ChatChecker — API Chat Playground

Replay conversation JSON with your own OpenAI-compatible API. Compare replies in a chat view and keep the conversation going.

ChatChecker is your API chat playground in Chrome’s side panel. Paste a conversation, try a different model, and keep talking with the full context. REPLAY YOUR CONTEXT Paste an OpenAI messages array or a complete Chat Completions request. Parse and format JSON, inspect message roles and order, and preview the request before sending. System instructions, multimodal blocks and tool-call data are preserved. KEEP THE CONVERSATION GOING Switch to Chat view beside Parse / format for a readable conversation with chat bubbles. Each generated reply joins the history at the bottom, highlighted as NEW REPLY. Send follow-up messages with the full context. The conversation and JSON stay in sync. EDIT YOUR CONTEXT Edit or delete individual assistant, user or system messages directly in Chat view. Save applies the change to JSON and future requests; Cancel preserves the original. Structured messages have a JSON editor to preserve attachments and tool metadata. BRING YOUR OWN MODEL Configure your own Base URL, API key and model ID. Save multiple connections. A short API test validates each connection before saving, with progress and errors shown below the button. Use any provider supporting OpenAI Chat Completions. INSPECT EVERY RESPONSE View response time, token usage, finish reason, request parameters and raw response JSON. Copy responses, stop requests, or retry a failed turn without duplicating your message. The first returned choice joins the conversation; all choices remain in the response. Tool calls are displayed but never executed. LOCAL BY DESIGN Connections are stored on your device without Chrome Sync. Keys are saved only if you select Remember key locally; that local storage is not encrypted. Conversations and generated replies stay in panel memory. Optional page imports use temporary browser session storage. No developer relay server, ads, analytics or telemetry. Requests go directly to your chosen API endpoint only when you validate or generate. Your provider’s privacy policy applies. GET STARTED 1. Open ChatChecker from the toolbar. 2. Enter your provider’s Base URL (including its required /v1 prefix), API key and exact model ID, then validate. 3. Paste conversation JSON or load the example. 4. Open Chat view, generate a reply, and send your next message. Chrome 116+ required. Bring your own API account and quota; provider charges may apply. Supports non-streaming OpenAI Chat Completions requests.