Vircadia
Second Life
VRChat
Facebook Spaces
Hubs by Mozilla
OpenSimulator
Sansar
vTime XR
RepDB
RepDB is a one-time-purchase exercise dataset for developers building fitness and workout apps โ not a subscription, not a rate-limited API. You download the data once and own it: JSON (and SQLite on the higher tier), WebP images, and full EN/DE/ES translations, with no per-request billing and no dependency on our servers staying up.
A free tier includes 250 exercises with flat-style 512ร512 images, attribution-licensed for commercial in-app use. The Starter tier ($199) adds the full catalog in classic white-background style. Standard ($399) adds transparent 1024px images, looping animations, exercise relations (similar/progressions/regressions), workout templates, and embeddings โ exclusive to that tier.
Every exercise includes muscle-group highlighting, equipment/muscle icons, MET values, and safety/goal tags. Compared to GIF- or JPG-based competitor APIs, RepDB images are transparent WebP with no watermarks, so they drop into any app UI without a white box around them.
Vircadia RepDBRepDB's answer:
RepDB is sold as a one-time download, not a metered API โ you own the JSON/SQLite data and WebP images outright, with no rate limits, no per-request billing, and no risk of the vendor cutting off access. It's also the only dataset in this space with EN/DE/ES translations, transparent (alpha-channel) images with no watermark, muscle-group highlighting, safety/goal tags, and looping animations on the higher tier.
RepDB's answer:
RepDB grew out of a consumer workout app its creator was building solo. Sourcing exercise images and data meant either paying for a subscription API with usage caps and no caching rights, or producing everything from scratch. The illustrated, multi-language dataset was built for us first, then split out as its own product once it became clear other indie developers had the same problem and preferred to buy the data outright rather than rent it through an API.
RepDB's answer:
Most alternatives are subscription APIs โ you pay monthly, you're capped on requests, and ExerciseDB's terms of use explicitly forbid caching or storing the data at all, so every image render is a live paid API call. RepDB is the opposite: pay once, download the files, self-host with zero ongoing dependency. It's also the only option offering true DE/ES localization and transparent images instead of a white box behind every exercise.
RepDB's answer:
Solo developers and small teams building fitness or workout-tracking apps (iOS, Android, web) who need licensed exercise images and structured exercise data, but don't want to build their own media pipeline or depend on a rate-limited third-party API.
Most of the 3D world experiences limit what a user can build and do. This is not so with Vircadia. The Apache license makes this 3D application the most flexible tool for building custom and interactive worlds. Vircadia is truly free, open and relatively easy to use. There are several developers who are working and improving this platform daily! Free content ensures that new users have access to materials for building their world without having to worry about learning difficult 3D applications. I highly recommend Vircadia and believe this will be the next big server technology on the world wide web.
Probably the best open-source metaverse
Based on our record, Vircadia seems to be more popular. It has been mentiond 19 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Vircadia is an open source (Apache 2.0) metaverse ecosystem consisting of a high performance real-time server architecture (C++), web SDK (TS), and web client (TS). Source: over 2 years ago
Not pre-baked. I work on https://vircadia.com/ -- it has to give every user their own audio mix to account for their 3D position. This means codec costs add up fast. You can't just encode once and stream the same thing to a dozen people. - Source: Hacker News / over 4 years ago
Both, primarily the first. Low latency is definitely a requirement, but no issues with Opus on that account. > I haven't looked into how expensive it is to encode in terms of CPU time, so I assume maybe you're taking about a bottleneck in terms of the number of simultaneous streams you can support on a single CPU? Yup! I work on https://vircadia.com/ -- we have to compress audio in real time and every user gets... - Source: Hacker News / over 4 years ago
Second Life improved avatars by quite a lot in fairly recent times. There's also alternatives to it, eg, check out the project I work on: https://vircadia.com/ It's a sort of spiritual successor to Second Life, since it was started by the same guy -- Philip Rosedale -- after he left SL. It didn't quite work, so the commercial project died and got picked up by open source forks, which is what I work on. It's less... - Source: Hacker News / over 4 years ago
To me it's useful/entertaining in the ways forums and chats are, plus some additional features on top of that. Eg, you can talk to people, but in addition to that you have a collaborative 3D environment with positional audio where you can script, make games or do other stuff. Recently a group using our project put up a Christmas Carol VR play, and the results were most impressive. https://vircadia.com/ -- it's an... - Source: Hacker News / over 4 years ago
Second Life - Second Life is a virtual reality platform where individuals interact in a virtual world. The software was developed in 2003 by Linden Labs. More than one million people now regularly use the software.
VRChat - Create and play in virtual worlds with others
Facebook Spaces - Facebook's social Virtual Reality platform is here!
Hubs by Mozilla - A WebVR experiment from Mozilla Mixed Reality
OpenSimulator - OpenSimulator is an open source multi-platform, multi-user 3D application server.
Sansar - Shop and browse The Sansar Store, the official marketplace for the internet's leading social VR platform. Buy or sell items for your avatars, virtual reality worlds, and more.
