How To Use Witnet Price Feeds
Last updated
Last updated
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.
Check this out for different examples on how to read prices from the Price Feeds Router and the Price Feeds contracts:
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:
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.
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
0x356ba62f
0x356ba62f72df54463d38fa6850079d4ca77a035bd8f193f17b10e40d67638d57
0xf723bde1
0xf723bde14abbffbe1f7e4cc11b10fcffdeb0873cadb864d13ca5fe5fa83255af
0x3a9faa5a
0x3a9faa5a41fb4ac71aee7850eda9baeae8e35cd64977afa3eaad8bcca04658d6
0x88e301ae
0x88e301ae8c594cdfbc44c57db44b36f3137f9e3ab22a718a78fb2d25c2a2a7ad
0x24beead4
0x24beead43216e490aa240ef0d32e18c57beea168f06eabb94f5193868d500946
0x21a79821
0x21a798210f2f9a59348801ac3dd2d6ba14edec757bd7bc1894181af90a7fd3a2
0x9ed884be
0x9ed884be27401b98a6c3e9d830d4288c949712e57a58235927b1a00dcd487073
0x65784185
0x65784185a07d3add5e7a99a6ddd4477e3c8caad717bac3ba3c3361d99a978c29
0x6b8258ca
0x6b8258ca2eb12b227a7f6a0962ad90723fb176285659b4dd6f755c1fc728a2ff
0x9899e356
0x9899e35601719f1348e09967349f72c7d04800f17c14992d6dcf2f17fac713ea
0x3d15f701
0x3d15f7018db5cc80838b684361aaa100bfadf8a11e02d5c1c92e9c6af47626c8
0x1a3ea43e
0x1a3ea43ec9fce5649302474844b0d2c0734ad605b3adfaf3baaab3b7ad43b1a4
0x5a352c58
0x5a352c582f56d09a9d4372befee579d09061510e65d795c20901d53fa95fb9f3
0x5825c341
0x5825c341b55f4565086205df4508d5c676990e84c479a70694d63fc781870ea0
0x38b57cfe
0x38b57cfe2aab9a063c4eaf8e57ad9f8319d106ef354cde5cf1c7575ba1c9757c
0x6d85fc1a
0x6d85fc1ab4e41a1fc4b751a289ad9e33e38534e48e98d1b2e11693cc03ede0fb
0xbd1318d3
0xbd1318d300971b390ddfb28da684ad5f54c9ca1e30c4f71cdde3f2dcce9c6b83
0xe4cc70ab
0xe4cc70abfc7ab1836bb8f6dd4888b8c4aa6f3ad1d445d2c9886e5ae2750e7e14
0x1aa645a8
0x1aa645a8e8124b720e3f7dc5162efd386f327ea59f855b1afeb8ae4c54f6f8ab
0x31debffc
0x31debffc453c5d04a78431e7bc28098c606d2bbeea22f10a35809924a201a977
0x547d1731
0x547d1731254f0589416eee8ea5d0d69147c26de8859ea5de0a9d49d2ef75bf23
0x4ba45817
0x4ba4581716a4352feaf028c4efebf2f9a3c6a03dc1030c92b74ea9c319606d7e
0x2dcfd554
0x2dcfd5546926b857978957b40dcd5164cc788079b46ce9c1abbaedac07f96837
0x92b17f49
0x92b17f49728c2c6aa29264310b084129ff8d9930618302509d63bd57e127374b
0xf75039c1
0xf75039c1cc3d4c1cec5cb42ecf19a812a123ba893e673ac920f0f8d3fcebbe34
0xf75039c1
0xf75039c1cc3d4c1cec5cb42ecf19a812a123ba893e673ac920f0f8d3fcebbe34
0xc4ec7fbc
0xc4ec7fbc6384f83dad668488519c7195acafd67645ebcc7f76a84d77feaca2fb
0xe2960cc0
0xe2960cc030131ae6ce0d14aea9ecfa937461aa22d2d55a36b44b27737a11bd75
0xfb2c7795
0xfb2c779532e89f660244ccdd71749e8d75b3e53a8fc0d5531ef814f8b8300eef
0x465eb519
0x465eb5194898a1ee043df9dd69d130c648847c0bed777fe413d065b62d2891c5
0x6278c724
0x6278c7245d4d468f46c10f2963d2f9eb36f4bfb5c19dda54f0bfd5d0db83e9b6
0x84aea78e
0x84aea78ea133106231c0aa5aa36d49dcf6480c55e12b140de2f713ebe4f6fb0c
0x4c80cf2e
0x4c80cf2e5b3d17b98f6f24fc78f661982b8ef656c3b75a038f7bfc6f93c1b20e
0x538f5a25
0x538f5a25b39995a23c24037d2d38f979c8fa7b00d001e897212d936e6f6556ef
0x98d36ccb
0x98d36ccbb4bde86f4533dbd6577ccfd8be1ec4175d9fe3aae52079d0950ba36d
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.
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.
