LEARN / DATA EXPLAINER
Where a price chart comes from
Every chart is a chain of observations and choices. Trace it back before treating it as a price you could trade, or a chart you could republish.
Three routes from activity to a chart
Centralized exchange: records from a venue
On a centralized venue, orders meet in its matching system. The latest matched trade is one possible “last price.” A candle groups trade information into a time window, commonly showing open, high, low and close. Coinbase's official trades API identifies trade time, price and size, and the resting order on the book. The venue supplies the data through its services; access does not by itself grant republication rights. Coinbase docs ↗
On-chain pool: a public transaction trail
In an automated liquidity pool, a swap changes pool balances and price according to the pool's rules. Uniswap v2 documents a constant-product design. Swaps recorded on a public chain can be read and used to reconstruct a venue-specific price series. Different pools or indexers may still disagree because of selection, timing, fees and reconstruction choices. The public transaction trail does not remove every provider's terms for an enriched feed. Uniswap ↗
Oracle: a reference value, not a fill
An oracle can combine prices from data publishers and make a reference value available to smart contracts. Pyth and Chainlink describe different aggregation paths. The result is useful for a contract but is not an order-book quote or proof that an order of your size could fill there. Pyth ↗ Chainlink ↗
For CouchChange, source provenance and publication permission are separate checks. We can explain how a study works while keeping recorded Kraken-derived prices, fills and account values private until rights are resolved.
Sources
Examples marked made-up numbers are invented. Nothing in this lesson is a recorded CouchChange result or a recommendation.
Try it
An oracle says $100 and a DEX pool quotes $99. Which number is the guaranteed sale price for ten tokens?
Think it through, then open an answer
Neither. The oracle is a reference. The pool price depends on size and current state, plus fees; a real trade may differ.