> For the complete documentation index, see [llms.txt](https://docs.publicindex.network/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.publicindex.network/open-index-protocol/what-is-oip.md).
# What is OIP?
[**Open Index Protocol**](https://www.openindexprotocol.com/) (OIP) is an open source specification for a persistent worldwide index and file library useful for data publishing, file distribution and facilitating direct payments.
OIP uses PIN to operate with no central authority: record indexing, file storage/distribution and transaction management are carried out collectively by the decentralized network. OIP is the first **permissionless system** with a decentralized and transparent index for digital content and protected file persistence.
The system uses a **Salutary Protocol model**, which funnel financial incentive to both application and protocol layers, ensuring sustainability and antifragility of the system through open market incentive alignment of all participants.
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**Learn more about OIP here:**
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