Reference → dAPIs → Understanding dAPIsdAPIs
dAPIs are on-chain data feeds sourced from off-chain first-party oracles owned and operated by API providers themselves and are continuously updated using signed data. dApp owners can read the on-chain value of any dAPI in realtime.
dAPIs can serve a variety of continuously updated streams of off-chain data, such as the latest cryptocurrency, stock, and commodity prices. They can power various decentralized applications such as DeFi lending, synthetic assets, stable coins, derivatives, NFTs, and more.
Values stored on-chain
Datafeed values are stored on-chain within the Api3ServerV1.sol contract and are updated on the basis of beaconIds. To provide aggregated data, collection of multiple beaconIds are aggregated using a median function on-chain and used to update the beaconSetId which is a keccak256() hash representation of all the underlying beaconIds. Beacon sets get updated by updating each underlying beacon using updateBeaconWithSignedData and then calling the function updateBeaconSetWithBeacons to update the beacon set.
dAPIs are human-readable mappings that maps to a beaconId or beaconSetId. The beaconId for each dAPI gets updated when the price hits the set deviation threshold/heartbeat using Signed-APIs. Airseeker and other entities who have access to signed data are responsible for updating each individual beaconId for each dAPI.
A beaconId for each dAPI is derived from the hash of the provider's Airnode's address and its Template ID(a hash of one of the Airnode's endpointId and encoded parameters).
API3 is running Airseekers which are primarily responsible for updating the beaconId based on the specification of the dAPI. Data Providers also update the beaconId at a higher deviation threshold/heartbeat as a fallback. There are also other entities that serve as additional fallback which operate at an even higher deviation threshold/heartbeat.
Apart from relying on just the Airseeker to look for price deviations, searchers can bid for price updates through the OEV Network to update the data feeds.
Airseeker
Airseeker is a serverless lambda function that is responsible for updating the values of each beaconId for each dAPI. It is used to update the beacons with signed responses from Signed-API. Signed-API receives signed data from the data providers via Airnode-Feed.
Similar to Airnode's OIS, Airseeker also requires a configuration file that is used to configure the Airseeker. Click here to see an example of an Airseeker configuration file. The configuration file is used to configure the deviation thresholds and heartbeat for each beaconId or beaconSetId.
Providers for dAPIs
Providers for blockchain data such as Liquid Staking Derivatives (LSDs) and Liquid Staking Tokens (LSTs):
- Ankr
- BlastAPI
- Blocksize
- drpc
- Nodary
Providers for cryptocurrency prices:
- Coingecko
- Coinmetrics
- Coinpaprika
- dxFeed
- Finage
- Kaiko
- NCFX
- Nodary
- Twelvedata
All the data providers listed here are selected and properly tested by the dAPI team to ensure the highest quality data availability for the listed dAPIs.
Chains
dAPIs are available on both major EVM-compatible testnets and mainnets. Head over to the API3 Market to see lists of all chains and the dAPIs on each.
Update Process
When a user places an order for a dAPI, the order will be created on-chain and the mapping for the dAPI will be updated to point to the particular beaconSetId with the requested deviation threshold and heartbeat.
Note
Purchasing a better configuration will not change the proxy contract address for the dAPI.
With dAPIs, dApps can have an option to configure the deviation threshold and heartbeat. For both mainnet and testnet feeds, dApps have the following options to choose from based on the chain and dAPI:
| Deviation | Heartbeat |
|---|---|
| 0.25% | 24 hours |
| 0.5% | 24 hours |
| 1% | 24 hours |
| 5% | 24 hours |
See the guide Subscribing to dAPIs and learn more on how to access dAPIs.
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