How to Fix Invalid JSON Errors
Learn how to find and fix missing commas, unquoted keys, trailing commas, invalid escapes, hidden characters, and other common JSON errors.
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Developer Guides
14 focused guides across 13 developer tool topics, with each guide connected to the browser-local tool and troubleshooting context it supports.
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14 focused guides
JSON topic
JSON guides
Format, inspect, and query JSON with configurable indentation, key sorting, validation, and JSONPath selection.
JSON Escaping Explained: Quotes, Backslashes, Newlines & Unicode
Learn how JSON escaping works for quotes, backslashes, control characters, newlines, Unicode escapes, and double-encoded JSON with practical examples.
Read guideJSONL topic
JSONL guides
Validate newline-delimited JSON, preview it as an array, normalize one record per line, or convert a JSON array to JSONL.
JSON vs JSONL: Differences and Examples
Compare JSON and JSONL structure, examples, streaming behavior, error handling, and the situations where each format is the better choice.
Read guideBase64 topic
Base64 guides
Encode UTF-8 text or hexadecimal bytes as Base64, create unpadded URL-safe Base64 (Base64URL), or decode Base64 as UTF-8 text or hexadecimal bytes locally.
Base64 vs Base64URL: What Changes?
Understand the Base64URL alphabet, padding rules, JWT usage, UTF-8 decoding, and how to convert safely between standard Base64 and URL-safe Base64.
Read guideTimestamp topic
Timestamp guides
Convert Unix timestamps in seconds, milliseconds, microseconds, or nanoseconds and parse ISO 8601 dates. Inputs without an offset use UTC.
Unix Timestamp Seconds vs Milliseconds
Learn how to identify 10-digit and 13-digit Unix timestamps, convert between seconds and milliseconds, and avoid timezone mistakes.
Read guideRegex topic
Regex guides
Test regular expressions, inspect every match, and replace text with JavaScript RegExp syntax locally.
JavaScript Regex Cheat Sheet: Syntax, Flags & Examples
JavaScript regex quick reference for character classes, anchors, quantifiers, groups, lookarounds, flags, replacements, and copyable examples.
Read guideJWT topic
JWT guides
Decode JWT headers and payloads locally and inspect exp, nbf, and iat time status.
JWT Decode vs Verify: Why Decoding Is Not Verification
Learn the difference between decoding and verifying a JWT, what signature verification proves, and why issuer, audience, and time claims still need validation.
Read guideYAML topic
YAML guides
Format, validate, and convert YAML and JSON locally with YAML 1.2 parsing.
YAML Indentation Explained: Spaces, Sequences & Mapping Errors
Learn how YAML indentation defines mappings, sequences, nested blocks, and multiline scalars, with examples for tabs, spacing, and common parser errors.
Read guideXML topic
XML guides
Format and validate XML, convert XML to JSON, or create XML from JSON entirely in your browser.
XML Parsing and Validation Errors Explained
Understand XML parsing and well-formedness errors, how to read parser messages, and how tags, entities, attributes, namespaces, and document structure cause validation failures.
Read guideCSV topic
CSV guides
Format and validate CSV, convert CSV to JSON, or turn JSON into spreadsheet-ready CSV locally.
CSV Quoting, Delimiters, and Column Rules Explained
Understand CSV quoting, comma, semicolon, and tab delimiters, consistent column counts, header rules, multiline fields, and safe CSV-to-JSON conversion.
Read guideQuery String topic
Query String guides
Parse query parameters into JSON, build encoded query strings, clean and sort parameters in one pass, or run focused sorting and cleanup operations.
Query String Encoding and Repeated Parameters Explained
Understand query string percent encoding, plus signs, repeated parameters, empty values, fragments, and how JSON arrays map to repeated query keys.
Read guideUUID topic
UUID guides
Generate random UUID v4 or time-ordered UUID v7 values, validate UUID versions, and inspect embedded UUID v7 timestamps locally.
UUID Versions, Variants, and Validation Explained
Understand UUID versions 1 through 8, RFC variant bits, canonical UUID text, and what structural UUID validation can and cannot prove.
Read guideHash topic
Hash guides
Generate common digests from UTF-8 text or decoded Hex and Base64 bytes with browser-local processing.
Hashing Text vs Bytes: Encoding Pitfalls Explained
Learn why hashes depend on exact bytes, how UTF-8 encodes text, and why BOMs, Unicode normalization, line endings, hex, and Base64 cause hash mismatches.
Read guideSQL topic
SQL guides
Expand dense queries into readable SQL with selectable dialect and keyword casing, or compress them again.
SQL Formatting vs Validation: What a Formatter Can and Cannot Check
Learn the difference between formatting SQL and validating it, including dialect syntax, schema checks, execution errors, query safety, and a practical review workflow.
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