← Glossary
Common core + local layers
Common core + local layers is how you scale across markets, channels, and partners without creating a Frankenstein product. You design what must stay consistent—and you explicitly design what can vary.
Definition
- The common core is the shared foundation: system primitives, patterns, language, and key flows that must remain coherent.
- Local layers are controlled variations: market rules, regulatory constraints, content, payment rails, operational realities.
- The model only works when “local” is designed, not improvised.
- This is not just architecture; it’s a governance contract: what teams can change, how they change it, and how divergence is controlled.
Why it matters
- Global programs fail when teams either over-standardise (ignoring local reality) or over-localise (fragmenting the product).
- Ecosystems amplify divergence: vendors, APIs, and regulations change per market.
- A clear core/local model accelerates delivery: teams reuse what works and adapt with guardrails.
- In practice, this is where many digital programs fail: the concept is understood, but the operating discipline is missing.
Common failure modes
- False universality: assuming a single flow can satisfy all markets.
- Local exceptions with no rules: every market becomes a bespoke fork.
- Design system without governance: components are shared, but meaning and behavior diverge.
- No versioning: changes to core break local implementations unpredictably.
- “Local” as politics: stakeholders demand customisation without cost accountability.
How I design it
- Define core primitives: identity, payments, state models, error handling, auditability patterns.
- Define the variation surface: what can change (copy, content, compliance steps, integrations) and how.
- Create pattern evolution rules: required vs optional patterns, exception process, deprecation.
- Use state models to manage differences: states stay consistent even if steps vary per market.
- Measure fragmentation: exception rate, divergent pattern variants, support debt by market.
- Represent core vs local explicitly in artifacts: maps, patterns, and naming conventions that prevent accidental forks.
- Treat it as a repeatable pattern: define it, test it in production, measure it, and evolve it with evidence.
Related work
Proof map claims
Case studies
See also
Contact
Let’s discuss a leadership role, advisory work, or a complex product challenge.