Use Queues to store data in R2

Example of how to use Queues to batch data and store it in an R2 bucket.

Last updated Apr 21, 2026 The following Worker will catch JavaScript errors and send them to a queue. The same Worker will receive those errors in batches and store them to a log file in an R2 bucket.

{
    "$schema": "./node_modules/wrangler/config-schema.json",
    "name": "my-worker",
    "queues": {
        "producers": [
            {
                "queue": "my-queue",
                "binding": "ERROR_QUEUE"
            }
        ],
        "consumers": [
            {
                "queue": "my-queue",
                "max_batch_size": 100,
                "max_batch_timeout": 30
            }
        ]
    },
    "r2_buckets": [
        {
            "bucket_name": "my-bucket",
            "binding": "ERROR_BUCKET"
        }
    ]
}

"$schema" = "./node_modules/wrangler/config-schema.json"
name = "my-worker"

[[queues.producers]]
queue = "my-queue"
binding = "ERROR_QUEUE"

[[queues.consumers]]
queue = "my-queue"
max_batch_size = 100
max_batch_timeout = 30

[[r2_buckets]]
bucket_name = "my-bucket"
binding = "ERROR_BUCKET"

interface ErrorMessage {
    message: string;
    stack?: string;
}

interface Env {
    readonly ERROR_QUEUE: Queue<ErrorMessage>;
    readonly ERROR_BUCKET: R2Bucket;
}

export default {
  async fetch(req, env, ctx): Promise<Response> {
    try {
      return doRequest(req);
    } catch (e) {
      const error: ErrorMessage = {
        message: e instanceof Error ? e.message : String(e),
        stack: e instanceof Error ? e.stack : undefined,
      };
      await env.ERROR_QUEUE.send(error);
      return new Response(error.message, { status: 500 });
    }
  },
  async queue(batch, env, ctx): Promise<void> {
    let file = "";
    for (const message of batch.messages) {
      const error = message.body;
      file += error.stack ?? error.message;
      file += "\r\n";
    }
    await env.ERROR_BUCKET.put(`errors/${Date.now()}.log`, file);
  },
} satisfies ExportedHandler<Env, ErrorMessage>;

function doRequest(request: Request): Response {
  if (Math.random() > 0.5) {
    return new Response("Success!");
  }
  throw new Error("Failed!");
}

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description: Use the dashboard to send messages to a queue. title: Send messages from the dashboard image: https://developers.cloudflare.com/queues/examples/send-messages-from-dash/og.png?v=8c26d59077a88065

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