Top 10 Data Annotation Tools for NLP and Speech Recognition

Top 10 Data Annotation Tools for NLP and Speech Recognition: A Comprehensive Review

With the rise in need for data annotation, it is imperative to be informed on what data annotation tools are available to you. Data annotation is a crucial step in training machine learning models, particularly for natural language processing (NLP) and speech recognition technology (SRT) applications. Manual annotation of large datasets can be time-consuming and error-prone, making it essential to leverage data annotation tools that streamline the process. In this blog post, we will review the top 10 data annotation tools for NLP and SRT, examining their features, ease of use, and pricing models.


Labelbox is a versatile data annotation tool that supports NLP and SRT projects. Its user-friendly interface allows annotators to label text, audio, and video data efficiently. Labelbox offers a variety of annotation types, including classification, named entity recognition, sentiment analysis, and speech transcription. Its collaborative features facilitate team collaboration and version control. Labelbox’s pricing model is based on a subscription plan, with different tiers depending on usage and team size.




Prodigy, developed by Explosion AI, is a powerful annotation tool specifically designed for NLP tasks. It offers a range of annotation workflows, such as named entity recognition, text classification, and relation extraction. Prodigy’s active learning capabilities help reduce annotation efforts by selecting the most informative examples for annotation. It provides an intuitive web-based interface and supports integration with popular NLP frameworks like spaCy. Prodigy follows a per-user licensing model, making it suitable for individual practitioners and small teams.


Hasty is a cloud-based annotation platform with extensive support for NLP and SRT projects. It offers a collaborative environment, enabling teams to work together on complex annotation tasks. Hasty supports annotation types like text classification, named entity recognition, and speech transcription. The platform includes a robust quality control system with annotation review and adjudication features. Hasty’s pricing is based on a pay-as-you-go model, making it flexible for projects of all sizes.


Figure Eight

Figure Eight, recently acquired by Appen, is a popular data annotation tool that caters to various machine learning domains, including NLP and SRT. It supports annotation tasks like text classification, entity extraction, sentiment analysis, and audio transcription. Figure Eight’s platform offers flexible customisation options and integration capabilities, allowing users to adapt the tool to their specific needs. Pricing is based on a usage-based model, with costs determined by task complexity and volume.



Tagtog is a collaborative annotation platform primarily focused on NLP projects. It supports a wide range of annotation tasks, such as named entity recognition, coreference resolution, and relation extraction. Tagtog offers an intuitive interface with features like entity linking, customisable annotation schemas, and real-time collaboration. It provides both free and premium plans, making it suitable for individual researchers and small teams.



Snorkel is a unique data annotation tool that combines machine learning with human supervision. It allows users to create training data programmatically by writing labeling functions, which are then used to train a generative model. Snorkel supports various NLP tasks like text classification, sequence tagging, and relation extraction. Its active learning features aid in reducing manual annotation efforts. Snorkel is an open-source tool, making it cost-effective for research and development projects.


LightTag is a versatile annotation platform suitable for NLP and SRT projects. It offers annotation types like text classification, entity recognition, and sentiment analysis. LightTag provides an intuitive interface with efficient collaboration features and customisable workflows. It supports multiple annotation guidelines, enabling users to handle complex annotation tasks. LightTag’s pricing is based on a subscription model, with different plans depending on usage and team size.


Amazon SageMaker Ground Truth

Amazon SageMaker Ground Truth is a fully managed data labeling service by Amazon Web Services (AWS). It supports a wide range of annotation tasks for NLP and SRT, including text classification, named entity recognition, and speech transcription. Ground Truth combines automatic annotation with human review to improve efficiency. It offers integration with other AWS services and provides comprehensive quality control mechanisms. Pricing for SageMaker Ground Truth is usage-based, with costs varying depending on the annotation task complexity and volume.



Datumbox is a cloud-based data annotation platform with a focus on NLP and text analytics. It provides annotation support for tasks such as sentiment analysis, text categorisation, and document classification. Datumbox offers an easy-to-use interface and allows customisation of annotation schemas. It provides a RESTful API, enabling seamless integration with other applications. Pricing for Datumbox is based on a pay-as-you-go model, making it suitable for projects of different scales.



Appen, a leading provider of human-annotated training data, offers a comprehensive suite of data annotation services. With expertise in NLP and SRT, Appen provides high-quality annotation solutions for tasks like text classification, named entity recognition, and audio transcription. Appen’s strength lies in its global crowd of skilled annotators, ensuring diverse language support and high accuracy. Pricing for Appen’s services varies based on project requirements and is typically negotiated on a case-by-case basis.

Selecting the right data annotation tool is crucial for NLP and SRT projects, as it directly impacts the quality and efficiency of machine learning models. The reviewed top 10 data annotation tools offer a wide range of features, ease of use, and pricing models to cater to diverse project needs. From Labelbox’s versatility to Prodigy’s active learning capabilities and Hasty’s collaboration features, there is a tool for every requirement and budget. Whether you choose a commercial tool like Figure Eight or opt for open-source options like Snorkel, these tools provide valuable support for accurate and scalable data annotation. Evaluate your project requirements, consider the available features, and select the tool that aligns best with your needs to accelerate your NLP and SRT machine learning endeavours.


With a 21-year track record of excellence, we are considered a trusted partner by many blue-chip companies across a wide range of industries. At this stage of your business, it may be worth your while to invest in a human transcription service that has a Way With Words.

Additional Services

Video Captioning Services
About Captioning

Perfectly synched 99%+ accurate closed captions for broadcast-quality video.

Machine Transcription Polishing
Machine Transcription Polishing

For users of machine transcription that require polished machine transcripts.

Speech Collection for AI training
About Speech Collection

For users that require machine learning language data.