Reference · 7 min read
Does Minifying JSON Matter If You Use Gzip?
Almost every guide tells you to minify JSON to save bandwidth. Almost none of them measure what happens after the compressor has had its turn.
JSON guides and references
Working notes on the parts of JSON that actually cause problems — parse errors, schema evolution, array diffing, type inference and the Excel behaviours that quietly corrupt a CSV export. Each article links to the tool that does the job.
- Reference · 8 min read
The YAML Norway Problem, and When It Applies
A list of country codes, a YAML parser, and Norway quietly turns into false. The famous version of this story is true — but whether it happens to you depends entirely on which parser you are holding.
- Workflow · 8 min read
Why Excel Turns Your CSV IDs into 1.23E+18
The CSV is correct. Excel changes it during import, silently, and saving the file makes the damage permanent.
- Fundamentals · 8 min read
JSON and Large Numbers: Where the Precision Goes
The JSON spec puts no limit on the size of a number. Every mainstream parser does. The gap between those two facts is where production bugs live.
- Workflow · 8 min read
Unexpected Token < in JSON: What It Means
If the unexpected token is `<`, you are not looking at a JSON problem. You are looking at an HTML page where JSON should have been.
- Fundamentals · 7 min read
Can JSON Have Comments? What to Use Instead
JSON had comments for about a year. Douglas Crockford removed them on purpose, and his reason was not about syntax.
- Reference · 7 min read
Why Sorted JSON Keys Come Out in the Wrong Order
You asked for alphabetical. You got "2", "10", "A", "Z", "_x", "a", "b". Two separate rules are fighting, and both of them are working correctly.
- Reference · 7 min read
NDJSON: One JSON Document Per Line
One big array has to be complete to be worth anything. Lose the last byte and you lose every record. NDJSON costs nothing to adopt and does not have that property.
- Workflow · 8 min read
How to Open a Large JSON File
Your editor is not slow at parsing JSON. It is slow at drawing it. Those are different problems with different solutions.
- Reference · 6 min read
Duplicate Keys in JSON: Valid, Silent, Dangerous
No error, no warning, no clue. One value wins, the others vanish, and every tool you own reports the document as valid.
- Fundamentals · 7 min read
JSON, Unicode and Why Your Emoji Has Length 2
"😀".length is 2, and that is not a JavaScript quirk — it is the same reason your database column overflowed.
- Comparison · 6 min read
JSON Pointer vs JSONPath: Which One to Use
They look like they do the same job. One is a precise address for a single value; the other is a query that may match hundreds. Picking wrong makes everything downstream awkward.
- Workflow · 8 min read
How to Debug an API JSON Response
Most “the API is broken” incidents are a field that changed type, a field that went missing, or a null nobody expected.
- Workflow · 7 min read
How to Generate TypeScript from JSON
Generated types are inference from evidence. The quality of the output is entirely determined by the quality of the sample.
- Reference · 9 min read
JSON Schema Explained, From Sample to Contract
A generated schema describes the sample you gave it. A useful schema describes the agreement you actually want to enforce.
- Workflow · 7 min read
How to Convert JSON to CSV Without Losing Data
CSV is flat and JSON is a tree. Everything difficult about the conversion follows from that one sentence.
- Reference · 8 min read
JSONPath Explained, With Runnable Examples
JSONPath is XPath for JSON: a compact way to say “every email address in this document”, whatever shape it is in.
- Workflow · 7 min read
How to Compare Two JSON Files Properly
Reorder a few keys and `git diff` says every line changed. A structural diff says nothing changed — because nothing did.
- Comparison · 7 min read
JSON vs YAML: Which to Use and When
JSON for machines, YAML for humans — with a short list of YAML behaviours that have caused real outages.
- Fundamentals · 7 min read
How to Validate JSON: Syntax and Schema
“Unexpected token } in JSON at position 582” is a true statement and a useless one. Here is how to get from it to the actual problem.
- Workflow · 6 min read
How to Format JSON (and When Not To)
Formatting changes nothing but whitespace — which is exactly why choosing the right moment to do it matters.
- Fundamentals · 8 min read
What Is JSON? A Practical Guide for Developers
JSON is small enough that its entire grammar fits on one page — which is exactly why the edge cases catch people out.