Insights on Crypto Payments, Infrastructure, and Operations

Pull-Based Oracle

Blockchain Networks & Protocols

Pronunciation: POOL bayst OR-uh-kul

Definition

A pull-based oracle lets a user or application submit a recent authenticated data report on-chain when a transaction needs it.

Overview

Contents Hide
  1. How it works and why it matters
  2. Technical context
  3. Practical checks
  4. Related concepts
  5. Further reading

How it works and why it matters

A pull-based oracle publishes authenticated observations off-chain and lets an application bring the needed update on-chain as part of an action. This can reduce repeated publication costs for feeds that are seldom consumed. The caller typically retrieves a signed report, includes it with a transaction, and an on-chain verifier checks origin, sequence, feed identifier, and age. The application must reject reports that are authentic but too old or from the wrong market; a caller should not be able to cherry-pick an outdated rate that favors them.

Technical context

In a pull-based oracle model, publishers create signed updates off-chain and make them available for consumers to retrieve.

Pull delivery can avoid continuous on-chain updates for every feed and lets applications request data close to execution.

Practical checks

Test three adversarial payloads: a properly signed but old report, a valid report for a different token pair, and a duplicate sequence submitted after a newer one. The verifier must not allow the caller to select whichever observation makes a payment cheapest or an on-chain liquidation most profitable.

Oracle; Oracle Contract; Blockchain Oracle

Further reading

Example

A customer requests a crypto checkout price. The app obtains a recently signed price update and submits it alongside the payment contract call. A stale update from yesterday may still have a valid signature, so the contract refuses it when its timestamp exceeds the allowed age.

Comparison

Pull means the consuming transaction carries the update, not that users can invent the price. A push oracle stores refreshed values independently; neither architecture proves that the original market observation is economically accurate.

Key Takeaway

Verify the feed, signature and observation time together, not just cryptographic authenticity.

Sources

  1. Base Documentation — Base (2026-07-30)
  2. Ethereum Documentation: Transactions — Ethereum Foundation (2026-07-30)