Line 21

Line 21's AI Proofreader is a specialized tool that checks and corrects live captions as they are created. It works within the broader Line 21 captioning platform to fix grammar, spelling, punctuation, and contextual errors in real-time. This is designed for live events where accuracy is critical, such as keynotes, panels, and broadcasts. The tool integrates directly into the captioner's workflow, offering suggestions or making automatic edits before text reaches the audience.

The system is built on large language models, including options like GPT-5 and Claude 3.7 Sonnet. What makes it stand out is its high degree of configurability. Users can set custom rules for spelling preferences and industry terminology. They also choose from three 'trust modes': Advisor for suggestions only, Assistant for live edits with an undo option, and Approver for fully automated final checks. You can also toggle between 'Speed' and 'Accuracy' precision levels, depending on whether you need quick fixes or deeper, context-aware revisions.

This tool is most useful for organizations that run live, captioned events and need a reliable safety net for human captioners. Event producers, universities hosting lectures, and corporations streaming all-hands meetings benefit from the added layer of accuracy. It helps ensure that accessibility commitments are met with higher quality text, reducing the risk of embarrassing or confusing errors being broadcast to viewers.