json0

Guides

13 guides on comparing, cleaning and converting JSON, CSV and MongoDB data, with the json0 tool for each. Every guide is also available as Markdown, and llms.txt lists them all.

Comparisons

6 guides
  • JSON diff tools compared

    Five ways to compare two JSON documents, tested on the same pair of API responses. What each one shows, how it treats key and array order, and where your data goes.

    6 min read
  • MongoDB JSON without a database

    Extended JSON, ObjectId timestamps, testing a find filter and checking a collection's schema. Which jobs need Compass or mongosh, and which you can do on pasted documents in the browser.

    4 min read
  • Redact JSON before you share it

    Before you paste a payload into a ticket, a chat or an AI assistant, strip the keys, tokens and customer details. Four ways to do it compared: json0 Redact, jq, Microsoft Presidio and gitleaks.

    5 min read
  • json0 vs JSONLint

    Both validate JSON and both keep your data in the browser. JSONLint reports every error at once and has a repair tool; json0 loads no ads or trackers and adds diff, tables, schemas and more. A side-by-side comparison.

    5 min read
  • json0 vs JSON formatter sites

    Formatter sites such as jsonformatter.org pretty-print in the browser but load dozens of ad and tracking services, and their save feature can make your JSON public. How json0 compares, and where the big formatter sites are still the better pick.

    5 min read
  • json0 vs jwt.io

    jwt.io decodes, verifies and creates JSON Web Tokens and is backed by Auth0. json0 decodes them on a page with no ads, analytics or third-party requests, and never asks for your signing secret. What each does, what we measured, and which to use.

    4 min read

How to

7 guides
  • Compare JSON, ignoring array order

    When ["a","b"] and ["b","a"] should count as equal, and when they should not. Three ways to diff JSON with unordered arrays, and the edge cases that trip each one up.

    4 min read
  • JSON to CSV, with nested objects

    Turn an API response into a spreadsheet without losing nested fields. How flattening to dot paths works, what to do with arrays, and how to do it in the browser, with jq or with pandas.

    3 min read
  • Types and schemas from a JSON sample

    Infer types from real API responses instead of writing them by hand. What a generator can and cannot know from a sample, how to feed it several samples, and how to check the result.

    4 min read
  • Compare two CSV files by a key column

    A line diff of two exports is useless once rows are re-sorted. Match rows on an id column instead and list the rows added, removed and the exact cells that changed. In the browser, with csv-diff or daff, or in a spreadsheet.

    3 min read
  • The time inside a MongoDB ObjectId

    Every ObjectId carries its creation time. How to read it in mongosh, JavaScript and Python, how to build an _id range for a time window, and the caveats that come with using _id as a clock.

    3 min read
  • Decode a JWT safely

    Anyone can decode a JSON Web Token without a key. That does not make its contents true. What the header, payload and signature tell you, how to read exp and iat, and how to inspect a token without leaking it.

    4 min read
  • JSONPath cheat sheet

    The JSONPath syntax you will actually use, tried on one real API response, with each result shown, the standard RFC 9535 filter syntax, and the jq command that does the same thing.

    3 min read

What json0 does

20 tools, all in the browser
ToolWhat it does
JSON DiffCompare two JSON documents side by side and see every added, removed and changed key, with array order optional. Runs locally in your browser; nothing is uploaded.
JSONPath QueryRun JSONPath expressions against a JSON document and see each match with its path. Runs locally in your browser; nothing is uploaded.
JSON ValidatorValidate JSON and get the exact line, column and reason for every syntax error, with the broken lines shown. Runs locally in your browser; nothing is uploaded.
JSON FormatterPretty-print, minify, sort keys, or escape and unescape JSON as a string, with the size before and after. Runs locally in your browser; nothing is uploaded.
JSON to TableTurn a JSON array into a sortable, filterable table with nested objects flattened into columns, then copy it as CSV, TSV or Markdown. Runs locally in your browser.
JSON Schema GeneratorInfer a JSON Schema, TypeScript types and a Zod schema from sample JSON, then validate documents against it. Runs locally in your browser; nothing is uploaded.
XML to JSON ConverterConvert XML to JSON with attributes and text kept and repeated elements turned into arrays. Runs locally in your browser; nothing is uploaded.
CSV ViewerOpen a CSV or TSV file as a table, profile every column, find and remove duplicate rows, and convert it to JSON or NDJSON. Runs locally in your browser.
CSV DiffCompare two CSV exports row by row on a key column and see the rows added, removed and every changed cell. Runs locally in your browser; nothing is uploaded.
MongoDB Extended JSON ConverterConvert between mongosh shell syntax, canonical and relaxed Extended JSON v2 and plain JSON, keeping ObjectId, Date, Long and Decimal128 types. Runs locally in your browser.
MongoDB ObjectId DecoderRead the creation time inside MongoDB ObjectIds, generate ObjectIds for a date, and build an _id range filter for a time window. Runs locally in your browser.
MongoDB Query TesterTest a MongoDB find filter, projection, sort and limit on pasted documents and see which ones match, without a database. Runs locally in your browser.
MongoDB Schema AnalyzerSee every field across a set of MongoDB documents with its types, how often it is present, and which fields have mixed types to fix. Runs locally in your browser.
JSON and CSV RedactorFind emails, phone numbers, card numbers, IBANs, API keys, JWTs and IP addresses in JSON or CSV, then mask, fake, hash or remove them. Runs locally in your browser.
Base64 Encoder and DecoderEncode text to Base64 or decode it back, with UTF-8 handled and an optional URL-safe alphabet. Runs locally in your browser; nothing is uploaded.
JWT DecoderDecode a JSON Web Token and read its header, payload and claims, with issue and expiry times in plain dates. Runs locally in your browser; nothing is uploaded.
Hash GeneratorCompute SHA-1, SHA-256, SHA-384 and SHA-512 digests of any text with the browser’s Web Crypto. Runs locally in your browser; nothing is uploaded.
UUID GeneratorGenerate up to 50 version 4 UUIDs at once from crypto.randomUUID, in lower or upper case, and copy them all. Runs locally in your browser.
IP Address InspectorRead an IPv4 or IPv6 address locally: its version, its range (private, shared, loopback, public and more) and its integer, hex and binary forms. Nothing is uploaded.
Ping ToolCheck whether a host answers and how fast: three timed HTTPS requests from your browser, since browsers cannot send ICMP pings. Nothing is sent until you press Ping.