A caption overlay displays your spoken words as real-time text in your Twitch stream. Here is exactly how to set one up with StreamTranslate and OBS Browser Source.
Set Up Caption Overlay →A caption overlay for Twitch is a transparent text layer that appears on top of your stream video, displaying your spoken words as real-time text as you stream. It is the live streaming equivalent of closed captions on television — except on Twitch, there is no native caption system, so the overlay has to be added by the streamer through their streaming software.
Caption overlays work by adding the caption display as a scene element in OBS Studio (or another streaming software). The most common approach is an OBS Browser Source — a web page URL rendered as a transparent video layer within your OBS scene. StreamTranslate provides this URL, which displays your real-time captions as a transparent element positioned in the lower third of your stream.
Unlike viewer-side extensions (which require viewers to install something and are only available on Twitch), a caption overlay is burned into the video stream itself. Every viewer on every platform — Twitch, YouTube, Kick, Facebook Gaming — sees the captions as part of the video, requiring no action on their part.
OBS Studio has a source type called "Browser" that renders any web page as a transparent video layer within your scene. This is used for overlays of all kinds — donation tickers, subscriber alerts, channel graphics — and it is the mechanism StreamTranslate uses to deliver caption overlays.
StreamTranslate provides a unique URL for each account. This URL serves a web page with a transparent background that displays the current caption text, formatted and styled for streaming. OBS renders this page at 1920×160 pixels (or whatever dimensions you set) and composites it into your scene, typically in the lower third position.
The captions update in real time — StreamTranslate processes your microphone audio server-side and pushes the caption text to the browser source with sub-500ms latency, so the overlay updates within half a second of your speech.
Visit streamtranslate.live/setup and start your free trial. No credit card required. Your unique browser source URL will be generated immediately.
In the StreamTranslate dashboard, locate your browser source URL. It will look something like: https://streamtranslate.live/overlay/[your-unique-id]. Copy this URL to your clipboard.
Open OBS Studio. In the Sources panel, click the + button and select 'Browser' from the menu. Name it 'StreamTranslate Captions.' In the browser source settings, paste your URL in the URL field. Set Width to 1920 (or your stream width) and Height to 160px. Click OK.
After clicking OK, you'll see the browser source appear in your scene. Drag it to the lower third of your scene canvas — approximately 60-80px above the bottom edge. Confirm the width spans your full canvas width. The background is transparent, so only caption text will be visible.
Click Start Recording or Start Virtual Camera to preview your scene. Speak clearly into your microphone and confirm captions appear within about one second. Check that the contrast is strong (white text should be clearly visible against your game footage). Adjust positioning if captions overlap important game UI. Once satisfied, go live.
Minimum 32px at 1080p is required for accessibility. Many streamers use 38-44px for additional readability. Font weight should be Regular (400) or Semi-Bold (600) for a clean sans-serif. Avoid light weights that reduce legibility against variable game backgrounds.
White (#FFFFFF) text on a semi-transparent dark background (rgba(0,0,0,0.75)) is the accessibility standard and looks clean across all game genres. The semi-transparency keeps gameplay visible through the caption area while maintaining strong text contrast.
Lower third is standard — the same position used in TV broadcasting for captions. Leave 60-80px of margin above the absolute bottom edge for safety on TVs that crop edges. Avoid overlapping health bars, minimaps, or other critical game UI where possible.
A caption overlay is a transparent text layer added to a Twitch stream via OBS Browser Source that displays the streamer's spoken words as real-time text. It appears as part of the video and is visible to all viewers without any extensions.
OBS Browser Source renders a web page URL as a transparent video layer in your OBS scene. StreamTranslate provides a special browser source URL that shows real-time captions as this transparent layer — positioned in your lower third.
Sign up at streamtranslate.live/setup, copy your browser source URL, open OBS, add a Browser Source, paste the URL, set Width: 1920, Height: 160px, and drag to the lower third of your scene.
Caption appearance — font, size, color, background opacity — can typically be adjusted in StreamTranslate's dashboard settings. High-contrast white text on a semi-transparent dark background is the accessibility standard recommendation.
Open captions (OBS Browser Source) are burned into the video and visible to all viewers. Closed captions (StreamTranslate Twitch Extension) are viewer-controlled — each viewer toggles them on or off independently. Both can be active simultaneously for maximum coverage.