What an oracle is in the context of decentralised systems, why oracles are needed, and how they deliver trustworthy outside information.
A self-contained decentralised program can only reason about information that already exists inside its own environment. On its own, it cannot simply “look up” something happening in the outside world. This limitation is why oracles exist.
An oracle is a bridge that carries outside information into that self-contained environment in a way the program can rely on.
The hard part is not moving information — it is trusting it. If a program relied on a single source for its outside information, that source could be wrong, offline, or deliberately misleading, and the program would have no way to tell.
The Flare networks address this by gathering the same information from many independent participants and combining their inputs, so that no single source has to be trusted on its own. This is the guiding idea behind the built-in FTSO.
Reliable outside information unlocks a much wider range of useful applications. For that reason, the Flare networks treat trustworthy, decentralised data delivery as a first-class capability rather than an afterthought. Learners will find the oracle concept comes up again and again.
This article is part of the Flare Portal wiki — a free, independent educational reference. It is a conceptual overview and not a substitute for primary technical documentation.