The Inspiration
Blockchain applications of today are severely limited by the range of use cases they can serve. Each blockchain application can only access the state via public interfaces on the same chain. Without access to the real world data, blockchains cannot be used for prediction markets, insurance, litigation, governance or any other coordination problem that is currently dependent on social institutions and corporations.
This is also known as an oracle problem. While many attempts at solving it have been made, the current solutions are too expensive and brittle to be useful at scale.
Paralink Network is building a scalable solution to the oracle problem on Polkadot. We believe that Polkadot is the optimal platform for our protocol due to its fundamental design principles: cross chain interoperability and scalability are the two key components for making Paralink secure, scalable and economically viable.

The Paralink Node
The Paralink Node is an open-source piece of software responsible for accessing real world data, and relaying it back to smart contracts via callbacks.
The Paralink Node can be run as a self-hosted solution, which offers cheap but centralized data ingress. Ideally it is run by self-organizing quorums providing a robust ingress service. Paralink Node can fetch real world data from RESTful HTTP APIs and comes with a variety of parsers (JSON, HTML, XML). Support for SQL databases and other protocols such as gRPC is planned. Furthermore, it should be possible to query confirmed state on public blockchains.
To satisfy all kinds of applications and offer the utmost flexibility, Paralink offers 3 security models with different cost, convenience and security characteristics.
Paralink’s Three Security Models
Simple Ingress
Paralink Nodes can be used as a multi-chain ingress from any 3rd party data source by any developer. Pros include being easy to implement via PQL definition, cheap and fast and having the ability to source and validate multiple information sources. This model also provides callback support for all blockchains, without need for bridges. The cons of this model are that it requires trust in node operators and is only suitable for applications that don’t have financial impact.
Trusted Ingress
Paralink’s Simple Ingress can be upgraded by the virtue of cryptographically signed PQL results with ECDSA private keys from reputable data providers. This model is suitable for Prediction Markets, Insurance, Governance and Gambling applications and easy to implement (PQL + Signing Proxy Contract). The model is cheap and fast and allows the ability for established data vendors to sell their services on Paralink Network. The model also provides Callback support for all blockchains, without need for bridges. The main con of this model is that it creates a single point of failure.
On-Chain Security
Lastly, Paralink offers an on-chain security model for applications that require the highest level of security, without having to rely on a single source of truth. This is suitable for Money Markets, Derivatives and other high-stakes financial applications and relatively easy to implement via PQL + Relayer Quorum + Bridge/XCMP. This model provides on chain aggregation and validation guarantees and the highest robustness and data quality. The cons of this model are that it requires the use of bridges, ie. Polkadot <> Ethereum, so not all chains are supported (yet) and is more expensive due to the costs of on-chain coordination.
Summary
Paralink seeks to bring the utilization of real world data in crypto applications to the mainstream through its easy-to-use PQL language, its flexibility and its lower cost compared to competitors. Paralink is now embarking on its next stage of growth by growing awareness in the community around the ability to use PQL to access real world data and create a myriad of crypto applications. In order to join in on our conversation, please join our Telegram group here: https://t.me/paralink_network.