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Overview

Every job can have its own custom data stored in the data attribute. This data is serialized to JSON and stored in Redis. 
import { Queue } from 'bullmq';

const myQueue = new Queue('paint');

const job = await myQueue.add('wall', { color: 'red' });

console.log(job.data); // { color: 'red' }

import { Queue } from 'bullmq';

const myQueue = new Queue('paint');

const job = await myQueue.add('wall', { color: 'red' });

job.data; // { color: 'red' }

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Data Structure

From src/classes/job.ts:206: 
export class Job<
  DataType = any,
  ReturnType = any,
  NameType extends string = string,
> {
  constructor(
    protected queue: MinimalQueue,
    /**
     * The name of the Job
     */
    public name: NameType,

    /**
     * The payload for this job.
     */
    public data: DataType,

    /**
     * The options object for this job.
     */
    public opts: JobsOptions = {},
    public id?: string,
  ) {
    // ...
  }
}
The data parameter accepts any type, which will be serialized to JSON when stored in Redis.

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Update Job Data

You can update a job’s data after creation using the updateData method: 
import { Job, Queue } from 'bullmq';

const queue = new Queue('paint');
const job = await Job.create(queue, 'wall', { color: 'red' });

await job.updateData({
  color: 'blue',
});

console.log(job.data); // { color: 'blue' }
From src/classes/job.ts:599: 
/**
 * Updates a job's data
 *
 * @param data - the data that will replace the current jobs data.
 */
updateData(data: DataType): Promise<void> {
  this.data = data;

  return this.scripts.updateData<DataType, ReturnType, NameType>(this, data);
}

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Data Serialization

Job data is stored as a JSON string in Redis. From src/classes/job.ts:522: 
asJSON(): JobJson {
  return removeUndefinedFields<JobJson>({
    id: this.id,
    name: this.name,
    data: JSON.stringify(typeof this.data === 'undefined' ? {} : this.data),
    // ...
  });
}
Ensure your job data is JSON-serializable. Objects with circular references, functions, or other non-serializable values will cause errors.

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Size Limits

You can set a size limit for job data to prevent extremely large payloads: 
const job = await myQueue.add(
  'wall',
  { color: 'red', image: largeImageData },
  {
    sizeLimit: 1024 * 1024, // 1MB limit
  }
);
From src/classes/job.ts:1557: 
const exceedLimit =
  this.opts.sizeLimit &&
  lengthInUtf8Bytes(jobData.data) > this.opts.sizeLimit;

if (exceedLimit) {
  throw new Error(
    `The size of job ${this.name} exceeds the limit ${this.opts.sizeLimit} bytes`,
  );
}

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Best Practices

Store only the data needed to process the job. Large payloads increase memory usage and network transfer costs.
Instead of storing large files directly, store references (URLs, S3 keys) and fetch the data during processing.
// Good
await queue.add('processImage', { imageUrl: 's3://bucket/image.jpg' });

// Avoid
await queue.add('processImage', { imageBase64: '...' }); // Large payload
Use TypeScript generics to ensure type safety:
interface PaintJobData {
  color: string;
  surface: 'wall' | 'ceiling' | 'floor';
}

const queue = new Queue<PaintJobData>('paint');

// TypeScript will catch type errors
await queue.add('wall', { color: 'red', surface: 'wall' });
From src/interfaces/base-job-options.ts:75: 
interface DefaultJobOptions {
  /**
   * Limits the size in bytes of the job's data payload (as a JSON serialized string).
   */
  sizeLimit?: number;
}

API Reference

View the Update Data API Reference

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