How To Use Witnet Price Feeds

The preferred way to consume the Witnet-powered price feeds is through the Price Feeds Router.

This smart contract is deployed in all the supported chains and allows your own smart contracts and Web3 applications to get the latest price of any of the supported currency pairs by providing the identifier of the pair to a single Solidity method. This removes the need to know the actual contract addresses handling the price updates from the Witnet oracle.

Alternatively, the Price Feeds Router also lets you find out the actual address of the Price Feed contract that is currently serving a specific currency pair (if that pair is supported in your chain).

While all the supported currency pairs are automatically updated in a timely manner according to their different update conditions, you can always use the Price Feed contracts to trigger a new price update at any time, if willing to pay the required gas for that.

Code examples

Check this out for different examples on how to read prices from the Price Feeds Router and the Price Feeds contracts:

using-witnet-data-feeds.md

Update conditions

Different price feeds are updated with different periods or every time that certain conditions are met. You can find all the conditions for updating here:

triggering-conditions.md

Currency pairs

Currency pairs are identified by a bytes32 value, calculated as the keccak256 hash of the currency pair caption. The caption is composed as the string concatenation of: Price-, first asset denomination (e.g. BTC), /, second asset denomination (e.g. USD), -, and the number of decimals.

TIP

For the sake of simplicity, currency pairs served by the Witnet's Price Router can also be identified by just using the first 4 bytes (see ID4 below) of the full bytes32 identifier (ID32).

This table contains all the currency pairs that are currently being updated on a regular basis:

Caption	ID4	ID32
Price-AVAX/USD-6	0x356ba62f	0x356ba62f72df54463d38fa6850079d4ca77a035bd8f193f17b10e40d67638d57
Price-BOBA/USDT-6	0xf723bde1	0xf723bde14abbffbe1f7e4cc11b10fcffdeb0873cadb864d13ca5fe5fa83255af
Price-BORING/USDT-6	0x3a9faa5a	0x3a9faa5a41fb4ac71aee7850eda9baeae8e35cd64977afa3eaad8bcca04658d6
Price-BCH/USD-6	0x88e301ae	0x88e301ae8c594cdfbc44c57db44b36f3137f9e3ab22a718a78fb2d25c2a2a7ad
Price-BTC/USD-6	0x24beead4	0x24beead43216e490aa240ef0d32e18c57beea168f06eabb94f5193868d500946
Price-CELO/EUR-6	0x21a79821	0x21a798210f2f9a59348801ac3dd2d6ba14edec757bd7bc1894181af90a7fd3a2
Price-CELO/USD-6	0x9ed884be	0x9ed884be27401b98a6c3e9d830d4288c949712e57a58235927b1a00dcd487073
Price-CFX/USDT-6	0x65784185	0x65784185a07d3add5e7a99a6ddd4477e3c8caad717bac3ba3c3361d99a978c29
Price-CRO/USDT-6	0x6b8258ca	0x6b8258ca2eb12b227a7f6a0962ad90723fb176285659b4dd6f755c1fc728a2ff
Price-DAI/USD-6	0x9899e356	0x9899e35601719f1348e09967349f72c7d04800f17c14992d6dcf2f17fac713ea
Price-ETH/USD-6	0x3d15f701	0x3d15f7018db5cc80838b684361aaa100bfadf8a11e02d5c1c92e9c6af47626c8
Price-FRAX/USDT-6	0x1a3ea43e	0x1a3ea43ec9fce5649302474844b0d2c0734ad605b3adfaf3baaab3b7ad43b1a4
Price-FXS/USDT-6	0x5a352c58	0x5a352c582f56d09a9d4372befee579d09061510e65d795c20901d53fa95fb9f3
Price-GLINT/USD-6	0x5825c341	0x5825c341b55f4565086205df4508d5c676990e84c479a70694d63fc781870ea0
Price-GLINT/USDC-6	0x38b57cfe	0x38b57cfe2aab9a063c4eaf8e57ad9f8319d106ef354cde5cf1c7575ba1c9757c
Price-GLINT/USDT-6	0x6d85fc1a	0x6d85fc1ab4e41a1fc4b751a289ad9e33e38534e48e98d1b2e11693cc03ede0fb
Price-GLMR/USD-6	0xbd1318d3	0xbd1318d300971b390ddfb28da684ad5f54c9ca1e30c4f71cdde3f2dcce9c6b83
Price-GLMR/USDT-6	0xe4cc70ab	0xe4cc70abfc7ab1836bb8f6dd4888b8c4aa6f3ad1d445d2c9886e5ae2750e7e14
Price-IMMO/MCUSD-6	0x1aa645a8	0x1aa645a8e8124b720e3f7dc5162efd386f327ea59f855b1afeb8ae4c54f6f8ab
Price-KCS/USDT-6	0x31debffc	0x31debffc453c5d04a78431e7bc28098c606d2bbeea22f10a35809924a201a977
Price-KSW/USD-6	0x547d1731	0x547d1731254f0589416eee8ea5d0d69147c26de8859ea5de0a9d49d2ef75bf23
Price-METIS/USDT-6	0x4ba45817	0x4ba4581716a4352feaf028c4efebf2f9a3c6a03dc1030c92b74ea9c319606d7e
Price-MJT/KCS-9	0x2dcfd554	0x2dcfd5546926b857978957b40dcd5164cc788079b46ce9c1abbaedac07f96837
Price-MOVR/USDT-6	0x92b17f49	0x92b17f49728c2c6aa29264310b084129ff8d9930618302509d63bd57e127374b
Price-OKT/USDT-6	0xf75039c1	0xf75039c1cc3d4c1cec5cb42ecf19a812a123ba893e673ac920f0f8d3fcebbe34
Price-OLO/USDC-6	0xf75039c1	0xf75039c1cc3d4c1cec5cb42ecf19a812a123ba893e673ac920f0f8d3fcebbe34
Price-OMG/BTC-9	0xc4ec7fbc	0xc4ec7fbc6384f83dad668488519c7195acafd67645ebcc7f76a84d77feaca2fb
Price-OMG/ETH-9	0xe2960cc0	0xe2960cc030131ae6ce0d14aea9ecfa937461aa22d2d55a36b44b27737a11bd75
Price-OMG/USDT-6	0xfb2c7795	0xfb2c779532e89f660244ccdd71749e8d75b3e53a8fc0d5531ef814f8b8300eef
Price-SAX/USDT-6	0x465eb519	0x465eb5194898a1ee043df9dd69d130c648847c0bed777fe413d065b62d2891c5
Price-STELLA/USD-6	0x6278c724	0x6278c7245d4d468f46c10f2963d2f9eb36f4bfb5c19dda54f0bfd5d0db83e9b6
Price-STELLA/USDT-6	0x84aea78e	0x84aea78ea133106231c0aa5aa36d49dcf6480c55e12b140de2f713ebe4f6fb0c
Price-USDC/USD-6	0x4c80cf2e	0x4c80cf2e5b3d17b98f6f24fc78f661982b8ef656c3b75a038f7bfc6f93c1b20e
Price-USDT/USD-6	0x538f5a25	0x538f5a25b39995a23c24037d2d38f979c8fa7b00d001e897212d936e6f6556ef
Price-VSQ/DAI-6	0x98d36ccb	0x98d36ccbb4bde86f4533dbd6577ccfd8be1ec4175d9fe3aae52079d0950ba36d

TIP

Clicking on any of the captions above will take you to the Javascript equivalent of the RADON script that is processed by the Witnet oracle on every single price update of the corresponding currency pair.

INFO

As introduced by the 2017 Witnet whitepaper, RADON is "a flow-based, tacit, point-free scripting language [...] implemented as a domain specific language (DSL), [... that] includes normalization and aggregation methods in a MapReduce style".

Basically, it specifies the math, filters, reducers and tally operator to apply to the values fetched from a set of given sources, as well as the witnessing thresholds and quality levels to be met by the Witnet oracle when solving the price update.