (eu-west-1 Ireland) added at Global Expansion stage.

Alternatives Considered​

Alternative 1: AWS eu-west-1 (Ireland) Primary​

  • Pro: EU data residency from day one, aligns with "EU-grade" philosophy
  • Con: Higher latency for US users, McKinsey is US-based, some AWS services launch in us-east-1 first
  • Rejected because: US-first strategy means US region primary

Alternative 2: AWS us-west-2 (Oregon)​

  • Pro: Lower cost for some services, good West Coast latency
  • Con: Higher latency for East Coast US (where McKinsey HQ is), fewer financial/enterprise compliance certifications
  • Rejected because: McKinsey and most Fortune 500 HQs are East Coast

Alternative 3: GCP or Azure​

  • Pro: GCP has strong AI/ML services; Azure has enterprise integration (Active Directory)
  • Con: AWS has broadest compliance certifications (FedRAMP, HIPAA, SOC), most enterprise familiarity, largest partner ecosystem
  • Rejected because: AWS is the safest choice for enterprise compliance across all future regulatory regimes

Alternative 4: Multi-Cloud from Day 1​

  • Pro: No vendor lock-in, maximum resilience
  • Con: Enormous engineering overhead, inconsistent security controls, double the compliance work
  • Rejected because: Startup can't sustain multi-cloud operations. Lock-in risk is acceptable.

Consequences​

Positive​

  • Lowest latency for primary US market
  • Broadest AWS service availability
  • Most compliance certifications available
  • Best pricing for most services
  • Easy expansion to eu-west-1 when needed (Terraform parameterized by region)

Negative​

  • EU data residency requires separate deployment when EU clients arrive
  • Some latency for India-based engineering team (acceptable for development work)
  • LLM API calls to Anthropic are likely routed through US anyway

Multi-Region Expansion Plan​

StageRegionPurpose
MVP0-GAus-east-1Primary (all clients)
Globaleu-west-1EU client data residency
Global+ap-southeast-1APAC (if needed)

References​