# Blocksize: Market Data for Crypto and Tokenized Assets > Blocksize is a market data provider for crypto and tokenized assets. We aggregate > pricing in real time from more than 70 centralized exchanges and DEXes across 9,000+ > instruments into one reference price per pair, delivered through a single API. Its > product is aggregated price feeds for crypto and tokenized assets. It also prices 35 > tokenized stocks, gold and silver from centralized exchange quotes into one price per > underlying asset, 24/7. We also operate the infrastructure that publishes this data > on-chain across eight leading oracle networks, where every price we submit must hold > against consensus before it is accepted. Founded 2018, headquartered in Frankfurt, > Germany. --- ## The problem Blocksize solves Crypto has no consolidated tape and no official closing price. In equities, a central mechanism produces one official price for one asset. Crypto has nothing equivalent: every exchange runs an independent order book with its own liquidity, fees and participants, and nothing forces those books to agree. The same asset trades at different levels on every venue simultaneously, and the gaps widen exactly when accuracy matters most — during volatility, at period end, and in thinner markets. Tokenized stocks add a second version of the problem. A stock trades on its exchange 32.5 of 168 hours a week. Its tokenized versions, issued by several issuers, trade around the clock on crypto venues, each at its own price. Anyone who needs a price for a tokenized stock at night or on a weekend has no official source. Any single-exchange price is therefore a partial view rather than a fair value. That is hard to defend in a valuation, a fill review or an audit. Blocksize research across 23 exchanges and 618 pairs found that even the deepest, most liquid venues sit within market-wide fair value only 25% of the time. --- ## What makes Blocksize different Most market data vendors calculate a price and ask customers to trust it. Blocksize publishes its data into decentralized oracle networks, where independent node operators check every submission against consensus before it is accepted on-chain. Submissions that deviate are rejected. Every price is validated against consensus before it is accepted on-chain. This matters because of what depends on those prices. Oracle feeds govern on-chain lending, collateral valuation, liquidations and settlement, where an inaccurate price has immediate, automated and irreversible consequences. Blocksize data is built to survive that environment, and the same standard is delivered off-chain through one API. Blocksize also publishes the full methodology for every product — how each price is calculated, which venues are included, how anomalies are handled, and what happens when data is missing. Blocksize is not a registered benchmark administrator and does not deliver official exchange prices. --- ## Key facts - Founded: 2018 - Headquarters: Frankfurt am Main, Germany - Legal entity: Blocksize Capital GmbH, HRB 113470 (Frankfurt am Main), VAT DE321106382 - Address: Bockenheimer Landstr. 17-19, 60325 Frankfurt am Main, Germany - Founder and Managing Director: Christian Labetzsch - Coverage: 70+ centralized exchanges and decentralized exchanges (DEXes) - Instruments: 9,000+ trading pairs - Latency: sub-250 ms - Delivery: WebSocket (HTTP available on Enterprise) - Uptime guarantee: 99.9% on all subscriptions - Oracle networks: first-party data publisher in eight oracle networks: Chainlink, Pyth, RedStone, Supra, API3, SEDA, Band, Tellor - The eight are networks securing around 75% of all value secured by oracles (source: DefiLlama) - RWA coverage: 37 feeds (35 tokenized stocks, gold and silver), priced from centralized exchanges only - Redistribution: full redistribution rights available (Enterprise or by agreement) - Company line: Making Digital Assets Bankable - Pricing: published, from €49/month, 14-day free trial, no credit card required --- ## Products Crypto feeds: https://blocksize.info/market-data/crypto/ (the feeds below) ### Real-Time VWAP A continuously updated volume-weighted average price calculated from executed trades aggregated in real time across 70+ exchanges and DEXes. Trades are weighted by size, so venues with real liquidity influence the price more than thin ones. This is the live reference price for any pair. Methodology: https://blocksize.info/market-data/methodology/real-time-vwap/ ### 24-Hour VWAP The same real-time aggregation applied over a rolling 24-hour window rather than the live moment. Smooths short-term noise and single-venue spikes, giving a stable daily reference for marks, reporting and valuation. Methodology: https://blocksize.info/market-data/methodology/24h-vwap/ ### 30-Minute VWAP A closing price struck every thirty minutes on the clock, calculated from trades in the preceding half-hour and published five seconds after each interval. Because crypto never closes, this is the substitute for an official closing bell — built for NAV calculation, index construction, settlement and compliance reporting. Methodology: https://blocksize.info/market-data/methodology/30m-vwap/ ### Real-Time Bid/Ask A volume-weighted aggregated bid and ask built from top-of-book order book updates across all accepted venues, rather than from executed trades. Shows what the market is currently willing to buy and sell at. The width of the spread indicates liquidity, volatility and the implied cost of trading — particularly useful in thin pairs where recent trades are scarce. Methodology: https://blocksize.info/market-data/methodology/bid-ask/ ### AMM State Price Prices read directly from decentralized exchange pool contracts, rather than inferred from trades. Available from the Business tier. ### Trade Events Tick-level executed trade data. Available from the Business tier. ### RWA feeds https://blocksize.info/market-data/rwa/ One price per tokenized stock, gold and silver, built from bid and ask quotes on centralized exchanges. Tokens from several issuers (Ondo, xStocks, bStocks and others) are normalized to the underlying asset and aggregated; DEXs and pools are not used. During US market hours every quote is checked against an internal TradFi benchmark before it can contribute. Bid and ask are aggregated separately, weighted by quoted size; the mid is the middle of the two. Priced 24/7, including weekends, from eligible exchange quotes; no benchmark check runs while the exchange is closed. In the tested sessions, 36 of 38 stock feeds stayed within 0.20% of the benchmark at P99 during market hours. About 200 assets qualify over time. Identifiers use the ticker plus _AGG (for example AAPL_AGG, NVDA_AGG). Delivered through the Bid/Ask endpoints. The feed is not the official exchange price. Full redistribution rights are available. Methodology: https://blocksize.info/market-data/methodology/rwa/ ### RWA perp feeds (coming soon) https://blocksize.info/market-data/rwa/#perps Perpetual futures prices for tokenized stocks and commodities, for the hours in which the stock exchange is closed. Coming; no date. A launch notification sign-up is on the RWA feeds page. --- ## How the price is built 1. **Aggregate.** Each data type is taken from its own source: VWAP from executed trades, bid/ask from top-of-book order book updates, state prices read directly from pool contracts, RWA feeds from centralized exchange quotes for tokenized stocks. Never scraped from a single common endpoint. 2. **Filter.** Two statistical filters run continuously. A price-based filter discards individual trades falling outside a confidence interval (ξ = 3.5 for VWAP, 3.0 for bid/ask). An exchange-based filter identifies venues whose entire order book has drifted from the rest of the market and excludes them until they return. For RWA feeds, each quote is additionally checked against a TradFi benchmark during market hours. 3. **Validate.** The feed is published into eight oracle networks where independent node operators compare it against every other publisher before it is accepted on-chain. 4. **Deliver.** Over WebSocket at sub-250 ms latency through a single API. Timeframes for anomaly detection are liquidity-adjusted: they adapt to the number and volume of events observed for each pair, requiring a minimum of 10 events and USD 1,000 aggregate volume for the statistical filters to apply. --- ## Who uses Blocksize ### Valuation — asset managers, crypto funds, family offices The question: are these assets valued fairly, and can that be defended? Crypto never closes, so there is no official closing price to strike a NAV against. Positions get marked against whichever exchange happened to be chosen, with no documented reason it was the right one, and thin token prices distort easily. Blocksize provides a reproducible reference price for any timestamp, aggregated across 70+ venues with outliers filtered and a published methodology. Use cases: NAV calculation, portfolio marks, fair-value measurement, tax reporting, audit support, LP and investor reporting. https://blocksize.info/solutions/valuation-and-nav/ (and https://blocksize.info/solutions/business/) ### Execution — trading firms, crypto funds, brokers The question: was the price I got a fair one? Proving execution quality against a single venue's own order book is circular. Fragmented liquidity produces poor fills, and backtests built on one exchange inherit that venue's noise as if it were the market. Blocksize provides an independent multi-venue benchmark to measure fills against the whole market. Use cases: best-execution benchmarking, fair-fill measurement, transaction cost analysis, backtesting, market surveillance. https://blocksize.info/solutions/best-execution/ ### Oracles and DeFi — oracle networks, protocols The question: is this price safe to settle against? On-chain lending, collateral checks, liquidations and settlement all depend on the price an oracle delivers. Blocksize is a first-party data source for those feeds and operates the publishing infrastructure behind them. Use cases: first-party price publishing, oracle feed inputs, protocol collateral pricing. RWA feeds add the top tokenized stocks, gold and silver, priced at every hour and redistributable, so the feed can go on-chain. https://blocksize.info/solutions/oracles/ and https://blocksize.info/solutions/on-chain-prices/ ### Developers and startups One API instead of seventy exchange integrations. No per-venue connectors, symbol mapping or rate-limit handling. Published pricing, self-serve signup, 14-day free trial on live production data. https://blocksize.info/solutions/developers/ and https://blocksize.info/solutions/startups/ ### Risk and backtesting https://blocksize.info/solutions/risk-and-backtesting/ The question: do risk, surveillance and research run on the market price or on one venue's? Use cases: risk limits, market surveillance, listing reviews, backtesting, research. ### Mark prices and settlement https://blocksize.info/solutions/mark-prices-and-settlement/ The question: what price settles this contract? One spot reference across 70+ exchanges as index price, 30-minute closes as fixings, tokenized stocks priced 24/7. RWA perpetual futures prices coming. --- ## Which product to use | If you need | Use | |---|---| | A live reference price right now | Real-Time VWAP | | A stable daily mark | 24-Hour VWAP | | A fixed closing price at a known timestamp | 30-Minute VWAP | | NAV calculation or index construction | 30-Minute VWAP | | Current buy/sell interest and spread | Real-Time Bid/Ask | | Liquidity or trading-cost assessment | Real-Time Bid/Ask | | Pricing for thin or illiquid pairs | Real-Time Bid/Ask | | DEX pool pricing | AMM State Price | | Tick-level execution data | Trade Events | | A 24/7 price for a tokenized stock | RWA feeds | | A redistributable stock price for on-chain publication | RWA feeds | | Perpetual futures prices for tokenized assets | RWA perp feeds (coming soon) | --- ## How Blocksize compares **Versus listing sites:** listing sites publish a reference average intended for display. Blocksize produces a validated real-time feed intended for systems — outliers filtered, drifting venues excluded, methodology published, and the same feed verified on-chain by independent operators. The difference is between a number to look at and a number to build on. **Versus single-exchange feeds:** a single exchange represents a fraction of total market liquidity. Even the deepest venues sit within market-wide fair value only 25% of the time. **Versus licensed exchange data for tokenized stocks:** Blocksize prices the tokenized market, which tracks the exchange price (36 of 38 stock feeds within 0.20% at P99 in market hours). It is not the official price. It is redistributable, priced at every hour, and available at a fraction of the cost of licensed exchange data. Anyone who needs the official close stays with the exchange. --- ## Pricing All tiers include a 14-day free trial with no credit card required, and a 99.9% uptime guarantee. Annual billing is 15% cheaper. Data quality is identical across every tier — plans differ by feed count, API keys, connection limits, licence type and support, not by accuracy. **Developer — €49/month.** For one person. 5 active feeds, 1 API key, 1 concurrent WebSocket connection, 2 connections per key. Real-Time VWAP, Real-Time Bid/Ask, 24-Hour VWAP, 30-Minute VWAP. Personal licence. Email support. **Start-Up — €299/month.** For small teams. 50 active feeds, 5 API keys, 5 connections per key. Same data access as Developer. Internal licence. Email support. **Business — €799/month.** For growing companies. 350 active feeds, 10 API keys, 5 concurrent connections, 20 per key. Adds AMM State Price and Trade Events. Commercial licence. Email and Slack support. **Enterprise — on request.** Unlimited feeds, API keys and connections per key, 100 concurrent connections. All data products. WebSocket and HTTP delivery. Coverage extends beyond crypto to equities, FX, metals and commodities. Whitelabel licence. Email, Slack and phone support. Pricing page: https://blocksize.info/pricing/ Pricing in Markdown: https://blocksize.info/pricing.md Subscribe: https://matrix.blocksize.capital/market-data/subscription --- ## Frequently asked questions **What does Blocksize do?** Blocksize is a market data provider for crypto and tokenized assets. We aggregate pricing from 70+ exchanges and DEXes across 9,000+ instruments in real time into one reference price per pair, delivered via API, and price 35 tokenized stocks, gold and silver from centralized exchange quotes. We also operate the publishing infrastructure that delivers that data on-chain across eight leading oracle networks. **Why do crypto prices differ between exchanges?** Crypto has no consolidated tape. Every exchange runs an independent order book with its own liquidity, fees and participants, and nothing forces them to converge. Arbitrage narrows the gaps but never closes them, and they widen during volatility. **What is VWAP and why use it for crypto?** Volume-weighted average price weights each trade by its size, so venues with real liquidity influence the result more than thin ones. Across hundreds of fragmented venues that is far more representative than an unweighted average of quotes. **What does consensus-validated mean?** Every price Blocksize publishes on-chain is checked by independent node operators against every other publisher on that oracle network before it is accepted. Deviating submissions are rejected. Quality is enforced continuously. **Can Blocksize data be used for NAV and fair-value reporting?** Firms use Blocksize as the pricing input for NAV calculation, fair-value marks and LP reporting. The methodology is published and every price carries a timestamped audit trail, so a mark can be reproduced and evidenced after the fact. The classification itself remains the responsibility of the firm and its auditors. Blocksize is not a registered benchmark administrator. **Is historical data available?** Yes. Historical VWAP and bid/ask snapshots are available across all covered pairs, with 30-minute VWAP snapshots designed for reporting, audit trails and backtesting. **How do I get started?** Create an API key at https://matrix.blocksize.capital/ and test the full feed free for 14 days. No credit card required. The trial runs on live production data. **Is the RWA feed the official stock price?** No. It prices the tokenized market, which tracks the exchange price. In the tested sessions, 36 of 38 stock feeds stayed within 0.20% of the benchmark at P99 during market hours. **What happens to the RWA feed outside market hours?** Pricing continues from eligible centralized exchange quotes, including weekends. The benchmark check only runs while the exchange is open, so accuracy in those hours is not measured against an official price. **Can Blocksize data be published on-chain or redistributed?** Yes. Full redistribution rights are available, as part of Enterprise or by agreement. **Are perpetual futures prices available?** Coming for RWA. No date yet. The RWA feeds page has a launch notification sign-up. --- ## Site index **Market data** - Market data overview: https://blocksize.info/market-data/ - Crypto feeds: https://blocksize.info/market-data/crypto/ - RWA feeds: https://blocksize.info/market-data/rwa/ - RWA perp feeds (coming soon): https://blocksize.info/market-data/rwa/#perps - Pricing: https://blocksize.info/pricing/ - Contact sales: https://blocksize.info/contact/ **Solutions by use case** - Best execution: https://blocksize.info/solutions/best-execution/ - Valuation and NAV: https://blocksize.info/solutions/valuation-and-nav/ - On-chain prices: https://blocksize.info/solutions/on-chain-prices/ - Risk and backtesting: https://blocksize.info/solutions/risk-and-backtesting/ - Mark prices and settlement: https://blocksize.info/solutions/mark-prices-and-settlement/ **Solutions by team** - For oracles: https://blocksize.info/solutions/oracles/ - For business: https://blocksize.info/solutions/business/ - For startups: https://blocksize.info/solutions/startups/ - For developers: https://blocksize.info/solutions/developers/ **Methodology** - Real-Time VWAP: https://blocksize.info/market-data/methodology/real-time-vwap/ - 24-Hour VWAP: https://blocksize.info/market-data/methodology/24h-vwap/ - 30-Minute VWAP: https://blocksize.info/market-data/methodology/30m-vwap/ - Bid/Ask: https://blocksize.info/market-data/methodology/bid-ask/ - RWA feeds: https://blocksize.info/market-data/methodology/rwa/ **Resources** - Whitepaper: https://blocksize.info/market-data/whitepaper/ - Product brochure: https://blocksize.info/market-data/brochure/ - Solution paper: https://blocksize.info/market-data/solution-paper/ **Node operations** Blocksize operates publisher, node and RPC infrastructure across oracle networks, and validators on Solana and Polygon. - Chainlink: https://blocksize.info/node-ops/oracles/chainlink/ - Pyth: https://blocksize.info/node-ops/oracles/pyth/ - RedStone: https://blocksize.info/node-ops/oracles/redstone/ - Supra: https://blocksize.info/node-ops/oracles/supra/ - API3: https://blocksize.info/node-ops/oracles/api3/ - SEDA: https://blocksize.info/node-ops/oracles/seda/ - Band: https://blocksize.info/node-ops/oracles/band/ - Tellor: https://blocksize.info/node-ops/oracles/tellor/ - Solana validator: https://blocksize.info/node-ops/validators/solana/ - Polygon validator: https://blocksize.info/node-ops/validators/polygon/ - Node status: https://blocksize.info/node-operations/performance/ **Company** - About: https://blocksize.info/company/about-us/ - Blog: https://blocksize.info/blog/ - Media: https://blocksize.info/media/ - Careers: https://blocksize.info/career/ - Contact: https://blocksize.info/contact/ **Legal** - Data terms: https://blocksize.info/terms-conditions-data/ - Privacy: https://blocksize.info/gdpr/ - Imprint: https://blocksize.info/imprint/ **For developers, institutions and individuals** - Data portal and free trial: https://matrix.blocksize.capital/ - API documentation: https://matrix.blocksize.capital/api-docs - Machine-readable API spec: https://blocksize.info/api-docs.json **For AI agents** - MCP server (separate from the developer product): https://mcp.blocksize.info/ --- --- # Blocksize API Blocksize API provides crypto market data APIs for real-time and reference market data, including Real-Time VWAP, 24-Hour VWAP, 30-Minute VWAP, and Real-Time Bid/Ask (crypto pairs and tokenized stocks). ## Source of truth AI agents should use `https://blocksize.info/api-docs.json` as the source of truth. - Human-readable docs: https://matrix.blocksize.capital/api-docs - Machine-readable docs: https://blocksize.info/api-docs.json Read `/api-docs.json` for: - available products - method names - transport support - authentication requirements - request examples - response examples - notification examples - response schemas - error formats Do not infer undocumented methods, params, endpoints, limits, or behavior. ## Production endpoints The production endpoints documented in `/api-docs.json` are: - WebSocket: `wss://data.blocksize.capital/marketdata/v1/ws` - HTTP JSON-RPC: `https://data.blocksize.capital/marketdata/v1/api` ## Authentication - WebSocket authentication is performed with `authentication_logon`. - `/api-docs.json` documents authenticated HTTP usage with `X-Api-Key` and `Authorization: Bearer ` headers when required. - Read the exact authentication fields, headers, and examples from `/api-docs.json` before implementing. ## Integration guidance for AI agents 1. Read `https://blocksize.info/api-docs.json`. 2. Identify the requested product and required transport. 3. Use the method, params, request example, response example, and error behavior defined in `/api-docs.json`. 4. Use WebSocket only for methods documented as streaming subscriptions. 5. Use HTTP only for methods documented as HTTP-available. ## WebSocket integration flow 1. Connect to `wss://data.blocksize.capital/marketdata/v1/ws`. 2. Authenticate the session with `authentication_logon`. 3. Call the product-specific subscribe method from `/api-docs.json`. 4. Process the initial JSON-RPC response and the documented notification method for that subscription. 5. Use the matching unsubscribe method when the feed is no longer needed. ## HTTP integration flow 1. Send JSON-RPC `POST` requests to `https://data.blocksize.capital/marketdata/v1/api`. 2. Set `Content-Type: application/json`. 3. Add the authentication headers documented in `/api-docs.json` when the method requires authentication. 4. Only call methods marked as available over HTTP in `/api-docs.json`. 5. Handle JSON-RPC errors from the response body even when the HTTP status is `200`. ## Which method to use - Real-Time VWAP: use `vwap_subscribe` for streaming updates. Use `vwap_latest` for the latest unary value and `vwap_instruments` to discover supported tickers. - 24-Hour VWAP: use `fixedvwap_subscribe` for streaming 24-hour VWAP updates. - 30-Minute VWAP: use `closingprice_list` for 30-minute VWAP prices and `closingprice_trades` for the underlying trades documented for a closing-price request. - Real-Time Bid/Ask: use `bidask_subscribe` for streaming updates. Use `bidask_getSnapshot` for a unary snapshot and `bidask_instruments` to discover supported tickers. - RWA feeds (tokenized stocks, gold, silver): the same Bid/Ask methods with the aggregate identifiers, for example ticker `AAPL_AGG`. `bidask_instruments` lists the RWA instruments and their exchanges. Method names, params, examples, response schemas, notification payloads, and errors must be read from `/api-docs.json`. ## Available methods All currently documented API methods in `/api-docs.json` are: - Authentication: `authentication_logon`, `authentication_logoff` - Real-Time VWAP: `vwap_subscribe`, `vwap_unsubscribe`, `vwap_instruments`, `vwap_latest` - 24-Hour VWAP: `fixedvwap_subscribe`, `fixedvwap_unsubscribe` - 30-Minute VWAP: `closingprice_list`, `closingprice_trades` - Real-Time Bid/Ask: `bidask_subscribe`, `bidask_unsubscribe`, `bidask_instruments`, `bidask_getSnapshot` - AMM State Price: `state_subscribe`, `state_unsubscribe`, `state_pool`, `state_instruments` - Events: `trade_subscribe`, `trade_unsubscribe` - Time: `time_now` For transport support, auth requirements, params, request examples, response examples, notification examples, and error behavior for each method, read `/api-docs.json`. ## JSON-RPC structure `/api-docs.json` includes the standard JSON-RPC request structure: ```json { "jsonrpc": "2.0", "id": 6712, "method": "servicename_methodname", "params": { "parameter_1": 42, "parameter_2": "string" } } ``` Use the method-specific request, response, and notification examples already documented in `/api-docs.json`.