📂 Reference

Terminology

Table of Contents

• Airnode
• API Card
• Base URL
• Blockchain Providers
• Cloud Provider
• Deployment
• Endpoint
• Heartbeat
• HTTP
• Integration
• Mainnet
• Mnemonic
• Parameters
• Path
• Reserved Parameters
• Security Schemes
• Versioning

The general terms used by ChainAPI follow standard blockchain and REST API definitions. Other related Airnode Concepts and Definitions may be useful to better understand how Airnode works.

Airnode

Airnode is a serverless oracle node implemented with a "set and forget" philosophy. Airnode is composed of two parts: the off-chain Airnode (a.k.a. "the node") deployed as self-hosted or cloud provider functions (e.g., AWS or GCP) and the on-chain protocol contract AirnodeRrpV0.sol.

API Card

A UI component of the ChainAPI app that contains information about a data provider’s connected API or integration. A data service provider can have multiple API integrations for a single account.

Base URL

REST APIs have a base URL to which the endpoint paths are appended. A base URL is defined by a scheme, host, and basePath on the root level of the API specification. (i.e. https://www.domain.com/basepath/)

basePath is the URL prefix for all API paths, relative to the host root. It must start with a leading slash /. If basePath is not specified, it defaults to /, that is, all paths start at the host root.

Also see Path below on this page.

Blockchain Providers

Blockchain node providers offer blockchain nodes and blockchain node hosting as a service. Blockchain nodes are essential for a functioning blockchain because the nodes store a full copy of the distributed ledger, and are necessary for blockchain developers to build decentralized applications. For Airnode they provide RPC access to a desired blockchain. Also see Chain Providers in the Airnode documentation set.

Cloud Provider

Cloud providers host remote services such as serverless. Airnode can be deployed to either AWS or GCP. Using a serverless service minimizes the infrastructure an API provider must maintain. Airnode (implemented using nodejs (opens new window)) runs effortlessly in a serverless environment.

Deployment

The process of pushing code to operate as an executable service on a server. ChainAPI builds the required integration file needed to deploy an Airnode to either AWS or GCP. As a result, the Airnode will be able to communicate directly with an API provider's API endpoints and provide data to a desired blockchain either directly using RRP or through dAPIs.

Endpoint

An endpoint is a resource of an API. It is the path in an API URL that points to a specific subset of information from the data set of an API. A ChainAPI integration defines endpoints that target specific API resources accessed by an Airnode.

Heartbeat

A response from an API that indicates the API is active and working. Airnode can provide a webhook style heartbeat as an indicator that is is up and running. Setup of the heartbeat is an advanced configuration.

HTTP

An application-layer protocol (scheme) for transmitting hypermedia documents, such as HTML. An HTTP request is made by a client, to a named host, which is located on a server. The aim of the request is to access a resource on the server. There is a more secure version called HTTPS. HTTPS is commonly used to access REST API resources using endpoint declarations in a URL.

Integration

A connection between two services. Use ChainAPI integrations to create a definition file that defines the connection between an Airnode and an API provider's API data resources.

Mainnet

Every blockchain project has a mainnet. Mainnets are considered production environments. A mainnet is a blockchain that actually carries out the execution and functionality of on-chain real-world transactions. This is different from a testnet, which acts as a test of such transaction execution and functionality.

Mnemonic

Sometimes refereed to a seed phrase or secret recovery phrase. A mnemonic is used to create a digital wallet. ChainAPI currently supports MetaMask digital wallets. Hardware wallets connected to MetaMask are also supported.

Parameters

Parameters are passed to an API endpoint allowing it to filter an API's data resources. The API endpoint uses the parameters to source a response. Endpoints and their parameters are a fundamental requirement to complete a ChainAPI integration which integrates an Airnode to a set of API endpoints.

Path

Path is the part of a URL that comes after the base URL.

https://www.mydomin.com/v1/user/15
/*
scheme   → https://
host     → www.domain.com
basePath → /v1
path     → /user/15
*/
https://www.mydomin.com/user/15 // no basePath
/*
scheme   → https://
host     → www.domain.com
basePath → implied as /
path     → /user/15
*/

Reserved Parameters

Reserved parameters are used internally by Airnode. They do not map to normal API endpoint parameters. They are used by Airnode for special purposes.

• Endpoint parameters - Airnode endpoint parameters are mapped to API operation parameters.
• Reserved parameters - Reserved parameters perform a specific operation on the response before fulfilling the request. Reserved parameter names start with _.

See Reserved Parameters in the OIS documentation set.

Security Schemes

A security scheme specifies the security settings for a particular API; for example, an API key. An Airnode can use the following security scheme types to authenticate itself to API endpoints.

• apiKey
• http
  • basic
  • bearer

See API Security in hte Airnode documentation set.

Versioning

Versioning is the creation and management of multiple product releases, all of which have the same general function, but are improved, upgraded or customized. ChainAPI creates a new version of an integration each time it is updated.