Quiz Entry - updated: 2026.07.30
Oracles can also be grouped by how they get their data. What are software, hardware, human, and computation oracles?
Software oracles read online sources (APIs, web pages); hardware oracles read the physical world through sensors; human oracles rely on people; computation oracles perform off-chain calculation.
| Type | Data source |
|---|---|
| Software | Online services — web APIs, exchange feeds, websites |
| Hardware | Physical sensors, RFID/QR scanners, IoT devices measuring the real world |
| Human | Individual people asserting or verifying facts |
| Computation | Off-chain computation whose result is too expensive or too large to run on-chain |
These describe the nature of the source, and are independent of the direction/initiator dimensions — a hardware oracle scanning a package could still be, say, a push-based inbound oracle. Hardware oracles are where the physical-to-digital trust gap bites hardest: the chain can't tell whether the sensor was honest.
Go deeper:
Blockchain oracle (Wikipedia) — lays out the software / hardware / human / computation classification of oracle types.