jsonfmt.dev vs JSONZen

jsonfmt.dev is a web-based JSON formatter, beautifier and validator, with an HTTPS API for JSON processing. The formatter offers 2-space, 4-space or tab indentation, optional key sorting and depth control. It validates JSON against RFC 8259 and reports line and column errors. Other tools can repair common malformed JSON, compare two documents and convert formats including YAML, CSV, XML, TypeScript, SQL, GraphQL and Protobuf. The toolkit also includes a JWT decoder, JSON Schema validator, JSONPath evaluator and JSONL tools. The maker says the core browser tool handles JSON locally without sending its contents to the server, and continues to work offline after loading; it can also be installed as a Progressive Web App. API options include anonymous access limited to 10 requests per minute, a free API key tier with 100 requests per minute and 1,000 per month, and Pro API at $9, paid once for 1,000 requests per minute and 50,000 per month. Share links encode JSON in the URL fragment, and anyone with the link can access its contents.

JSONZen is a browser toolkit for formatting, validating, comparing, querying and converting JSON. Its tools also include minification, a tree view, JWT decoding and code generation for TypeScript, Zod, Pydantic v2 and JSON Schema. The site says core tools run in the browser and require no signup. Validation supports JSON Schema drafts 07, 2019-09 and 2020-12, with errors reported by path. Queries can use JSONPath and JMESPath; jq querying is listed as a Pro tool. Share links place their payload in the URL fragment rather than on JSONZen’s servers. Free share links allow up to 32 KB, and Free users can store three snippets locally per browser. Pro adds encrypted cloud-synced snippets, with manual syncing per snippet and a 2 MiB ciphertext limit per snippet. The listed Free plan is free, billed Forever. Pro is listed at $1.00 USD once for 30 days as a launch promotion, with no auto-charge; the pricing note lists paid plans from $5/mo. The CLI is included free.