# Terminology
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 providerβs 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 β https://
host β www.domain.com
basePath β /v1
path β /user/15
*/
https://www.mydomin.com/user/15 // no basePath
/*
scheme β https://
host β www.domain.com
basePath β implied as /
path β /user/15
*/
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# 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.
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