https://tableconvert.com/ Show archive.org snapshot is an online tool to convert tables between different formats (e.g. json, markdown, csv).
It also has a button to transpose a table ("rotate" it by 90 degree).

Do you need DevOps-experts?

Your development team has a full backlog? No time for infrastructure architecture? Our DevOps team is ready to support you!

• We build reliable cloud solutions with Infrastructure as code
• We are experts in security, Linux and databases
• We support your dev team to perform

Read more Show archive.org snapshot

The tool can be handy if you have tests with large markdown tables for testing contents of a flat json structure or csv.

Please note that you should not use it with sensitive data (like all online tools in general).