# Runway details how Characters hits a 1.75s response time

By Steven Van · 2026-05-05

A technical breakdown of the real-time conversational video agent, built on GWM-1, now live via the Runway API and apps.

[Runway](<https://creatorstoolbox.com/tools/runway>) published a technical breakdown of Runway Characters, a real-time conversational video agent that turns a single reference image, photorealistic, cartoon or fantasy, into an expressive character with no fine-tuning required. Built on Runway's GWM-1 world model, it generates natural lip-sync, facial expressions and head motion at 24fps in HD.

The system runs at an effective **37 milliseconds** of model time per frame and a **1.75 second** server-side turn-around from when a user stops speaking to when the character starts responding. Runway credits this to autoregressive frame-by-frame generation, with the diffusion transformer and VAE decoder running concurrently so decode time mostly disappears from the critical path, plus parallelization across devices, KV-cache management, CUDA Graphs and tuned kernels.

Alongside the model, Runway built out a product surface for deploying characters:

- **Vision**: characters can see a user's webcam or shared screen during a session.

- **Custom Voice**: text-to-voice design from a prompt, or instant voice cloning from an audio sample.

- **Tool Calling**: characters can trigger defined UI actions or backend calls during a conversation.

- **Knowledge base**: text and Markdown documents can be attached so a character answers from a company's own material.

- **Embeddable widget**: a real-time character can be dropped into a web app with one line of code.

- **Meeting integration**: characters can join Zoom, Google Meet or Teams calls and respond in real time.

Runway Characters is [available now](<https://runwayml.com/news/building-runway-characters>) via the Runway API and the Runway web and mobile apps.

[![](<https://d3phaj0sisr2ct.cloudfront.net/site/images/news/Character-blog-og-compressed.jpg>)](<https://runwayml.com/news/building-runway-characters>)

![Runway](<https://www.google.com/s2/favicons?domain=runwayml.com&sz=128>)

Runway

AI-powered creative suite for generating and editing video, images, and 3D — featuring the world's most advanced video generation model.

[View Runway →](<https://creatorstoolbox.com/tools/runway>)

[Original source](<https://runwayml.com/news/building-runway-characters>)

[Read Runway details how Characters hits a 1.75s response time on Creators Toolbox](<https://creatorstoolbox.com/blog/runway-how-we-built-runway-characters>)

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Canonical source: https://creatorstoolbox.com/blog/runway-how-we-built-runway-characters