Blocksize is a Data Provider on the API3 Network

API3 is a first-party oracle network. Instead of relying on third-party node operators to fetch and relay data, API3 has the data providers themselves deliver their data on-chain directly. This removes the middleman layer between the source and the blockchain, so applications get data straight from the firms that actually produce it — across 100+ data feeds on every major chain.

Every layer between the source and the chain is a place where data can break, lag, or be tampered with. API3's first-party model removes that layer: the provider runs the connection itself, so the data on-chain comes directly and accountably from its origin. The trade-off is that the network is only as good as the providers behind it — which is exactly why the quality of each source matters.

Blocksize is a data provider on the API3 Network. We deliver our own aggregated, real-time crypto market data directly into API3 — the same feed we provide to our customers off-chain. As a first-party source, our data reaches the chain straight from us, with no intermediary that could distort it on the way.

If any part of your portfolio touches DeFi — on-chain derivatives, lending protocols, structured products with crypto underlyings — the prices that govern those positions are set by oracle consensus, not by any single exchange. A trader might see one price on Binance, but liquidations, settlements, and margin calls on-chain are triggered by the oracle price. Blocksize delivers those exact oracle-grade prices off-chain into your systems, so your risk models reflect the same reality that smart contracts act on.
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We are the only data provider whose feeds are simultaneously battle-tested on-chain — securing $38.85B across 7 leading oracle networks — and delivered off-chain to institutional systems. This means your compliance, risk, and trading teams receive the exact same oracle-grade prices that govern DeFi smart contracts, validated by decentralized consensus.

A single exchange only shows its own order book, which can drift from the real market — on even the most liquid pair, only about 20–25% of a top exchange's quotes sit within the true multi-venue fair value, and during stress a venue can diverge by 10 basis points or more. Listing sites like CoinGecko show a reference average, not a real-time, validated feed you can build on. We aggregate across 70+ venues in real time, filter outliers, and down-weight drifting sources — so you get the consensus price the whole market agrees on, not one venue's version of it.

As a tier-one oracle data publisher, every price update we produce is independently verified by multiple node operators across decentralized oracle networks like Chainlink, Pyth, and Redstone. Submissions that deviate from consensus are rejected, and operators providing inaccurate data face financial penalties. This creates continuous, real-time quality enforcement — not quarterly audits, but every single block.

Blocksize operates under German jurisdiction with full transparency and a strong focus on institutional-grade compliance.
We follow regulatory best practices to meet the expectations of banks, asset managers, and professional investors — delivering secure, non-custodial services with clear legal alignment.