Salesforce LWC Interview Questions 2026 — Complete Guide (120 Questions) | SF Interview Pro

⚡ Complete LWC Series 2026

Salesforce LWC Interview Questions — Complete Guide 2026

120 questions across 3 parts — from basic decorators to advanced architecture. Everything you need to crack any LWC interview in 2026.

120Questions

3Parts

🟢🟠🔴All Levels

100%Free

Start Part 1 → ← All Topics

Part 1 · Q1–Q40

LWC Fundamentals & Core Concepts

LWC vs Aura, Decorators, Lifecycle Hooks, Wire, Events, LMS, LDS, Navigation & more

Why LWC over Aura?

@api, @track, @wire

All 5 Lifecycle Hooks

Wire vs Imperative Apex

Parent ↔ Child Communication

Lightning Message Service

Lightning Data Service (LDS)

NavigationMixin

Toast Notifications

refreshApex()

cacheable=true

Pagination (20K records)

Part 2 · Q41–Q80

Advanced LWC — Slots, Datatable & Integration

Shadow DOM, Dynamic Components, Record Forms, Datatable, Platform Events, Jest & Performance

Slots — Default & Named

Shadow DOM Deep Dive

lwc:if vs if:true

Dynamic Components

lightning-datatable

Inline Editing + Apex Save

Platform Events (EmpApi)

Static Resources

Custom Modal

LWC Jest Testing

CSS Custom Properties

Performance Optimization

Part 3 · Q81–Q120

Expert LWC — Architecture & Real Builds

Accessibility, CDC, Kanban, Virtual Scroll, Agentforce, Anti-Patterns & Senior Interview Topics

Accessibility & ARIA

Lightning Locker & LWS

Change Data Capture

Lightning Flow in LWC

Kanban with Drag & Drop

Star Rating Component

Virtual Scroll

Reactive Properties Deep Dive

Service Component Pattern

Optimistic UI Updates

Agentforce LWC Actions

LWC Anti-Patterns

📋 Complete Topic Index — All 120 Questions

Q#	Topic	Level	Part
Q1	Why LWC over Aura? What is faster?	Basic	Part 1
Q2–Q3	HTML File & JavaScript File in LWC Bundle	Basic	Part 1
Q4–Q5	Types of Decorators — @api, @track, @wire explained	Intermediate	Part 1
Q6–Q9	Wire — How many times, connectedCallback vs Wire, inside connectedCallback	Intermediate	Part 1
Q8	All 5 LWC Lifecycle Hooks with differences	Intermediate	Part 1
Q10	Lightning Message Service (LMS)	Advanced	Part 1
Q12	Toast Notifications — ShowToastEvent	Basic	Part 1
Q14–Q15	Parent → Child & Child → Parent Communication	Intermediate	Part 1
Q20	cacheable=true — what it means, limitations	Advanced	Part 1
Q23–Q25	Ways to call Apex — Wire vs Imperative deep dive	Intermediate	Part 1
Q28–Q30	Lightning Data Service — getRecord, createRecord, updateRecord	Advanced	Part 1
Q38	refreshApex() — when and how to use	Intermediate	Part 1
Q39–Q40	Pagination for 20,000 records + Chaining Apex calls	Advanced	Part 1
Q41–Q42	Slots (Default & Named) + Shadow DOM	Intermediate	Part 2
Q43–Q44	lwc:if vs if:true + for:each vs iterator	Intermediate	Part 2
Q45	Dynamic Components — lwc:component + lwc:is	Advanced	Part 2
Q46–Q47	lightning-record-form Family + Custom Validation	Basic	Part 2
Q48–Q49	lightning-datatable + Inline Editing with Apex	Intermediate	Part 2
Q50	Platform Events — EmpApi subscribe/unsubscribe	Advanced	Part 2
Q53–Q54	File Upload + Custom Modal in LWC	Advanced	Part 2
Q57–Q58	Performance Optimization + LWC Jest Testing	Advanced	Part 2
Q62–Q63	Apex Error Handling + DOM Access in LWC	Intermediate	Part 2
Q64	Custom Lookup Component — full build	Advanced	Part 2
Q70–Q71	Dependent Picklist + Picklist Values without Apex	Advanced	Part 2
Q72	Multi-Step Wizard / Stepper	Advanced	Part 2
Q75	Server-side Pagination — SOQL LIMIT/OFFSET	Advanced	Part 2
Q77–Q78	All Communication Patterns + Reusable Search Filter	Advanced	Part 2
Q80	Senior LWC Developer Interview Topics	Advanced	Part 2
Q81	Accessibility & ARIA in LWC — WCAG 2.1	Intermediate	Part 3
Q82	Lightning Locker & Lightning Web Security	Advanced	Part 3
Q83	Change Data Capture (CDC) in LWC	Advanced	Part 3
Q84–Q85	Lightning Flow in LWC + External Libraries	Intermediate	Part 3
Q86–Q90	Real Builds — Star Rating, Kanban, Timeline, Data Grid, Progress Tracker	Advanced	Part 3
Q91–Q92	All Wire Adapters Reference + CurrentPageReference	Intermediate	Part 3
Q93–Q95	Aura to LWC Migration + Common Bugs + Code Review Checklist	Intermediate	Part 3
Q98–Q99	Newest LWC Features 2025-26 + Agentforce Actions	Advanced	Part 3
Q100	Complete Lifecycle Deep Dive — All Phases	Advanced	Part 3
Q113–Q114	Race Conditions + Virtual Scroll for Large Data	Advanced	Part 3
Q115–Q116	Reactive Properties Deep Dive + Service Component Pattern	Advanced	Part 3
Q119–Q120	LWC Anti-Patterns + Certification Mastery Guide	Advanced	Part 3

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