Self-assessment checklist

A gap check for the skills a new developer is expected to have. Read each item and tick it only if you can do it without help or looking it up. If you cannot, follow the related topics under the item and come back later.

Done: 0 of 78 items

Hide completed items

Working Environment0/6

Navigate, create, copy, move, and delete files and folders from the terminal, in cmd, PowerShell, and Bash. You should be able to do this without a file explorer, including for paths that contain spaces.Related: Command Line Basics
Chain commands with a pipe and redirect output to a file in each shell. For example, filter a long command output down to the lines you need and save the result.Related: Command Line Basics
Explain absolute vs relative paths. Be able to say which kind of path a script depends on and why it might break on another machine.Related: Command Line Basics, Windows vs Linux Differences
Set an environment variable for the current session and permanently, and read it from a program. Keep local settings and secrets in a .env file that stays out of Git.Related: Environment Variables
Describe the main differences between Windows and Linux (paths, case sensitivity, line endings, permissions). Know which of them cause a script that works on your machine to fail on a server.Related: Windows vs Linux Differences
List running processes and stop one on both operating systems. Use this to find a program that is holding a port or has stopped responding.Related: Command Line Basics, Windows for Developers, Linux for Developers, Networking Basics

Programming Concepts0/7

Choose between a list, map, and set for a given problem. Say what you need from the data, such as order, lookup by key or no duplicates, and why that points to one of them. Replace a repeated search in a list with a set or map.Related: Data Structures
Handle an error so the program fails predictably with a useful message. The message should say what went wrong and what the caller can do, and should not expose internal details to users.Related: Error Handling
Improve the readability of a small piece of code through naming and structure. Rename unclear variables and split a long function, then check that the behaviour is unchanged.Related: Clean Code and Naming, Refactoring Basics
Refactor a function in small steps with tests. Run the tests after every step, and keep refactoring commits separate from commits that change behaviour.Related: Refactoring Basics, Unit Testing
Convert structured data to JSON and back. Know what is lost or changed on the way, such as dates, missing values and extra fields.Related: Data Serialization, JSON Fundamentals
Explain why storing timestamps in UTC is a good default. Describe a bug that appears when two users in different time zones, or a daylight saving change, are involved.Related: Dates, Times, and Time Zones
List the state in a small feature. For each piece, say where it lives, who can change it, and whether the same fact is stored in two places.Related: State Management

Software Development Process0/9

Trace a released change from the requirement to production. Find its ticket, pull request, pipeline run and the deployed version, and say who was involved at each stage and where it could have been sent back.Related: Software Development Lifecycle (SDLC), Requirements and User Stories, CI/CD Basics
Rewrite a ticket as a user story with acceptance criteria. Write the criteria as Given, When, Then, and list the questions you would ask before starting.Related: Requirements and User Stories
Find where a feature is implemented in an unfamiliar codebase. Use search, the folder structure and the debugger to trace from what a user sees to the code that produces it.Related: Navigating Large Codebases, Reading Existing Code
Reproduce a bug and reduce it to a minimal case. Write down the steps and input that trigger it, using the same version and environment as the report, ideally as a failing test or script.Related: Reproducing Bugs
Find the cause of a bug with the debugger. Set a breakpoint, step through, read the call stack, find where the first wrong value appears, state the root cause and add a test that fails without the fix.Related: Debugging Fundamentals, Root Cause Analysis
Break a large task into small steps that can each be verified. After every step the code should still build and you should be able to tell whether it works.Related: Incremental Problem Solving
Explain the difference between build, run, and deploy. Say where each happens and which problems show up in which step.Related: Build vs Run vs Deploy, CI/CD Basics
Explain why dev, test, and production environments exist and how they differ. Give an example of a change that should be tried in test before it reaches production.Related: Environments (Dev, Test, Staging, Production)
Describe what a CI pipeline does when a commit is pushed. List the usual steps, such as build, tests and checks, and say what you would do when one of them fails.Related: CI/CD Basics

Testing Fundamentals0/5

Write and run a simple unit test. It should have a clear name, one thing to check, and fail when the code under test is broken.Related: Unit Testing
Explain the difference between a unit test and an integration test. Give an example of a problem that only the integration test would catch.Related: Unit Testing, Integration Testing
Write a bug report that someone else can reproduce. Include the steps, expected and actual results, and the version or environment you used.Related: Defect Reporting, Reproducing Bugs
Test a feature beyond the happy path. Try a value at each side of a limit, an unusual input and an action out of order, and write down what you found.Related: Manual Testing Techniques
Give each test the data it needs so the tests pass in any order. Explain why real production data must not be copied into a test environment.Related: Test Data Management

Databases and Data0/4

Write a query with filtering, sorting, and a join. Use it to answer a question that needs data from two tables, such as orders with the name of the customer.Related: SQL Fundamentals, Relational Database Concepts
Read a table schema and point out the primary key, the foreign keys and an index. Say what each one does for the data and for the speed of queries, and which column should get an index.Related: Relational Database Concepts, Indexing Basics
Sketch the tables, keys and relationships for a small domain, such as books, members and loans. Say where each foreign key goes and name one rule a constraint should enforce.Related: Data Modeling
Show that a rolled-back change leaves the data untouched. Explain why two related updates, such as a money transfer, belong in one transaction.Related: Transactions

Networking, Web, and APIs0/6

Explain what DNS, an IP address, and a port are. Describe how they work together when you open a site or start a local server.Related: Networking Basics
Call an API and interpret the status code, headers, and JSON body. Use a tool such as curl or Postman, and say whether the call worked and how you know.Related: HTTP Fundamentals, JSON Fundamentals, API Testing Tools
Explain the difference between 401, 403, 404, and 500. For each one, say whether the fault is likely with the caller or the server and what you would check first.Related: HTTP Fundamentals
Describe what HTTPS adds when a client calls an API. Explain what the certificate and the encrypted connection protect, and recognise a certificate error such as an expired or mismatched certificate.Related: TLS and HTTPS Basics, HTTP Fundamentals, Networking Basics
Work out whether a failed connection is a name lookup problem, a closed port or a firewall. Use commands such as dig or Resolve-DnsName and nc or Test-NetConnection, and read what each result tells you.Related: Networking Basics
Fix an invalid JSON payload by hand. Spot a trailing comma, single quotes or a missing bracket, and say what each parse error means.Related: JSON Fundamentals

Security Awareness for Developers0/8

Explain why credentials must never be committed to source control. Describe what can happen when they are, and why deleting them in a later commit does not fix it.Related: Secrets Management, Ignoring and Excluding Files
Explain authentication vs authorization. Give an example where a user passes the first and still gets refused by the second.Related: Authentication vs Authorization
Explain why input must be validated on the server even when the browser already checks it. Describe what an attacker can do by skipping the checks in the browser.Related: Input Validation
Validate a field on the server. Check type, length and range against an allowlist, and return a clear 400 error without echoing the input back.Related: Input Validation
Explain why passwords are hashed rather than stored or encrypted. Say what an attacker gets from a leaked database in each case.Related: Password Security
Describe how SQL injection works and how to prevent it. Show the difference between building a query from strings and using parameters.Related: Common Vulnerabilities, Input Validation, SQL Fundamentals
Run your ecosystem's dependency audit, such as npm audit. Read one finding and say which package is affected, whether it is a direct dependency, and how it would be fixed.Related: Dependency Risks
Look at a small feature such as login or file upload and say how it could be abused. Name one design rule, such as least privilege, that limits the damage.Related: Secure Development Mindset

Logging, Monitoring, and Troubleshooting0/6

Add a log statement at an appropriate level that will be useful in production. It should say what happened and include the identifiers needed to find the case, without logging passwords or personal data.Related: Logging Fundamentals
Find the relevant entries in a log file and follow a request through them. Filter by a correlation id or timestamps, show the lines around a match, and watch a live log while you reproduce the problem.Related: Log Analysis
Trace one value from the browser through the API and into the database. Check each layer in turn and name the first one where the value is wrong.Related: Following a Change Through a System
Investigate a failure using logs and configuration before asking for help. Keep a short log of symptom, evidence, hypothesis, test and result, so that you can say what you checked and found.Related: Troubleshooting Methodology, Log Analysis
Explain the difference between a symptom and a root cause. Take a failure you have seen and name both, and say how you could confirm the cause.Related: Root Cause Analysis, Troubleshooting Methodology
Say how to raise an incident in your team and what you should and should not do during one. Know where the runbook and on-call contact are.Related: Incident Basics

Architecture Fundamentals0/5

Explain separation of concerns using an example. Show how mixing two responsibilities in one place makes a change harder.Related: Separation of Concerns
Describe the layers of an application and what each is responsible for. Say where validation, business rules and database access belong, and why.Related: Layered Architecture
Describe what a module is responsible for in one sentence. Point out a sign of low cohesion or tight coupling, and say how you would reduce it.Related: Modularity, Coupling, and Cohesion
Describe the difference between a VM and a container. Say what each one isolates, how heavy it is, and when you would choose it.Related: Servers, VMs, and Containers
Explain what to do when a call to another service times out. Describe a retry with a limit and a delay, and why a retried payment must not be charged twice.Related: Distributed Systems Basics

Collaboration and Professional Practice0/8

Explain a user story, its acceptance criteria, and the team's Definition of Done. Use a story from your own team to show how the three differ.Related: Requirements and User Stories, Agile, Scrum, and Kanban, Ownership and Time Management
Ask a question that includes context, evidence, and what has been tried. Someone should be able to answer it without coming back to you with follow-up questions.Related: Asking Good Questions
Explain a technical topic to a non-technical colleague in a few sentences. Avoid jargon and use a familiar analogy or an example from their own work.Related: Effective Technical Communication
Write a short status update about a problem. Lead with the conclusion and what you need, and keep what is confirmed apart from what you only suspect.Related: Effective Technical Communication
Raise a risk early. State the facts, the impact, your options and when you will give the next update.Related: Ownership and Time Management
Write a README that lets a colleague set up and run a project. Test it by following the steps yourself on a clean machine, or have someone else try.Related: Documentation Skills, Repository Structure
Write up something you learned in five to ten lines with one example. Put it where the team will find it again.Related: Knowledge Sharing, Documentation Skills
Explain ten glossary terms in your own words. Pick terms you have heard but never had to define, and check your explanation against the glossary.Related: Common Development Terminology

AI-Assisted Development0/4

Explain what information must not be pasted into an AI tool. Cover secrets, customer data and confidential code, and say where to look up your organisation's rules.Related: Confidentiality and AI, Secrets Management
Reduce what you share before asking an AI tool for help. Cut the smallest snippet, replace names and values, and say what to do after a mistaken paste.Related: Confidentiality and AI
Verify a generated code snippet with tests before using it. Check that the packages and functions it uses exist, that it handles the edge cases and fails when it should, and do not rely on it looking correct.Related: Verifying AI Output, Unit Testing
Write a prompt with context, constraints and the form of answer you want, and follow up on a wrong answer. Do not commit code you cannot explain.Related: Using AI Assistants Effectively