Historical Prices API

I. Introduction

This API endpoint allows you to fetch historical prices from Chainlink price feeds for a specified period. The API endpoint returns the price data in JSON format. You can use this API endpoint to fetch historical prices for a single round or multiple rounds. It is possible to implement this API endpoint in your smart contract using Chainlink Functions.

II. Prerequisites

• Node.js >= 14.x.x
• Yarn >= 1.22.x

III. Installation

1. Clone the repository:

git clone https://github.com/linkpoolio/historical-prices-api.git

2. Install the dependencies:

yarn install

3. Build the project:

yarn build

4. Start the server:

yarn start

5. Access UI App:

You can now access the UI app at http://localhost:3000.

6. Access the API Endpoint:

You can now access the API at http://localhost:3000/api/price.

Replace 3000 with the port number if you have a different one in your setup.

IV. API Endpoint

Endpoint

GET /api/price

Query Parameters

Required	Parameter	Description	Type	Options
✅	contractAddress	The address of the Chainlink price feed contract.	string	Price Feeds
✅	startTimestamp	The start timestamp of the period for fetching prices.	number	Unix timestamp in seconds. Example: 1681187628
✅	endTimestamp	The end timestamp of the period for fetching prices.	number	Unix timestamp in seconds. Example: 1681187628
✅	chain	The blockchain network where the contract is deployed.	string	mainnet, goerli, arbitrum, bsc, polygon , avalanche, fantom, moonbeam, moonriver, harmonyOne, optimism, metis, baseGoerli,gnosis
	rpcUrl	The RPC URL for the blockchain network.	string	RPC URLs

Response

The response is a JSON object with the following properties:

• description: The price pair name.
• decimals: The number of decimals for the answer.
• rounds: An array of round data objects. Each round data object has the following properties:
  • phaseId: The phase ID of the round.
  • roundId: The round ID.
  • answer: The price at the round.
  • timestamp: The timestamp of the round in UTC.

Errors

The API endpoint may return one of the following errors:

• Input validation error: This error is returned when the input parameters are not valid.
• Failed to get client for chain: This error is returned when the API fails to get a client for the specified blockchain network.
• Failed to get phase data from contract: This error is returned when the API fails to get phase data from the contract.

Example

Single Round Request

In order to fetch the price for a single round, you need to specify the same start and end timestamps. Make sure that the time frame exists. The API endpoint will return the price for the round that is within the specified time frame.

Request:

GET /api/price?contractAddress=0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419&startTimestamp=1614556800&endTimestamp=1614556800&chain=mainnet&rpcUrl=https://eth-mainnet.alchemyapi.io/v2/your-api-key

Response:

{
  "description": "ETH/USD",
  "decimals": 8,
  "rounds": [
    {
      "phaseId": "1",
      "roundId": "1",
      "answer": "2000",
      "timestamp": "2021-03-01T00:00:00Z"
    },
    {
      "phaseId": "1",
      "roundId": "2",
      "answer": "2100",
      "timestamp": "2021-03-01T01:00:00Z"
    }
  ]
}

Multiple Rounds Request

In order to fetch the prices for multiple rounds, you need to specify different start and end timestamps. Make sure that the start timestamp is less than the end timestamp and that the time frames exist. The API endpoint will return the prices for the rounds that are within the specified time frame.

Request:

GET /api/price?contractAddress=0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419&startTimestamp=1614556800&endTimestamp=1614643200&chain=mainnet&rpcUrl=https://eth-mainnet.alchemyapi.io/v2/your-api-key

Response:

{
  "description": "ETH/USD",
  "decimals": 8,
  "rounds": [
    {
      "phaseId": "1",
      "roundId": "1",
      "answer": "2000",
      "timestamp": "2021-03-01T00:00:00Z"
    },
    {
      "phaseId": "1",
      "roundId": "2",
      "answer": "2100",
      "timestamp": "2021-03-01T01:00:00Z"
    },
    {
      "phaseId": "1",
      "roundId": "3",
      "answer": "2200",
      "timestamp": "2021-03-01T02:00:00Z"
    },
    {
      "phaseId": "1",
      "roundId": "4",
      "answer": "2300",
      "timestamp": "2021-03-01T03:00:00Z"
    },
    {
      "phaseId": "1",
      "roundId": "5",
      "answer": "2400",
      "timestamp": "2021-03-01T04:00:00Z"
    },
    {
      "phaseId": "1",
      "roundId": "6",
      "answer": "2500",
      "timestamp": "2021-03-01T05:00:00Z"
    },
    {
      "phaseId": "1",
      "roundId": "7",
      "answer": "2600",
      "timestamp": "2021-03-01T06:00:00Z"
    },
    {
      "phaseId": "1",
      "roundId": "8",
      "answer": "2700",
      "timestamp": "2021-03-01T07:00:00Z"
    },
    {
      "phaseId": "1",
      "roundId": "9",
      "answer": "2800",
      "timestamp": "2021-03-01T08:00:00Z"
    },
    {
      "phaseId": "1",
      "roundId": "10",
      "answer": "2900",
      "timestamp": "2021-03-01T09:00:00Z"
    }
  ]
}