MTurk too complicated? Try BOLT

Get next-day annotations on the BOLT labeling platform. Our plugged-in workforce scales up or down easily with no minimum commitment.


Set up a project in less than 10 minutes

Trained annotators

Visualize labeled images

Annotation analytics

QA tools

Cost certainty

Get all the benefits of an in-house team without using any internal resources

Fast proof-of-concept (POC)

Start a project on BOLT and get annotations back in a day. Upload data, set up labels and instructions, and images will be annotated by our plugged-in workforce.

Scale up and down anytime

Pay as you go, with no minimum fees. Start a project without a credit card. Only pay when you've used up your $50 free credit on us. View our fees here

Trained annotators you can trust

Hand-picked trained annotators to give you feedback on your dataset. Give feedback to annotators to improve your annotations for the next iteration.

Why choose BOLT?

Let us label the data so you can train your model faster

Real-time output visibility

View progress, annotated images, label distribution in real-time

Iterate with insights

Review your labeled data and send bad annotations back for relabeling

Set up with ease

Upload your data, set up labels and instructions – and you're good to go

Team collaboration

Invite your team members to review and export annotations

Fast iteration

Spin up multiple projects at the same time, get next-day annotations

Dedicated support

In-app chat support, email and call support to get you going.

Why our users love BOLT

“The annotators were really quick. I would upload and 5 minutes later - 10 images done. I checked 5 minutes later - 100 images done.”

Sparsh Shankar
Associate Machine Learning Engineer at Sprinklr

“The best interface for self-service labeling. Everything from uploading data to seeing it labeled in real time was really cool. This is just way simpler to use compared to Amazon Sagemaker and LabelBox.

Jonas Olausson
Data Engineer at

Got a question?

Read our FAQs or explore our Documentation to learn more.
Is BOLT better than AWS MTurk?
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Glad you asked! Send us a test batch of data. We’ll run the project and add you as a collaborator for you to view the results. Send us a test batch of data to get started.

Who will label my data?
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Our trained annotators will label your data (after undergoing a stringent series of training courses and assessments, of course). They are remote annotators who work part-time on different projects available via our platform. Annotators are assigned to projects automatically once they are qualified for the tasks.

What output formats are supported?
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Currently, we only support COCO JSON output format. We'll be introducing other output formats soon. If you require another output format, drop us a message here.

How quickly can I expect to receive annotated images?
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Our annotators will start labeling your data as soon as you start a project. One of our users received annotated images with around 2,500 annotations in less than 2 hours. Note: turnaround time varies according to the complexity of the project.

How do I manage labeling quality on BOLT?
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Before you start, provide clear labeling instructions so our annotators understand how to label your images accurately. Our annotators will also help you surface label noise through our built-in collaborative feedback loop.

Who has access to my data?
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Your data is only visible to human labelers throughout the labeling process. We will not share or use your data for any reason other than the labeling.