JSON Formatter
Articles, guides, and in-depth tips for the JSON Formatter — everything you need to get the most out of it.
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Unexpected Token at Position 847: Debugging JSON Errors
Why JSON Parses Differently in JavaScript, Python, and Go — Precision, Duplicates, and Parser Security
JSON's specification deliberately leaves number precision, duplicate key handling, and Unicode surrogate pairs as implementation-defined — which is why identical JSON produces different results in JavaScript (integers lose precision above 2^53), Python (arbitrary precision integers), and Go (float64 by default). Here's the parser differential security attack from duplicate keys, prototype pollution via JSON merge, and why NDJSON enables streaming gigabyte datasets with constant memory.
Why JSON Doesn't Allow Comments — and the JSON5/JSONC Variants That Do (and Why They Break Standard Parsers)
JSON5 and JSONC add comments and trailing commas to JSON — and if you've ever tried to add a // comment to a tsconfig.json and wondered why VS Code allows it but JSON.parse() doesn't, you've encountered the JSON variant ecosystem. Here's why JSON has no comments by design, the three overlapping "JSON with comments" specifications, why standard parsers reject JSONC content, and the preprocessing approaches for handling these variants in automation.
Structured JSON Logging: How to Debug Production API Errors and Search Logs at Scale
Structured JSON logs are queryable across millions of events in milliseconds; unstructured string logs require brittle grep. Here's why JSON logging matters, the OpenTelemetry log schema standard, structured logging libraries in Python/Node/Go, and how formatting API error responses reveals everything needed to debug a production incident.
Why 9007199254740993 Becomes 9007199254740992: JSON Numbers and JavaScript's Precision Limit
A JSON number like 9007199254740993 can become 9007199254740992 just by being parsed in JavaScript — not a bug in the parser, but a mismatch between JSON's unlimited-precision number specification and JavaScript's double-precision floating point, which can't represent integers above 2^53 exactly. Here's why this specifically affects large database IDs, the common "represent as string" workaround, and why this creates cross-language inconsistencies when backends and JavaScript frontends disagree about what "the same number" means.
JSON Schema Validation and API Contracts: OpenAPI, Contract Testing, and Validation Libraries
JSON Schema validates structure and constraints — and OpenAPI uses it as the contract format for API documentation, client SDK generation, and contract testing. Here's how JSON Schema works, key validation keywords, how OpenAPI extends it, and how Pact implements consumer-driven contract testing.
JSON vs YAML vs MessagePack vs Protocol Buffers: Which Format for Which Use Case
JSON has no comments, no date type, and a number precision problem that caused Twitter to change their API. Here's how JSON compares to XML, YAML, MessagePack, and Protocol Buffers, when each format makes sense, and what JSON Schema adds.
JSON Formatter — Pretty Print, Minify & Validate JSON Instantly
Learn how a JSON formatter works, what common JSON syntax errors look like, the difference between JSON and JavaScript objects, and how to format and validate JSON instantly with a free tool.
