Validate RFC 8259 JSON syntax with line hints, duplicate-member and precision warnings, plus an explicit schema and API-contract boundary.
Choose your path
Accept or reject one bounded JSON text with reproducible syntax location evidence while separating RFC 8259 interoperability warnings from JSON Schema, API-contract and downstream-parser acceptance.
Locate a syntax failure and preserve the exact input for a separate schema/integration run.
Paste a versioned example, read syntax and line/column status, correct it, then save the three-field Project record.
Can reproduce parser acceptance without calling it schema or API validity.
See valid-syntax hazards that common parsers can collapse or round.
Exercise duplicate names and precision-sensitive numbers, inspect RFC evidence and record warnings before approval.
Does not accept a green syntax state as lossless or interoperable evidence.
Operate one focused validator without formatter, repair, XML or tree distractions.
Use the labeled JSON editor, textual live status, warnings, sources and Project save at desktop and mobile widths.
Completes the task with named controls, non-color status and no horizontal overflow.
Outputs and checklists are planning aids. Review the linked current authorities and the records, terms, instructions, and requirements that apply to your exact situation before a consequential decision.
This tool is part of these guided projects. Each project provides step-by-step instructions with checklists and all the tools you need in one place.
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A syntax pass is not JSON Schema, API-contract, policy, security, authorization, encoding-transport, or downstream-parser acceptance. Those checks remain with the target system.
Updated: July 2026
An API implementer reproduces a versioned example, fixes the reported syntax location, then reruns schema and integration tests outside this Tool.
A reviewer checks duplicate-member and precision warnings before accepting a parser pass as evidence for a consumer contract.
A technical writer records that the example is syntax-valid while linking the separate schema version, consumer evidence, and known parser limits.
Check one JSON text against browser ECMAScript parsing, then review RFC 8259 interoperability warnings separately from schema, policy, and consumer acceptance.