How to Crack a Salesforce Developer Interview: A 30-Day Plan

To crack a Salesforce developer interview in 30 days, split the month into four focused weeks. Week one covers Apex, SOQL and triggers. Week two covers async Apex, testing and integration. Week three covers Lightning Web Components and Flows. Week four is for project stories, mock interviews and live-coding practice. Each weekday gets one disciplined 90-minute block, and weekends go to longer builds and mocks. This plan assumes you've already written some Apex. It sharpens what you know and shows you how to explain it under pressure.

I'll be direct about one thing first. No plan, course or book can promise you an offer. What a plan can do is remove the two most common reasons good developers fail: shallow answers to follow-up questions, and freezing when they're asked to write code in front of someone.

Who this plan is for

This plan is for you if you've built at least a trigger, a test class and a simple component, and you have an interview coming up in the next month or two. That could be a first developer role after admin work, or a move to a mid-level role.

If you've never written Apex, 30 days of interview prep is the wrong tool. Follow the Salesforce developer roadmap first, then come back to this plan.

How Salesforce developer interviews usually run

Every company runs its process differently, but most combine some of these:

• A screening round. Quick concept questions to check you're not bluffing.
• One or two technical rounds. These are scenario questions, such as "a trigger on Opportunity is failing during a data load, walk me through it". The follow-ups are where the real assessment happens.
• Live coding or a take-home. Usually a trigger, a test class, a small LWC or a SOQL problem.
• A project discussion. You explain something you built, and they probe your decisions.
• A manager or culture round.

The plan below prepares you for all five. The scenario follow-ups are the part most people underprepare for.

The daily 90-minute block

Consistency beats intensity here. On each weekday, do one block in this order:

On weekends, spend two or three hours on a larger build and record one mock-interview answer on video.

Week 1: Apex, SOQL and triggers

This week is about the foundations every Salesforce interviewer checks first.

Drill: Apex interview questions, SOQL interview questions and Apex trigger interview questions.

Topics, roughly one per day:

1. Governor limits, and why Salesforce has them at all (multitenancy).
2. Bulkification: collecting IDs, querying once, using maps, and DML on lists.
3. Trigger context variables, before vs after triggers, and when to use each.
4. A trigger handler pattern and recursion control.
5. SOQL: relationship queries, aggregate queries, selective filters and why query selectivity matters on large objects.

Build by Sunday: a bulkified trigger with a handler class and a test class that inserts 200 records and uses the Assert class. If you can't explain why the test uses 200 records, read Apex bulkification explained.

Follow-ups to rehearse: "What happens if this runs on 10,000 records from Data Loader?" "Where would this fail if the user doesn't have access to the field?" "Why not do this in a Flow?"

Week 2: Async Apex, testing and integration

Mid-level interviews separate candidates here.

Drill: async Apex interview questions and Salesforce integration interview questions.

Topics:

1. Future methods vs Queueable vs Batch vs Schedulable. Know when you'd pick each and what each one can't do.
2. Why you can't make a synchronous callout straight from a trigger, and the usual way around it.
3. Mixed DML errors, and how to separate setup and non-setup object operations.
4. Testing: Test.startTest() and Test.stopTest() for async code, System.runAs for user context, and HttpCalloutMock for callouts.
5. Integration basics: Named Credentials and External Credentials, REST from Apex, and when to choose Platform Events over a direct callout.

Build by Sunday: a Queueable that makes a callout through a Named Credential, plus a test that mocks the response and asserts on the result.

Week 3: Lightning Web Components and Flows

Drill: LWC interview questions and Salesforce Flow interview questions.

Topics:

1. Component communication: properties down, events up, and Lightning Message Service across the DOM.
2. @wire vs imperative Apex calls, and when you'd choose each.
3. Lightning Data Service and why it often beats a custom Apex method.
4. Reactivity: why reassigning an array re-renders and mutating it in place doesn't.
5. Flow vs Apex: before-save record-triggered flows, after-save flows, and how Flows and triggers share the order of execution.

Build by Sunday: an LWC that lists related records using @wire with a reactive parameter, a child component that fires a custom event, and no expressions in the template. Compute everything in getters. Some interviewers will ask why. The answer is that LWC templates are designed to bind properties and getters rather than arbitrary JavaScript, which keeps logic in the class where you can read and test it.

Week 4: Projects, mock interviews and live coding

Start the week by reading your mistake log from weeks one to three. Your weakest topics get the first three days' recall blocks.

Then spend the rest of the week on three things: your project stories, mock interviews and timed coding.

Explaining your projects: STAR, adapted for Salesforce

Generic STAR (Situation, Task, Action, Result) works, but Salesforce interviewers listen for specific things. Here's how I'd adapt each letter.

Situation: the org, not just the business. Say which objects were involved, the rough data volumes, the users and any integrations. "A service org with a few million cases, a partner community and an ERP integration" tells the interviewer what constraints you were working under.

Task: the requirement and its constraints. Governor limits, sharing rules, deadlines, existing automation you couldn't touch. Constraints are what make a decision interesting.

Action: decisions, and the alternatives you rejected. This is where most candidates undersell themselves. Don't just say "I wrote a batch class". Say: "I considered a record-triggered Flow, but the logic needed a callout and had to handle large data loads, so I used a trigger that enqueued a Queueable, and I kept the handler bulk-safe."

Result: what changed, and what you'd do differently. Use real numbers only if they're real. Otherwise describe the observable outcome, such as "the nightly load stopped failing". End with one thing you'd change. That single sentence shows more seniority than anything else in the answer.

If your experience is mostly training projects, that's fine. Say so plainly. Then explain your project with the same rigour. A well-reasoned training build beats an exaggerated "real" project that falls apart at the second follow-up.

Mock interview tactics that actually help

• Ask for follow-up chains, not single questions. Have a friend or colleague ask "why?" and "what if?" at least three times after each answer. That's how real technical rounds work.
• Record yourself. Watch for filler, for answers that run past two minutes, and for the word "basically" covering a gap.
• Randomise. Pull questions at random from across all four weeks. Real interviews don't announce the topic.
• Practise saying "I don't know, but here's how I'd find out." Then name the actual method: a debug log, the developer guide, a quick test in a scratch org. Interviewers respect that far more than a confident guess.

Live coding and take-home strategy

For live coding, follow the same five steps every time:

1. Clarify. Ask which object, which events (insert, update, delete), whether records can be reparented, and whether nulls are possible.
2. State your assumptions out loud. "I'll assume bulk loads of up to 200 records per trigger chunk, sharing should be enforced, and the field can be empty."
3. Write the skeleton first. Collect IDs, run one query, build a map, loop, then do one DML on a list. Even unfinished, a correct skeleton shows you think in bulk.
4. Narrate. Silence reads as being stuck. Explain each choice as you type.
5. Test. Say how you'd test it: a test class with 200 records, a negative case and a different user context.

For a take-home, treat it as a small production change. Include a short README covering assumptions and trade-offs, a test class that uses the Assert class with bulk and negative cases, with sharing on your classes, user-mode queries where they make sense, and a clean commit history. Don't over-engineer. A tidy trigger handler beats an enterprise framework nobody asked for.

Where Salesforce Casts fits in

The Interview Questions course covers Apex development, Apex triggers, Lightning Web Components and Aura, and it's included in every plan. The Lifetime plan also includes the Interview Questions Book, 700+ pages, which is the reference I'd keep open during the daily recall blocks.

For the build blocks, the main courses line up with the weeks. Use Salesforce Development (Visualforce & Apex) for week one, Apex Test Fest and Salesforce Integration Master Course (Advanced Apex) for week two, and Lightning Web Components Development for week three.

To be clear about the limits: there are no mock interviews, scheduled classes or 1:1 mentoring. Questions go to the discussion group. Mock interviews need a human, so find a peer, colleague or study partner for those.

What this plan can't do for you

It can't give you experience you don't have, and it can't promise an offer. Interviews involve luck, timing and fit as well as skill.

What it can do is make sure that when you're asked "why?", you have an answer you've actually built, broken and fixed yourself. That's usually the difference between a candidate who sounds trained and one who sounds like a developer.