About
About DataDank
A learning system for Data Engineers, organised as paths rather than a pile of articles.
What this is
DataDank brings learning paths, technology guides, interview preparation, system-design case studies and projects into one structure. Every page points to a prerequisite, related ideas and a next step.
Launch focus
The site starts with Data Engineering only: SQL, Python, Spark, warehousing, lakehouse, streaming and orchestration. Other data careers will be added only once Data Engineering content is complete and useful.
Who runs DataDank
DataDank is an independent project with a single maintainer. It is not affiliated with, sponsored by or endorsed by any of the companies or vendors whose tools it teaches, and it has no paid placements or affiliate links.
How content is written and reviewed
Pages are written to answer one clear question. Technical claims are checked against official documentation, which is linked in each page's sources. Runnable SQL, Python and PySpark examples are executed before publishing, and the page states the versions they ran on. Where behaviour depends on a version or platform release, the page says so. Each page shows when it was last reviewed, and that date only changes after a substantive update.
AI tools help with outlines, drafting and wording. They do not replace running the examples, checking the documentation or editorial review, and no page is described as expert-reviewed unless that review has happened.
Practice problems and external links
DataDank's explanations and solutions are its own. Where a problem also exists on a judge site such as LeetCode or DataLemur, the page links to it so you can run your solution against their tests; their problem statements, test cases and editorials are not copied.
How company interview material is labelled
Company guides distinguish three kinds of information: verified or attributed facts that cite a public source, reported items that cite a named candidate account, and representative practice questions that we wrote ourselves. Practice questions are never presented as questions a company actually asked.
Report a problem
Found a factual error, outdated behaviour or a broken link? Email the address on thecontact page with the page address and, if possible, a link to the documentation that shows the correct behaviour. Confirmed errors are fixed on the page.