Technical Sourcer | Engineering (Contract)

A browsable practice library of coding problems that can be filtered by pattern, data structure, difficulty and company, so you can drill exactly the weakness you found this week. Patterns include two pointers, sliding window, hash maps, stacks, backtracking and greedy algorithms, with company filters for Google, Meta, Microsoft, Amazon, Oracle and LinkedIn. Free to browse, with an in-browser editor and solutions.

• Job search
• DSA

A course built around 75 coding interview questions chosen for coverage across 18 topic areas, from arrays and sliding window to graphs, backtracking, dynamic programming and tries. Each question has a step-by-step algorithm, a walkthrough and complexity analysis, with solutions in six languages. It suits candidates with a few weeks before an interview who need a balanced, finite problem set rather than an endless list.

• Job search
• DSA

A free newsletter of short, focused posts on system design and problem solving, from the team behind the Grokking courses. Recent posts cover company interview processes (such as OpenAI and Anthropic roles), the most asked mobile system design questions and preparation plans, each linking to a fuller article on the blog. It suits engineers who want a steady, low-effort way to keep system design and interview topics fresh between deeper study sessions.

• System design
• DSA

A very large site of articles on data structures, algorithms and core CS subjects such as operating systems, DBMS, computer networks and OOP, usually with code in several languages, plus practice problems and paid courses. It is handy for revising a university topic or finding a worked example of a specific algorithm. Quality varies because much is community written, so cross-check anything surprising against a textbook or official documentation.

• DSA
• CS fundamentals
• Databases

An eight-stage roadmap through the core CS subjects: how a computer runs a program, OOP and design, operating systems, computer networks, database theory and internals, software engineering and theory, finished with a systems project such as a shell, an HTTP server or a tiny database. It suits CS students and self-taught developers filling the same gaps, and favours understanding shown in working code over memorised answers.

• DSA
• CS fundamentals
• Databases

The second volume of Grokking the System Design Interview, aimed at senior and staff (L5/L6) design rounds. It works through harder case studies such as a payment system, flash sale, notification service, unique ID generator, Gmail, Reddit, Google Calendar and a code judging system, then goes beneath them with patterns like quorum, write-ahead logs and vector clocks and deep dives into Dynamo, Cassandra, Kafka, Chubby, HDFS, GFS and BigTable.

• System design
• Backend
• Job search