A self-hosted alternative to caption subscriptions

Hosted caption tools such as Submagic and Captions do this job well, and they ask for a subscription and your footage on their servers. OpenCaptions is the other kind of answer: open source, on your own server or your own phone.

	OpenCaptions	Hosted caption tools
Where your video goes	Stays on your server or phone	Uploaded to their service
Cost	Free to self-host; on iPhone, free with an optional one-time Pro	Usually a subscription
Account	None on iPhone; local to your instance when self-hosted	Required
The code	Open source (AGPL-3.0): read it, change it, run it	Closed
Templates	Nineteen looks and a full style panel	Usually more
Emoji, B-roll, virality scores	No	Often yes
Android	No	Often yes
Setting it up	One compose file, on hardware you look after	Nothing to run

Choose a hosted tool if you want the most templates and automation, and do not mind where the video goes.

Choose OpenCaptions if your footage should stay with you, you would rather not rent a tool you use now and then, or you want to change how it works.

Run it

You need Docker Compose and one file:

curl -O https://raw.githubusercontent.com/leogaudin/opencaptions/main/docker-compose.yml
docker compose up -d

Then open http://localhost:5173. Installation has the details, and security what to read before it is reachable by others.

Questions

Do I need a GPU? No. It runs on the CPU, and a GPU is optional.

Can I keep using a hosted speech model? Yes, if you want to: the OpenAI API with your own key is one of the choices, and the default runs on your machine.