Junaid Khalid
Software engineer, founder, and Computer Science tutor
linkedin.com/in/junaidkhalid22I teach Computer Science one to one, online, at GCSE, IGCSE, O-Level, AS and A-Level. I am not a full-time tutor who also writes a bit of code. I am a working software engineer who teaches, and the whole reason this site exists is that the two are not the same job.
I sat these exams in the Cambridge system myself, so I know what the mark schemes reward and where students hand marks back. I also spend my working week inside the topics the specification names, which means when a student asks why a concept exists rather than what it is called, there is an answer waiting rather than a definition.
I have sat the papers I teach, and then studied them again
Every school qualification below is Cambridge International, the same system Cambridge IGCSE, O-Level and 9618 students are in now. Grades are as they appear on the certificates.
Degree
BSc Software Engineering
National University of Sciences and Technology (NUST), Islamabad, School of Electrical Engineering and Computer Science (SEECS). 2016 to 2020.
A Software Engineering degree rather than a general Computer Science one, which is the more useful of the two here: the coursework project at A-Level is a software engineering exercise wearing a Computer Science badge, and it is marked like one.
Cambridge O Level · 2014
Eight subjects, all A*
Computer Studies, Mathematics, Physics, Chemistry, English Language, First Language Urdu, Pakistan Studies, Islamiyat.
O-Level is the qualification Cambridge International sets at the same stage as IGCSE, on the same grade scale. Computer Studies is Cambridge's own name for the subject at this level.
Cambridge International AS Level · June 2015
A regional distinction across five subjects
Awarded the Cambridge Best Across 5 Regional Distinction.
The same sitting the AICE Diploma below was awarded on.
Cambridge International A Level · June 2016
Straight As across five A Levels
The same papers, mark schemes and examiner conventions that students sitting 9618 meet today, taken in a Cambridge International centre.
Cambridge AICE Diploma · June 2015
Distinction, 350 points
The AICE Diploma is awarded on an aggregate across subject groups rather than on one subject, and Computing was one of the six that counted towards it. Alongside it came the Cambridge Best Across 5 Regional Distinction, a regional distinction across five AS-Level subjects.
Awards
- Prime Minister's Laptop Award, 2019.
- NUST Merit Scholarship, 2017 and 2019.
- High Achiever's Award from the Principal of SEECS, the NUST school of electrical engineering and computer science.
- Gold Medalist, 2013 to 2016.
The degree modules that sit under a school Computer Science specification
- CS-220 Database SystemsA
- CS-381 Network SecurityA
- CS-212 Object Oriented ProgrammingA
- CS-344 Web EngineeringA
- EE-353 Computer NetworksB+
- CS-330 Operating SystemsB+
- CS-250 Data Structures & AlgorithmsB+
- CS-251 Design & Analysis of AlgorithmsB+
- EE-321 Computer Architecture and OrganizationB+
- EE-221 Digital Logic DesignB+
- EE-322 Wireless NetworksB+
- MATH-161 Discrete MathematicsB
Grades on the NUST four-point scale, where A is 4.00 and B+ is 3.50. Degree awarded 2020 at cgpa 3.53 / 4.00.
What I do when I am not teaching
I am the founder of Ertiqah, which runs eight live software products used by more than 15,000 people, and I write the code. Not oversee it, write it. That means schema design, servers, deployment pipelines, third-party APIs, authentication, and the unglamorous business of keeping things running for people who are paying for them.
One of those products is PrepClubs, an exam-preparation platform used by more than 3,700 students. Building it meant thinking hard about how people actually learn under timed conditions, which turned out to be the most directly useful thing I have ever done for my teaching.
Where the engineering came from
2024 to now
Founder and engineer
Ertiqah
I build and run the products under Ertiqah myself, as the engineer rather than only as the founder. That is where the databases, servers, deployment pipelines, authentication and third-party APIs in the section below come from.
2022 to 2024
Presales Lead, EMEA and APAC
GFI Software
Ten or more security and networking products across two regions: network security, email security, patch and vulnerability management, network monitoring. More than 100 demos, webinars and on-site seminars delivered to enterprise buyers, among them NASA, the UK Government, the Ministry of Defence, Wipro and Tata Consultancy Services, and channel partners trained to deliver them afterwards. Firewalls and mail servers as a day job, not as a chapter.
2020 to 2022
L2 Technical Consultant
Trilogy
Around 500 escalated tickets across seven products: cybersecurity, network management, mail servers and archiving, bandwidth shaping, CRMs. Roughly 40 per cent resolved on first contact, at over 95 per cent customer satisfaction. Diagnosing someone else's broken system under time pressure is very close to what an exam question asks a student to do.
2019 to 2021
Head of Artificial Intelligence, then Chief Technology Officer
Ingenio
Ran the AI function and then the whole engineering organisation, hiring and managing more than 15 engineers across AI, web and mobile. I built the first product's pipeline end to end myself: scraping, preprocessing, analysis, model training, sentiment analysis and deployment.
2018 to 2021
AI and machine learning engineer, freelance
Upwork and others
More than $100,000 earned across 25 or more projects in machine learning and AI: object detection, classification models, data pipelines, and database design and development.
The part of the subject your specification barely covers
Almost every student I speak to wants to talk about AI, and the specifications give them very little to hold on to. Cambridge 9618, OCR H446 and AQA 7517 each touch it briefly and move on. I spent the first half of my career building this, which means the conversation can go past the headlines without leaving the syllabus behind: what a model is actually doing, why a neural network needs so much data, what training costs, and where the maths in the specification connects to it.
- Research
- A research fellowship in Artificial Intelligence with the University of Insubria in Italy, on multi-modal models for a paper, and close to two years as a research intern at the TUKL centre at NUST working on speech: separating who is speaking from whom, stripping the dead air out of conversational audio, and turning it into text.
- Computer vision
- Training a deep neural network from scratch with YOLO to recognise gym equipment and exercise posture, then shrinking it until it ran on a phone instead of a server. Collecting the images, annotating them, training, validating, and getting it working on the device.
- Machine learning in production
- As Head of AI and then CTO at Ingenio, sentiment analysis, classification and intent identification, optimised to chew through more than a million data points rather than a demo dataset.
- Today
- Every product I run has AI inside it, and one of them, Locul, exists to give large language models a memory. I work with these models daily, which is a different thing from having read about them.
None of this is on the exam paper, and I am not going to pretend it is. It matters for a different reason: a student who understands why the subject is built the way it is tends to stop memorising it, and that shows up in the marks.
Explaining this to people is not new
Being good at something and being able to teach it are different skills, and a page like this should be honest about which evidence it has. Mine is in technical training and community teaching rather than in a classroom.
- More than 25 webinars, workshops and technical talks delivered over five years, to industry professionals across EMEA and APAC and to university students.
- Speaking at industry conferences rather than only online: Optimus Solution Day in Bangkok, and the Ingram Experience across Sydney, Brisbane and Melbourne, a series drawing close to 7,000 attendees. The 2022 and 2023 webinar run covered email security, network performance and firewall as a service, some of it solo and some alongside a regional colleague.
- Beginner sessions I wrote and taught: Intro to C and Python, Intro to Python for AI, Intro to GitHub, Version Control Systems.
- GitHub Campus Expert, the programme GitHub runs to grow local technical communities.
- President of the ACM chapter at NUST, running an events programme that reached over 2,000 students, and co-founder of the Microsoft Learn Student Ambassadors chapter in Islamabad.
- A YouTube channel where I explain what I build, which has passed 150,000 views and 3,000 hours of watch time. The subject is software and marketing rather than the syllabus, but the evidence it offers is the relevant kind: people stay for the explanation.
What I do not have is a PGCE or a school post, and I would rather say so here than have you find out later. What I do have is the qualification itself at the top grades, the degree behind it, and the working experience that makes the answers concrete.
Eight products, and what each one forces me to know
This is not a list of things to buy. It is the reason the explanations in a lesson are specific. Every one of these had to be designed, built, deployed and then kept alive, and between them they cover most of what a Computer Science specification names.
Hydori
An official plugin in the WordPress.org directory, translating posts into 20 languages with correct hreflang on every version.
Third-party reviewed and publicly listed, so this is the one you can check without taking my word for it.
Contextli
A dictation app that turns speech into finished text inside whatever you had open, shipping on Mac, Windows, Linux, iPhone and Android.
Five platforms, operating-system level integration, and speech processing that runs on the device.
Locul
A local-first memory layer for AI tools that reads your own files and keeps itself current.
File systems, indexing and search, and running inference locally rather than in someone else's cloud.
Murkuz
An SEO platform that pulls Google Search Console, GA4 and Bing Webmaster data and publishes fixes back into WordPress, Webflow and Framer.
Authenticated third-party APIs, OAuth, rate limits, and reconciling data from sources that disagree.
Meisa
Behaviour-triggered lifecycle email that sends through your own provider: Amazon SES, SendGrid, Mailgun or plain SMTP.
SMTP, deliverability and mail headers. The networks chapter, with consequences.
Kamaan
A blog and help-centre platform that publishes once and serves 99+ languages, with a REST API for any framework.
REST API design, content modelling and internationalisation.
testimonials.ltd
Video and written review collection, with eight embeddable widget formats and a hosted wall of reviews.
Media capture and storage, and embedding safely on sites you do not control.
LigoSocial
A LinkedIn writing and engagement tool, as a web app plus a Chrome extension.
Browser extension APIs and manipulating a page's DOM from outside the page.
Every one of them also ships a server that Claude and ChatGPT can drive directly, which is a client-server architecture problem of exactly the shape the specification describes and almost never illustrates with anything a student has heard of.
Where the specification and a working codebase overlap
A syllabus topic on the left, with the degree module behind it and the grade I got, and on the right what that same topic is in an ordinary working week. This is the part a tutor who only teaches cannot offer, and it is the reason explanations in a lesson tend to arrive with a reason attached.
- Databases and SQLCS-220 Database Systems, grade A
- Designing schemas and writing queries against the live databases behind eight products, and finding out the hard way which missing index turns a 20 millisecond query into a 20 second one. Normalisation stops being an exam ritual once you have had to migrate a table that was not normalised.
- Networks and protocolsEE-353 Computer Networks, B+ and EE-322 Wireless Networks, B+
- DNS records, HTTP headers, TLS certificates, reverse proxies and CDNs, configured rather than memorised. Meisa sends over SMTP through whichever provider a customer brings, so mail protocol is a support ticket rather than a diagram. When a question asks what a packet carries or why a request failed, the answer comes from having read the failing request.
- SecurityCS-381 Network Security, grade A
- Password hashing, authentication tokens, OAuth against Google and Microsoft, firewall rules and web application firewalls on systems more than 15,000 people log in to. The syllabus asks for the definition of a brute-force attack; production asks you to stop one.
- Systems software and architectureCS-330 Operating Systems, B+ and EE-321 Computer Architecture, B+
- Linux servers, containers, process supervision, memory limits and the reason a machine falls over at 3am. Contextli ships on Mac, Windows, Linux, iPhone and Android, which is five operating systems disagreeing about the same task. Virtual memory and scheduling are on the specification because they explain behaviour you can watch.
- Algorithms and complexityCS-250 Data Structures & Algorithms and CS-251 Design & Analysis of Algorithms, both B+
- Where a nested loop is entirely fine and where it takes a page down. Big O is worth marks in an exam and worth money in a codebase, and the second one is what makes it stick.
- Object-oriented programmingCS-212 Object Oriented Programming, grade A
- Classes, inheritance, interfaces and composition in codebases that have to be maintained by someone else later. Most students can define encapsulation. Far fewer can say what goes wrong without it, which is what the higher mark bands ask for.
- Programming and testingCS-110 Fundamentals of Computer Programming and SE-321 Software Quality Engineering
- Python, TypeScript and SQL, most days. Reading a stack trace, forming a hypothesis and proving it is the same skill as an exam question that hands you nine lines of broken code and asks you to state the error.
Guides I have written, and how
Everything on this site is built from the exam boards’ own specifications and published guides, not from other revision sites. That is slower, and it is the only way to catch the places where the summaries circulating online are simply wrong.
OCR Exam Reference Language
OCR's GCSE specification and its A-Level appendix print two different versions of Exam Reference Language, and they disagree on files: at GCSE writeLine adds to the end of a file, at A-Level openWrite overwrites it. The guide works through every construct against Python.
Read the guide →Pseudocode across exam boards
Cambridge's 9618 pseudocode guide is not what candidates get in the exam room: the Paper 2 insert supplies a different set of string functions, and examiners penalise Python habits such as LEN() and FOR ... IN. Built from the boards' own guides and examiner reports, with OCR, AQA and Python alongside.
Read the guide →A-Level NEA project ideas
Eleven project ideas that clear the mark scheme and five popular ones that quietly do not, worked out from what the assessment criteria actually reward rather than from what looks impressive.
Read the guide →
What I help with, and what I will not do
Lessons cover theory, programming, exam technique and past-paper work, and for A-Level students the NEA coursework project. On the NEA that means planning, structuring, debugging your own code and reviewing your write-up against the mark scheme.
It does not mean writing it. Supplying coursework is against exam board rules and, in England, against the law. A tutor who offers to write your project is offering to get you disqualified, and the work would not survive a moderator reading it next to your interview notes anyway.
Start with a free introductory call
Tell me the board, the paper and what is not landing. We will use the call to work out whether I am the right person for it, which is a question with a real answer either way. Lessons are £60 an hour over Zoom, with nothing to commit to up front.