AI DEVELOPMENT WORKSPACE
Chat Messages JSON Validator
Check a dated OpenAI Chat Completions text-only structure subset.
Validation profile: openai-chat-text-2026-10-19 · restricted OpenAI Chat Completions subset. Unsupported means outside this checker. Formatting has no provider-validation guarantee.
Input is processed on this site only when you run the tool. The application does not save inputs or results.
input.json
Result result.json
A little clarity goes here.
Run the tool to see your result.
Result preview
UTF-8 text, at most 65536 bytes per input. Tab leaves the editor. Plain text disables syntax colors. Browser textareas may normalize line endings to LF.
{"validate":{"inputMode":"text","options":[],"inputLabels":[]}}{"validate":{"input":"[{\"role\":\"developer\",\"content\":\"Use fictional examples.\"},{\"role\":\"user\",\"content\":\"Explain this note.\"}]","options":[]}}A QUICK WALKTHROUGH
A familiar workflow,
with room to focus.
Paste a JSON messages array with unique object keys.
Validate against the named text-only profile.
Read valid, invalid or unsupported and the first diagnostic pointer.
When to use Chat Messages JSON Validator
Check a simple text-only messages fixture against the explicitly named local Chat Completions profile.
Read the result
Read status together with profile and scope. Unsupported is outside this checker, while valid covers only its structural subset; neither is a live model or authorization check.
SEE IT IN PRACTICE
Worked examples
Sample input. A result you can inspect.
Validate example
Input
[{"role":"developer","content":"Use fictional examples."},{"role":"user","content":"Explain this note."}]Expected result
{"profile":"openai-chat-text-2026-10-19","status":"valid","diagnostic":null,"scope":"Restricted offline structure check only; not full API, model, instance or conversation-semantic validation."}{"kind":"validation","title":"Structure check passed","tone":"success","note":"Restricted offline structure check only; not full API, model, instance or conversation-semantic validation.","copy":"Structure check passed\nRestricted offline structure check only; not full API, model, instance or conversation-semantic validation.","fields":[{"label":"Profile","value":"openai-chat-text-2026-10-19"}],"schema":1}Formats, limits and common errors
Malformed JSON and duplicate keys reject before profile checking. Unsupported input may be valid for an API this checker does not cover.
- Profile openai-chat-text-2026-10-19: a restricted local OpenAI Chat Completions subset reviewed 19 October 2026. A valid result covers this profile only. Unsupported means outside this checker, not rejected by the provider.
- Nonempty array of at most 200 messages. Only role, content and optional name; roles developer/system/user/assistant, string content/name. Empty content is allowed.
- Multimodal content, tool/function messages, tool calls and all other fields are outside this profile. No model availability, role ordering, conversation semantics or authorization check. Input at most 65,536 bytes; standard JSON limits apply.
- Input: 65,536 UTF-8 bytes per text field. Output: at most 524,288 UTF-8 bytes; serialized responses have a separate 1 MiB ceiling. Size/work failures return no partial result.