{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,23]],"date-time":"2026-01-23T09:14:17Z","timestamp":1769159657509,"version":"3.49.0"},"reference-count":47,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2024,4,8]],"date-time":"2024-04-08T00:00:00Z","timestamp":1712534400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Virtual Worlds"],"abstract":"<jats:p>One of the most critical challenges for the success of the Metaverse is interoperability amongst its virtual platforms and worlds. In this context, application programming interfaces (APIs) are essential. This study analyzes a sample of 15 Metaverse platforms. In the first step, the availability of publicly accessible APIs was examined. For those platforms offering an API, i.e., Decentraland, Second Life, Voxels, Roblox, Axie Infinity, Upland, and VRChat, the available API contents were collected, analyzed, and presented in the paper. The results show that only a few Metaverse platforms offer APIs at all. In addition, the available APIs are very diverse and heterogeneous. Information is somewhat fragmented, requiring access to several APIs to compile a comprehensive data set. Thus, standardized APIs will enable better interoperability and foster a more seamless and immersive user experience in the Metaverse.<\/jats:p>","DOI":"10.3390\/virtualworlds3020008","type":"journal-article","created":{"date-parts":[[2024,4,9]],"date-time":"2024-04-09T02:52:17Z","timestamp":1712631137000},"page":"157-170","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["APIs in the Metaverse\u2014A Systematic Evaluation"],"prefix":"10.3390","volume":"3","author":[{"given":"Marius","family":"Traub","sequence":"first","affiliation":[{"name":"Faculty of Electronics and Computer Science, Aalen University of Applied Science, 73430 Aalen, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7128-669X","authenticated-orcid":false,"given":"Markus","family":"Weinberger","sequence":"additional","affiliation":[{"name":"Faculty of Electronics and Computer Science, Aalen University of Applied Science, 73430 Aalen, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2024,4,8]]},"reference":[{"key":"ref_1","unstructured":"Buchholz, K. (2024, January 30). How the Metaverse Is Making Money. Available online: https:\/\/www.statista.com\/chart\/29329\/metaverse-revenue\/."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Weinberger, M. (2022). What Is Metaverse?\u2014A Definition Based on Qualitative Meta-Synthesis. Future Internet, 14.","DOI":"10.3390\/fi14110310"},{"key":"ref_3","unstructured":"Knight, W. (2024, January 24). BMW\u2019s Virtual Factory Uses AI to Hone the Assembly Line: The German Automaker Uses New Software from Chipmaker Nvidia to Simulate Train Robots and Human Workers. Available online: https:\/\/www.wired.com\/story\/bmw-virtual-factory-ai-hone-assembly-line\/."},{"key":"ref_4","unstructured":"Avietra, S.r.l. (2024, January 24). Cabin Crew Training. Available online: https:\/\/www.avietra.com\/cabincrew.html."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"486","DOI":"10.3390\/encyclopedia2010031","article-title":"Metaverse","volume":"2","author":"Mystakidis","year":"2022","journal-title":"Encyclopedia"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Zaman, S., Dantu, R., Badruddoja, S., Talapuru, S., and Upadhyay, K. (2023, January 26\u201328). Layerwise Interoperability in Metaverse: Key to Next-Generation Electronic Commerce. Proceedings of the 2023 IEEE International Conference on Metaverse Computing, Networking and Applications (MetaCom), Kyoto, Japan.","DOI":"10.1109\/MetaCom57706.2023.00018"},{"key":"ref_7","unstructured":"Lee, L.-H., Braud, T., Zhou, P., Wang, L., Xu, D., Lin, Z., Kumar, A., Bermejo, C., and Hui, P. (2021). All One Needs to Know about Metaverse: A Complete Survey on Technological Singularity, Virtual Ecosystem, and Research Agenda. arXiv."},{"key":"ref_8","unstructured":"Ball, M. (2022). The Metaverse: And How It Will Revolutionize Everything, Liveright Publishing Corporation, a Division of W.W. Norton & Company. [1st ed.]."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Karaarslan, E., Aydin, \u00d6., Cali, \u00dc., and Challenger, M. (2023). Digital Twin Driven Intelligent Systems and Emerging Metaverse, Springer Nature Singapore. [1st ed.].","DOI":"10.1007\/978-981-99-0252-1"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"e4658","DOI":"10.1002\/ett.4658","article-title":"Blockchain-based asset storage and service mechanism to metaverse universe: Metarepo","volume":"34","author":"Ersoy","year":"2022","journal-title":"Trans. Emerg. Telecommun. Technol."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Yu, B., Liu, Y., Ren, S., Zhou, Z., and Liu, J. (2023). METAseen: Analyzing network traffic and privacy policies in Web 3.0 based Metaverse. Digit. Commun. Netw., in press.","DOI":"10.1016\/j.dcan.2023.11.006"},{"key":"ref_12","unstructured":"Biehl, M. (2015). API Architecture, API-University Press."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"105314","DOI":"10.1016\/j.clsr.2019.03.008","article-title":"Data sharing and interoperability: Fostering innovation and competition through APIs","volume":"35","author":"Borgogno","year":"2019","journal-title":"Comput. Law Secur. Rev."},{"key":"ref_14","unstructured":"IBM (2023, July 28). Was Ist Eine REST-API?. Available online: https:\/\/www.ibm.com\/de-de\/topics\/rest-apis."},{"key":"ref_15","unstructured":"AWS (2023, July 28). What is RESTful API?-RESTful API Explained-AWS. Available online: https:\/\/aws.amazon.com\/what-is\/restful-api\/."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Brito, G., and Valente, M.T. (2020, January 16\u201320). REST vs GraphQL: A Controlled Experiment. Proceedings of the 2020 IEEE International Conference on Software Architecture (ICSA), Salvador, Brazil.","DOI":"10.1109\/ICSA47634.2020.00016"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Botto-Tobar, M., Zambrano Vizuete, M., Torres-Carri\u00f3n, P., Montes Le\u00f3n, S.R., Pizarro V\u00e1squez, G., and Durakovic, B. (2020). Applied Technologies: First International Conference ICAT 2019 Quito Ecuador 3\u20135 December 2019 Proceedings Part I, Springer International Publishing. [1st ed.].","DOI":"10.1007\/978-3-030-42517-3"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Braubach, L., Murillo, J.M., Kaviani, N., Lama, M., Burgue\u00f1o, L., Moha, N., and Oriol, M. (2018). Service-Oriented Computing\u2013ICSOC 2017 Workshops: ASOCA ISyCC WESOACS and Satellite Events M\u00e1laga Spain 13\u201316 November 2017 Revised Selected Papers, Springer International Publishing.","DOI":"10.1007\/978-3-319-91764-1"},{"key":"ref_19","unstructured":"GraphQL (2023, July 28). GraphQL\u2014A Query Language for Your API. Available online: https:\/\/graphql.org\/."},{"key":"ref_20","unstructured":"Spasev, V., Dimitrovski, I., and Kitanovski, I. (2024, April 04). An Overview of GraphQL: Core Features and Architecture. Available online: https:\/\/repository.ukim.mk\/bitstream\/20.500.12188\/19669\/1\/ICT_2020_submission_40.pdf."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"297","DOI":"10.14257\/ijdta.2015.8.3.26","article-title":"A Comparative Investigation on Implementation of RESTful versus SOAP based Web Services","volume":"8","author":"Bora","year":"2015","journal-title":"Int. J. Database Theory Appl."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Seabra, M., Naz\u00e1rio, M.F., and Pinto, G. (2019, January 23\u201324). REST or GraphQL?: A Performance Comparative Study. Proceedings of the XIII Brazilian Symposium on Software Components, Architectures, and Reuse, Salvador, Brazil.","DOI":"10.1145\/3357141.3357149"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"537","DOI":"10.52953\/REVF5378","article-title":"A comparison of virtual worlds based on the metaverse maturity model","volume":"4","author":"Weinberger","year":"2023","journal-title":"ITU J. Futur. Evol. Technol."},{"key":"ref_24","unstructured":"Epic Games, and People Can Fly (2017). Fortnite, Gearbox Publishing."},{"key":"ref_25","unstructured":"Minecraft (2024, January 29). What Is Minecraft?. Available online: https:\/\/www.minecraft.net\/en-us\/about-minecraft."},{"key":"ref_26","unstructured":"Axie Infinity-Battle, Collect, and Trade Collectible NFT Creatures (2023, November 20). Axie Infinity-Battle, Collect, and Trade Collectible NFT Creatures. Available online: https:\/\/axieinfinity.com\/."},{"key":"ref_27","unstructured":"Decentraland (2023, July 05). Welcome to Decentraland. Available online: https:\/\/decentraland.org\/."},{"key":"ref_28","unstructured":"Roblox Corporation (2023, November 20). Roblox. Available online: https:\/\/www.roblox.com\/."},{"key":"ref_29","unstructured":"Second Life (2023, July 18). Offizielle Seite Second Life-Virtuelle Welten, Virtuelle Realit\u00e4t, VR, Avatare und Kostenloser 3D-Chat. Available online: https:\/\/secondlife.com\/."},{"key":"ref_30","unstructured":"Upland (2023, November 20). Rebuild the World. Available online: https:\/\/www.upland.me\/."},{"key":"ref_31","unstructured":"Nolan Consulting Limited (2023, November 20). Voxels Homepage. Available online: https:\/\/www.voxels.com\/."},{"key":"ref_32","unstructured":"VRChat Inc (2024, January 25). VR-Chat Website. Available online: https:\/\/hello.vrchat.com\/."},{"key":"ref_33","unstructured":"Decentraland (2023, December 05). LAND API Reference. Available online: https:\/\/docs.decentraland.org\/player\/market\/api\/."},{"key":"ref_34","unstructured":"OpenSea: Metadata Standards (2024, April 04). How to Add Rich Metadata to Your ERC721 or ERC1155 NFTs. Available online: https:\/\/docs.opensea.io\/docs\/metadata-standards."},{"key":"ref_35","unstructured":"(2023, December 05). Decentraland. Available online: https:\/\/events.decentraland.org\/docs\/."},{"key":"ref_36","unstructured":"Second Life Wiki (2023, December 05). APIs and Web Services Portal. Available online: https:\/\/wiki.secondlife.com\/wiki\/APIs_and_Web_Services_Portal."},{"key":"ref_37","unstructured":"Second Life Wiki (2023, December 05). Search API. Available online: https:\/\/wiki.secondlife.com\/wiki\/Search_API."},{"key":"ref_38","unstructured":"Voxels Wiki (2023, December 05). Voxels External APIs. Available online: https:\/\/wiki.cryptovoxels.com\/en\/External-API."},{"key":"ref_39","unstructured":"Developer Forum|Roblox (2023, December 05). All of Roblox\u2019s APIs. Available online: https:\/\/devforum.roblox.com\/t\/all-of-robloxs-apis\/2290645."},{"key":"ref_40","unstructured":"Sky Mavis Developer Documentation (2023, December 05). Origins API. Available online: https:\/\/docs.skymavis.com\/api\/origins\/."},{"key":"ref_41","unstructured":"Upland (2023, December 05). Upland Developers API. Available online: https:\/\/api.sandbox.upland.me\/developers-api\/docs\/."},{"key":"ref_42","unstructured":"VRChat Community (2024, January 25). VRChat API Documentation. Available online: https:\/\/vrchat.vercel.app\/#\/."},{"key":"ref_43","unstructured":"OpenSea (2023, December 05). OpenSea, der Gr\u00f6\u00dfte NFT-Marktplatz. Available online: https:\/\/opensea.io\/de-DE."},{"key":"ref_44","unstructured":"Kayyali, A. (2024, January 29). How Many Metaverses Are There?. Available online: https:\/\/insidetelecom.com\/how-many-metaverses-are-there\/."},{"key":"ref_45","unstructured":"(2024, April 04). Vogelstaller, Fabian; Buterin, Vitalik (2015): ERC-20: Token Standard (Ethereum Improvement Proposals, 20). Available online: https:\/\/eips.ethereum.org\/EIPS\/eip-20."},{"key":"ref_46","unstructured":"Ethereum (2024, January 30). ERC-20 Token Standard. Available online: https:\/\/ethereum.org\/en\/developers\/docs\/standards\/tokens\/erc-20."},{"key":"ref_47","unstructured":"Huang, Y. (2020, January 20\u201324). Traveling the token world: A graph analysis of Ethereum ERC20 token ecosystem. Proceedings of the Web Conference 2020. WWW \u201820: The Web Conference 2020, Taipei, Taiwan."}],"container-title":["Virtual Worlds"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2813-2084\/3\/2\/8\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T14:24:48Z","timestamp":1760106288000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2813-2084\/3\/2\/8"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,4,8]]},"references-count":47,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2024,6]]}},"alternative-id":["virtualworlds3020008"],"URL":"https:\/\/doi.org\/10.3390\/virtualworlds3020008","relation":{},"ISSN":["2813-2084"],"issn-type":[{"value":"2813-2084","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,4,8]]}}}