WebSocket & SSE Mock Stream Simulator

Generate and simulate real-time event streams (financial, logs, IoT, chat) with jitter and export

12 STREAM CHUNKS

Stream Chunking & Payload

Stream Type:

Chunk Interval (ms):

Source Text / Payload to Stream:

SSE Stream Output & Handlers

data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"Next "},"finish_reason":null}]}

data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"DevUtilities "},"finish_reason":null}]}

data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"is "},"finish_reason":null}]}

data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"an "},"finish_reason":null}]}

data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"ultra-fast "},"finish_reason":null}]}

data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"developer "},"finish_reason":null}]}

data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"workstation "},"finish_reason":null}]}

data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"with "},"finish_reason":null}]}

data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"over "},"finish_reason":null}]}

data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"170 "},"finish_reason":null}]}

data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"studio "},"finish_reason":null}]}

data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"tools."},"finish_reason":"stop"}]}

data: [DONE]

// app/api/stream/route.ts
export async function GET() {
  const encoder = new TextEncoder();
  const stream = new ReadableStream({
    async start(controller) {
      const chunks = ["data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"Next \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"DevUtilities \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"is \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"an \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"ultra-fast \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"developer \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"workstation \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"with \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"over \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"170 \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"studio \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"tools.\"},\"finish_reason\":\"stop\"}]}\n\n","data: [DONE]\n\n"];
      for (const chunk of chunks) {
        controller.enqueue(encoder.encode(chunk));
        await new Promise((r) => setTimeout(r, 40));
      }
      controller.close();
    },
  });

  return new Response(stream, {
    headers: {
      'Content-Type': 'text/event-stream',
      'Cache-Control': 'no-cache, no-transform',
      Connection: 'keep-alive',
    },
  });
}

// Browser EventSource Client
const eventSource = new EventSource('/api/stream');

eventSource.onmessage = (event) => {
  if (event.data === '[DONE]') {
    return eventSource.close();
  }
  console.log('Stream chunk:', event.data);
};

data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"Next "},"finish_reason":null}]} data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"DevUtilities "},"finish_reason":null}]} data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"is "},"finish_reason":null}]} data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"an "},"finish_reason":null}]} data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"ultra-fast "},"finish_reason":null}]} data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"developer "},"finish_reason":null}]} data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"workstation "},"finish_reason":null}]} data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"with "},"finish_reason":null}]} data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"over "},"finish_reason":null}]} data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"170 "},"finish_reason":null}]} data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"studio "},"finish_reason":null}]} data: {"id":"chatcmpl-mock-123","object":"chat.completion.chunk","created":1790291449054,"choices":[{"index":0,"delta":{"content":"tools."},"finish_reason":"stop"}]} data: [DONE]

// app/api/stream/route.ts export async function GET() { const encoder = new TextEncoder(); const stream = new ReadableStream({ async start(controller) { const chunks = ["data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"Next \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"DevUtilities \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"is \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"an \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"ultra-fast \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"developer \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"workstation \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"with \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"over \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"170 \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"studio \"},\"finish_reason\":null}]}\n\n","data: {\"id\":\"chatcmpl-mock-123\",\"object\":\"chat.completion.chunk\",\"created\":1790291449054,\"choices\":[{\"index\":0,\"delta\":{\"content\":\"tools.\"},\"finish_reason\":\"stop\"}]}\n\n","data: [DONE]\n\n"]; for (const chunk of chunks) { controller.enqueue(encoder.encode(chunk)); await new Promise((r) => setTimeout(r, 40)); } controller.close(); }, }); return new Response(stream, { headers: { 'Content-Type': 'text/event-stream', 'Cache-Control': 'no-cache, no-transform', Connection: 'keep-alive', }, }); }

// Browser EventSource Client const eventSource = new EventSource('/api/stream'); eventSource.onmessage = (event) => { if (event.data === '[DONE]') { return eventSource.close(); } console.log('Stream chunk:', event.data); };