book

Crafting Engineering Strategy

by Will Larson

October 2025

Intermediate to advanced

310 pages

7h 6m

English

O'Reilly Media, Inc.

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What This Book Is NotNavigating This BookUsing Code ExamplesO’Reilly Online LearningHow to Contact UsAcknowledgments
Grounded in My Direct ExperienceAdapting Rumelt for EngineeringIterative, Intellectual, and MechanicalThis Book’s Ambition
There’s Always a StrategyStrategy Changes CompaniesInappropriate Strategy Is Especially ImpactfulWritten Strategy Drives Organizational LearningImplicit Strategy Comes at a CostWriting Strategy Supports Personal LearningSummary
Doing Strategy as an EngineerDoing Strategy as an ExecutiveDoing Strategy in Other RolesDoing Strategy in Challenging EnvironmentsLow-Trust EnvironmentPoor-Judgment EnvironmentDealing with Missing StrategiesWho Shouldn’t Do Strategy?Summary
When to Write StrategyCurrent Strategic StateTrends in Strategic StateYour Context LevelHow Much Strategy to WriteStrategy AltitudeAre You Doing Too Much?Summary
How the Steps Become StrategyStep 1: ExploringStep 2: DiagnosingStep 3: RefiningStep 4: Setting PolicyStep 5: OperationsIs the Structure Sacrosanct?Summary
What Is Exploration?When to ExploreHow to ExploreMine Your Organization for Internal PrecedentUsing Your NetworkRead Widely; Read NarrowlyEach Job Is an EducationSave Judgment for LaterSummary
Diagnosis Is Strategy’s FoundationHow to Develop Your DiagnosisIncorporating Data into Your DiagnosisWhisper the Controversial PartsReframe Blockers as Part of Your DiagnosisThe Role of Self-AwarenessSummary

What Is Strategy Refinement?Does Refinement Matter?If It Matters, Why Is It Skipped?Building Your ToolkitStrategy TestingSystems ModelingWardley MappingAntipatterns in RefinementSummary
What Is Policy?How to Set PolicyHow Many Policies?Kinds of PoliciesApprovalsAllocationsDirectionGuidanceMaintaining Strategy AltitudeCriteria for Effective PoliciesDeveloping Novel PoliciesAre Competing Policy Proposals an Antipattern?Recognizing ConstraintsDealing with Missing StrategiesSummary
What Are Operational Mechanisms?How to Evaluate Mechanisms: A RubricComposing an Operational PlanEffective Mechanisms and PatternsApproval and Advice ForumsInspectionNudgesDocumentation and TrainingAutomationDeferral to Future WorkMeetingsAntipatterns and Ineffective MechanismsWhat If You’re Not an Executive?Beware Cargo-CultingSummary
Why Writing Structure Inhibits ReadingToo Long, Didn’t ReadApproval Meeting to NowhereTransient AlignmentInverting the Document Structure for ReadingStrategy RefactoringAdditional Tips for Writing Effective Strategy DocumentsSummary
Clear, Definitive DocumentsDoing Strategy Despite Unrealistic TimelinesUsing Strategy as a NonexecutiveDoing Strategy in Chaotic EnvironmentsUnreliable InformationSurviving Other People’s Bad Strategy WorkSummary
When to Test StrategyHow to Test StrategyTesting Roles: Sponsors and GuidesMeetings and MetricsIdentifying Untested StrategiesRecovering from Skipped TestingSummary
A Two-Minute PrimerWhen Is Systems Modeling Useful?ToolingHow to ModelDeeper ExplorationHow to Document a ModelWhat Systems Modeling Isn’tSummary
Wardley Mapping: A 10-Minute PrimerComponents of a Wardley MapX-axisY-axisTools for Wardley MappingWhen Are Wardley Maps Useful?How to Wardley MapBreadcrumbs for Wardley Map ExamplesHow to Document a Wardley MapWhat About Doctrines and Gameplay?Summary
Reading These DocumentsDocument 16-1: Service Migration Strategy: UberPolicy and OperationRefineDiagnoseExploreDocument 16-2: Service Onboarding ModelLearningsSketchReasonModelExerciseDocument 16-3: Wardley Mapping the Service Orchestration EcosystemHow Things Work TodayTransition to Future StateUser and Value ChainsSummary
Reading These DocumentsDocument 17-1: How Should We Adopt Large Language Models?PolicyDiagnoseExploreDocument 17-2: Modeling LLMs’ Impact on the Developer ExperienceLearningsSketchReasonModelExerciseDocument 17-3: Wardley Mapping the LLM EcosystemHow Things Work TodayTransition to Future StateUser and Value ChainsDocument 17-4: Modeling Driver OnboardingLearningsSketchReasonModelExerciseSummary
Reading These DocumentsDocument 18-1: Navigating Private Equity OwnershipPolicyDiagnoseExploreDocument 18-2: Engineering Organization Seniority-Mix ModelLearningsSketchReasonModel and ExerciseSummary
Reading This DocumentDocument 19-1: How Should We Control Access to User Data?Policy and OperationsDiagnoseExploreSummary
Reading This DocumentDocument 20-1: Should We Decompose Our Monolith?PolicyDiagnoseExploreSummary
Reading These DocumentsDocument 21-1: “We’re a Product Engineering Company!”: Engineering Strategy at CalmPolicy and OperationDiagnoseExploreDocument 21-2: How to Resource Engineering-Driven Projects at CalmPolicy and OperationDiagnosisExploreSummary
Reading These DocumentsDocument 22-1: How Should Stripe Deprecate APIs?Policy and OperationDiagnosisDocument 22-2: A Systems Model of API DeprecationLearningsSketchReasonModelExerciseDocument 22-3: Why Did Stripe Build Sorbet?Policy and OperationDiagnoseDocument 22-4: How to Integrate Stripe’s Acquisition of Index?Policy and OperationDiagnoseExploreSummary
How Are Strategies Evaluated Across the Industry?A Rubric for Evaluating StrategyDoes Stopping a Strategy Mean It’s a Bad Strategy?The Unpierceable VeilLearning from Failed StrategiesSummary
Exploring Strategy CreationPublic ResourcesPrivate ResourcesWorking in CommunityDiagnosing Your Prior and Current Strategy WorkPolicy for Improving at StrategyWhat If You’re Not Allowed to Do Strategy?Operating Your Strategy Improvement PoliciesToo Busy for StrategyFinal Words
My Prior WritingBooksCase Studies

Content preview from Crafting Engineering Strategy

Chapter 20. Service Architecture Strategy

Since the first introduction of microservices in 2005, the debate between adopting a microservices architecture, a monolithic service architecture, or a hybrid between the two has become one of the least reversible decisions that most engineering organizations make. Even migrating to a different database technology is generally a less expensive change than moving from monolith to microservices or from microservices to monolith.

The industry has in many ways gone full circle on that debate. While most hyperscalers in the 2010s took part in multiyear monolith-to-microservices migrations, Kelsey Hightower’s iconic 2017 tweet predicted that “Monolithic applications will be back in style after people discover the drawbacks of distributed monolithic applications.”

Even as popular sentiment has generally turned away from microservices, many engineering organizations have a bit of both, often the remnants of one or more earlier but incomplete migration efforts. This service architecture strategy looks at a fictional organization stuck with a bit of both approaches and looking to determine its path forward. Let’s call it Theoretical Compliance Company.

Reading This Document

This chapter contains just one document, Document 20-1: Should We Decompose Our Monolith?, written in 2022.

If you’re reading this document with the goal of applying the strategies it puts forward, start at the top and read to the end. If, on the other hand, your main goal ...