Question 1

What is JSON Lens?

Accepted Answer

JSON Lens is a free online tool for working with JSON data. It lets you format and validate JSON, browse it in a tree or table view, run SQL-like queries, diff two JSON files side by side, and generate bulk email templates from JSON arrays.

Question 2

Can I query JSON with SQL?

Accepted Answer

Yes. JSON Lens includes a built-in SQL-like query engine. You can write queries such as SELECT name, age FROM data WHERE age > 25 ORDER BY name LIMIT 10, as well as GROUP BY, aggregates (COUNT, SUM, AVG, MIN, MAX), LIKE, IN, IS NULL, and dot-notation for nested fields.

Question 3

How do I compare two JSON files?

Accepted Answer

Click the Diff tab in JSON Lens, paste your original JSON in the left panel and your modified JSON in the right panel, then click Compare. The tool highlights added, removed, changed, and type-changed keys with a similarity percentage.

Question 4

Is JSON Lens free to use?

Accepted Answer

Yes, JSON Lens is completely free. It runs entirely in your browser — no sign-up, no account, and no data is sent to any server.