When you're producing one of Europe's largest technology events, accessibility can't be an afterthought.
London Tech Week brings together thousands of innovators, entrepreneurs, investors, and global technology leaders for three days of keynote presentations, product launches, and technical discussions. Every session is an opportunity to inspire, but only if every attendee can fully engage with the content.
Following a successful captioning pilot in 2025, event organizers expanded live captioning across the event for 2026, increasing coverage from the main stage to five additional exhibition stages. For Mantis, the production partner responsible for delivering the experience, the challenge wasn't simply generating captions, it was ensuring they were accurate, visually polished, and seamlessly integrated into the event production.
Scaling Accessibility Across Multiple Stages
The expanded deployment meant managing six simultaneous caption feeds across stages ranging from keynote presentations to breakout sessions.
Unlike traditional broadcast workflows, several of the exhibition stages weren't being streamed publicly. Instead, Mantis transmitted audio-only feeds into SyncWords while centrally monitoring every caption service from a single location. By routing each stage through a dedicated workflow with clear stage identifiers, the production team could instantly verify that the correct captions were being delivered to the correct display.
This streamlined approach allowed operators to confidently manage multiple live stages without adding unnecessary complexity.
More Than Captions - A Branded Experience
For London Tech Week, accessibility needed to feel like part of the production, not an overlay added at the last minute.
One of the capabilities that made this possible was SyncWordsâ Caption Widget. Rather than providing a fixed caption display, the widget allows developers and production teams to fully customize its appearance using standard CSS.
That flexibility enabled Mantis to tailor the caption experience to match London Tech Week's branding without building a custom application. Fonts, colors, backgrounds, sponsor graphics, and caption positioning were all customized to complement the event's visual identity.
The CSS customization also solved practical production challenges.
The main stage utilized an advanced vision mixer capable of creating sophisticated layouts, while the exhibition stages relied on simpler switchers that could only overlay content. By adjusting the widget's layout and positioning through CSS, Mantis created caption experiences that worked beautifully regardless of the production equipment being used.
Lessons learned from the previous year's event also drove improvements. During session breaks, captions occasionally remained visible after presenters had finished speaking. Using the widget's customizable styling and timing behavior, Mantis configured captions to automatically fade away after a short period of inactivity, creating a cleaner and more polished transition between sessions.
These small refinements helped ensure the accessibility experience looked intentional rather than improvised.
Preparation Makes the Difference
Successful live captioning begins long before the first presenter steps on stage.
Working together before the event, Mantis and SyncWords reviewed speaker names, company names, technical terminology, and industry-specific vocabulary to optimize recognition accuracy.
Rather than overwhelming the speech recognition engine with thousands of unnecessary entries, the team built a carefully curated custom dictionary containing approximately 100 to 150 specialized names and terms that were most likely to benefit from additional guidance.
This targeted approach allowed the AI to recognize unique terminology while relying on its existing language model for common technology terms.
The result was a workflow that balanced preparation with the intelligence of modern speech recognition.
Fine-Tuning for Live Performance
For live events, every second matters.
Through extensive testing before London Tech Week, Mantis optimized its workflow and reduced end-to-end caption latency from approximately five seconds to around three and a half seconds.
That improvement may sound modest on paper, but during live presentations it creates a noticeably more natural viewing experience.
As Steve from Mantis explained:
"I think people would point [the 5 second latency] out. I was excited when I got it down to three and a half seconds."
The team also leveraged the SyncWords API and enhanced monitoring to automate parts of the workflow and provide additional confidence that every caption stream was operating correctly throughout the event.
âThe Results
The expanded deployment successfully delivered live captions across the main stage and five exhibition stages, making technical presentations more accessible for attendees throughout London Tech Week.
For Mantis, centralized monitoring, flexible customization, and reliable caption delivery simplified production across multiple venues.
For London Tech Week, accessibility became an integrated part of the event experience while maintaining the premium visual standards expected from one of the world's leading technology events.
Perhaps the strongest endorsement came after the event itself.
According to Steve from Mantis:
"Key client and audience members told us it's the best captions they've ever seen."
For both Mantis and SyncWords, that feedback reinforced an important lesson.
Outstanding live captioning isn't achieved through AI alone. It comes from thoughtful planning, close collaboration, careful implementation, and the flexibility to adapt the technology to each event's unique production requirements.
While AI delivers the words, the presentation matters just as much. By combining accurate speech recognition with a fully customizable caption experience, Mantis was able to create an accessibility solution that didn't simply meet compliance requirements, it enhanced the overall production.
As more organizations look to make live events accessible without compromising production quality, London Tech Week demonstrates what's possible when experienced production teams are equipped with tools designed to fit seamlessly into professional workflows.
