Free Chat messages JSON builder
Generate OpenAI-style chat bodies for docs, tests, and prototypes — you still bring the API key.
How to use this tool
- 1
Open LLM messages JSON
Use it for this task: OpenAI-style chat messages JSON, system / user / assistant roles, vision content[] examples - in-browser.
- 2
Paste or upload the source content
Put the original text or file in the input area, then choose the conversion or formatting options.
- 3
Copy or download the converted result
Check the preview first, then copy the output or download the generated file.
Quick facts
| Runs offline? | Yes — after load, processing stays in your browser. |
|---|---|
| Uploads data? | No. Your input is not sent to our servers. |
| Account required? | No signup or login. |
| Locales? | UI in 7 languages; tool logic is locale-agnostic. |
Top use cases
- OpenAI-style chat messages JSON, system / user / assistant roles, vision content[] examples - in-browser.
- Runs offline?: Yes — after load, processing stays in your browser.
- Uploads data?: No. Your input is not sent to our servers.
- Account required?: No signup or login.
- Locales?: UI in 7 languages; tool logic is locale-agnostic.
FAQ
Does my data leave this device?▾
No. JSON is assembled locally; nothing is posted to OpenAI from this page.
Is this an official OpenAI product?▾
No. Safe Local Tools only helps you draft request-shaped JSON — verify against current API docs.
Why are empty messages removed?▾
Blank assistant/user lines are filtered so the payload stays valid and small.
Does it sign requests or add headers?▾
No — copy the JSON into your client, curl, or tests and add auth yourself.
What about tool calls or system tools?▾
Not handled here — extend the JSON manually when you need tools, JSON mode, or streaming options.
How to report issues?▾
Use the Contact link in the site footer.