“The move to LWS made our app both safer and faster. We ship features without worrying about fragile workarounds.”
Case Study: Building a Salesforce App on LWS
Engagement Lead: Priyanka Gawalier
Lightning Web Security | LWC | AppExchange Readiness
“LWS let us modernise the UI with today’s JS patterns—while preserving Salesforce’s strict trust boundaries.”
1. Overview & Objectives
A fintech ISV needed to rebuild its legacy Aura/Locker-based managed package into a modern LWC app on Lightning Web Security (LWS). The app blended sensitive client onboarding, risk scoring, and document workflows—and required safe use of modern JS libraries. We were engaged to deliver a secure-by-design UI that passes security review, improves performance, and unlocks faster feature delivery. Objectives: (1) migrate to LWS without breaking behaviour, (2) enable approved third-party libraries safely, (3) harden data access & cross-namespace patterns, (4) institute CI/CD with automated quality & security gates, and (5) optimise for AppExchange scale and org variability.
2. Delivery Approach
We executed a progressive migration with risk-off ramps and measurable milestones:
Assess & Plan: Locker->LWS compatibility scan, 3rd-party library due diligence, CSP design, threat modelling, and test harness baselining.
Refactor & Isolate: Component boundary clean-up, event scoping, Lightning Message Service for safe cross-component comms, and restricted DOM access patterns compliant with LWS.
Harden & Automate: Jest unit tests, WebdriverIO UI tests, ESLint/Prettier, npm audit/OWASP ZAP pipeline, and SFDX org pool automation.
Integrate & Observe: UI API / GraphQL wire adapters, Named Credentials for outbound calls, telemetry for client-side errors and performance.
Certify & Launch: Security Review readiness, documentation, runbooks and roll-out to pilot customers before GA.
Pillars: Security, UX, Libraries, Data Access, CI/CD, Observability.
Why it works: LWS enforces strict isolation between namespaces and reduces the need for brittle workarounds—so the app remains secure as it scales.
3. Solutions Implemented
1) LWC on LWS: Converted Aura to LWC; replaced direct DOM mutations with reactive templates; event scoping via custom events & LMS to prevent cross-namespace leaks.
2) Third-Party Libraries (Safely): Introduced vetted libraries (charts, PDF, input masks) via Static Resources, integrity checks and wrapper components to control invocation and sanitise inputs.
3) CSP & Data Boundaries: Tight Content Security Policy, whitelisted endpoints, Named Credentials and per-profile permission sets; zero inline script policy; HTML sanitisation for user content.
4) API & Caching: UI API/GraphQL wire adapters for read-heavy UIs; client-side memoization and platform cache patterns for high-traffic views.
5) Files & Documents: Secure document viewer with iframed render service, signed URLs, and size/type validation; background async uploads with user feedback.
6) Testing & Tooling: Jest coverage >85%, mutation tests for critical utils, WebdriverIO smoke for 20 top journeys; ESLint rules for LWS; pre-commit hooks.
7) CI/CD: SFDX source tracking, scratch-org pipelines, org-shape testing, and automated security gates (npm audit, OWASP ZAP, PMD, SF scanner).
8) Telemetry & SLOs: Front-end error capture, Web Vitals dashboards, release health reports, and alerting on regressions.
4. Outcomes & Impact
• Security posture: Passed AppExchange security review first attempt; zero cross-namespace policy violations post-launch.
• Performance: Time-to-interactive improved by 28–41% across key pages; median component render time −35%.
• Velocity: Release cadence increased from quarterly to bi-weekly with automated testing and org pipelines.
• Support load: −32% UI defect tickets via stronger linting and error telemetry.
• User satisfaction: CSAT +14 points—cleaner UX, faster pages, and fewer session breakages.
Next step for your business: Run a 4–6 week LWS readiness sprint—map Locker dependencies, vet libraries, set CSP & testing standards—then migrate two flagship user journeys to de-risk scale-up.