Developer Guides
Short, practical guides for common developer tasks. Learn how to work effectively with JSON, XML, APIs, and more.
JSON Guides
How to validate JSON (and fix common errors)
Understand what “invalid JSON” means and how to quickly fix the most common mistakes.
Read guide →How to pretty print JSON
Turn minified JSON into readable, indented output, choose an indent size, and avoid common formatting mistakes.
Read guide →How to minify JSON
Remove whitespace from JSON to shrink payloads, when minifying actually helps, and when you should keep JSON readable.
Read guide →Sort JSON keys (when and why)
Clean up diffs and reviews by sorting object keys—plus when to avoid it.
Read guide →How to share JSON data with others
Create a link that opens your JSON in the formatter, understand how share links work, their size limits, and how to share data safely.
Read guide →How to compare two JSON files
Tips for getting clean diffs, sorting keys, and avoiding noise in comparisons.
Read guide →JSONPath examples
Example paths for nested objects and arrays, plus how to think about paths when debugging APIs.
Read guide →Escape JSON strings
Escape quotes, backslashes, newlines and Unicode characters in JSON strings correctly, with examples of each case.
Read guide →Handle large JSON (performance tips)
Practical ways to open, format, search and compare very large JSON files in the browser without freezing the tab.
Read guide →JSON vs YAML
JSON vs YAML compared side by side: syntax, comments, typing pitfalls, and when to choose each for configs and APIs.
Read guide →JSON privacy & safety tips
How to sanitize JSON before sharing it, which fields leak secrets most often, and safe habits for debugging with real data.
Read guide →Redact / sanitize JSON (remove secrets safely)
Redact tokens, emails and personal data from JSON while keeping its structure and IDs useful for debugging.
Read guide →NDJSON / JSON Lines explained
What NDJSON / JSON Lines is, how it differs from a JSON array, and why logs and streaming pipelines use one object per line.
Read guide →API error JSON payload patterns
Consistent error shapes with codes, field-level details, and trace IDs.
Read guide →API JSON best practices
Practical conventions for JSON APIs: field naming, nulls vs missing fields, dates, pagination, error shapes and versioning.
Read guide →JSON Schema basics
Use JSON Schema to validate the structure of JSON, not just its syntax: types, required fields, enums and nested objects.
Read guide →JSON data types explained
The six JSON value types, how they map to JavaScript, Python, Java and Go, and how to represent dates, money, large integers and binary data.
Read guide →Parse and stringify JSON in JavaScript
How JSON.parse and JSON.stringify really behave: revivers, replacers, toJSON, dropped values, BigInt, dates and common pitfalls.
Read guide →Work with JSON in Python
Read and write JSON with Python's json module: type mapping, pretty printing, datetime and Decimal handling, and decoding errors.
Read guide →Fix "Unexpected token" and other JSON parse errors
What "Unexpected token < in JSON at position 0" and other parse errors mean in browsers, Node.js and Python, and how to fix each one.
Read guide →Dates and times in JSON
How to send dates and times in JSON: ISO 8601 strings, UTC, date-only values, time zones and the pitfalls of Unix timestamps.
Read guide →Convert JSON to CSV (and back)
Turn JSON into CSV: flattening nested objects, handling arrays, CSV escaping rules, Excel quirks, and examples in Python and jq.
Read guide →JSON Pointer, JSON Patch and Merge Patch
Point at values with JSON Pointer (RFC 6901) and describe changes with JSON Patch (RFC 6902) or JSON Merge Patch (RFC 7396).
Read guide →XML Guides
How to use the XML Formatter
Format, minify and validate XML in your browser, check it against an XSD schema, compare documents and convert XML to JSON.
Read guide →How to format and validate XML
Learn the basics of XML formatting, common syntax errors, and how to keep your XML documents well-formed.
Read guide →XML vs JSON: When to use which
A comparison of XML and JSON formats, their pros and cons, and common use cases.
Read guide →Web & Network Guides
Understanding User-Agent strings
Learn how to read and parse User-Agent strings to identify browsers, operating systems, and devices.
Read guide →How IP Lookup and Geolocation works
Understand how IP addresses are mapped to physical locations and the limitations of this technology.
Read guide →JWTs explained: decode JSON Web Tokens
How a JSON Web Token is built, how to decode its header and payload, what the standard claims mean, and how to verify tokens safely.
Read guide →CORS errors explained (and how to fix them)
Why browsers block cross-origin requests, what preflight requests are, what common CORS error messages mean, and how to fix them on the server.
Read guide →API & GraphQL Guides
Best practices for testing REST APIs
What to test in a REST API, how to structure requests and authentication, and a workflow from manual checks to automated tests in CI.
Read guide →Introduction to GraphQL queries
Learn the basics of GraphQL, how it differs from REST, and how to write your first queries and mutations.
Read guide →GraphQL vs REST: when to use which
A practical comparison of GraphQL and REST: data fetching, caching, errors, tooling and the costs each approach brings to a project.
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