dYdX vs MercadoBitcoin

dYdX is a decentralized perpetuals exchange that migrated from its StarkEx-based v3 to a Cosmos-chain v4 architecture, replacing the old exchange API with an open-source Indexer exposing markets, orderbooks, trades, and candles over REST and WebSocket. Anyone can run their own Indexer instance, but the public one at indexer.dydx.trade needs no signup for market-data reads — it's rate-limited rather than API-key gated.

Mercado Bitcoin is Brazil's oldest and largest cryptocurrency exchange, operating since 2013 with spot trading across dozens of BRL pairs. Its v4 REST API and companion WebSocket service expose public market data — candles, order books, tickers — without authentication, while trading and account endpoints require an API key created from account settings. The API is free to use for individual developers.