{"id":2731,"date":"2026-07-06T19:40:18","date_gmt":"2026-07-06T23:40:18","guid":{"rendered":"https:\/\/vezgo.com\/blog\/?p=2731"},"modified":"2026-07-06T19:40:59","modified_gmt":"2026-07-06T23:40:59","slug":"open-finance-stack-bank-investment-crypto-data","status":"publish","type":"post","link":"https:\/\/vezgo.com\/blog\/open-finance-stack-bank-investment-crypto-data\/","title":{"rendered":"The Open Finance Stack: How Bank, Investment, and Crypto Data Connect"},"content":{"rendered":"
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The open finance stack is the infrastructure layer that lets a single application read a user’s bank balance, investment positions, and crypto holdings in one request flow. Understanding how that infrastructure works (how each type of connection is authenticated, how data from incompatible systems gets normalized, and where the real engineering challenges lie) matters whether you are building a product on top of it or evaluating one that already does. <\/p>\n\n\n\n

This article explains the mechanics: how bank, investment, and crypto data sources connect differently, why normalization is harder than it sounds, what the authentication flows look like, and where platforms like Vezgo sit in that stack.<\/p>\n\n\n\n

What Is the Open Finance Stack and Why Does It Matter?<\/h2>\n\n\n\n

The open finance stack is not a single technology but a combination of three distinct connection types that each work differently, operate under different regulatory frameworks, and present different engineering challenges. Treating them as equivalent leads to integration decisions that create problems later. The three layers are banking data, investment data, and crypto data, and the stack’s job is to connect all three, normalize them into a common schema, and make them available through a consistent developer interface.<\/p>\n\n\n\n

For years, financial services operated in separate environments. A bank knew about cash balances. A brokerage tracked stocks and exchange-traded funds. A crypto exchange managed digital asset holdings. People had to log into multiple platforms to understand their complete financial position. The open finance stack creates the bridge between those environments, transforming fragmented data into a complete financial picture that benefits consumers, fintech companies, wealth managers, and enterprise organizations alike.<\/p>\n\n\n\n

How Each Data Layer Actually Works<\/h2>\n\n\n\n

Each of the three data layers in the open finance stack connects through a different mechanism, operates under a different regulatory framework, and presents a different set of engineering challenges. Understanding those differences before building is what prevents the integration mistakes that are expensive to fix later.<\/p>\n\n\n\n

Banking Data: Regulated and Standardized<\/h3>\n\n\n\n

Bank data connectivity in the UK and EU is governed by open banking regulations that mandate banks expose standardized APIs to licensed third parties. In the UK, the CMA’s 2017 Retail Banking Market Investigation Order<\/a> forced the nine largest banks to open their APIs, creating Account Information Service Providers (AISPs) who can read account data and Payment Initiation Service Providers (PISPs) who can move money. The EU’s equivalent is PSD2.<\/p>\n\n\n\n

The connection flow works like this: a user authenticates with their bank through the bank’s own interface, the bank issues a token to the licensed third party, and that token grants scoped, time-limited read access to specific account data. Your application never sees the user’s bank credentials. OAuth 2.0 underpins most of these flows, and what comes back is a standardized data structure covering balances, transaction history, and account metadata. The US equivalent, Section 1033 under Dodd-Frank, exists as legislation but is currently enjoined and not enforced<\/a>, meaning US bank connectivity relies more on industry agreements and workarounds than on a mandated API standard.<\/p>\n\n\n\n

Investment Data: Less Standardized, More Variable<\/h3>\n\n\n\n

Investment data connections cover brokerage accounts, retirement accounts, and securities holdings, and unlike banking there is no single regulatory mandate requiring brokerages to expose APIs in the same way PSD2 requires banks. Connections typically happen through one of three mechanisms: OAuth-based API access where the brokerage supports it, credential-based connections where the user provides their login, or data export integrations that pull from CSV or FIX-format feeds.<\/p>\n\n\n\n

The variability creates normalization challenges. A holding at one brokerage and a holding at another will be described in different data structures with different field names, different ways of representing corporate actions, and different approaches to cost basis. Every investment data connection your stack supports adds its own normalization burden.<\/p>\n\n\n\n

Crypto Data: Technically Different from Both<\/h3>\n\n\n\n

Crypto data is the most technically distinct layer, and it is where most open finance integrations underestimate complexity. Crypto data comes from two structurally different sources that require different connection approaches.<\/p>\n\n\n\n

For centralized exchanges, the connection resembles investment data: a user generates an API key inside their exchange account, grants read-only access, and a third party uses that key to query balance and transaction endpoints. Each exchange has its own API structure, rate limits, authentication methods, and data schemas. Aggregating across exchanges means handling dozens of incompatible APIs simultaneously.<\/p>\n\n\n\n

For on-chain wallets and DeFi, the connection is entirely different. Blockchain data is publicly readable, but making it usable requires reading from multiple blockchain nodes across different networks, decoding transaction data that arrives in raw hexadecimal format, resolving token contract addresses to human-readable names and prices, and understanding protocol-specific logic for DeFi positions. <\/p>\n\n\n\n

A liquidity pool position on Uniswap v3 does not appear as a simple balance; it is encoded in a smart contract that has to be queried and decoded to understand the user’s actual holdings. This is why crypto data aggregation is a harder engineering problem than banking aggregation: the sources are more numerous, less standardized, and structurally more varied.<\/p>\n\n\n\n

The Normalization Problem: Why Standardization Is the Hard Part<\/h2>\n\n\n\n

Normalization is where most of the real engineering complexity in an open finance stack lives. Once data arrives from banking, investment, and crypto sources, it exists in incompatible formats, and defining a common schema and transforming every source’s native structure into it is not a trivial problem.<\/p>\n\n\n\n

A “transaction” at a bank is a debit or credit with a merchant name and amount. A “transaction” at a crypto exchange might be a spot trade, a transfer, a fee, a staking reward, or a liquidation event. A DeFi transaction can involve multiple token swaps, protocol fees, and position changes all bundled into a single on-chain event. Normalization means answering questions like: how is cost basis calculated for a swap on Uniswap versus a purchase on Coinbase? How is a staking reward categorized for tax purposes? When a user moves assets from an exchange to a self-custody wallet, how is that transfer matched across two separate data sources?<\/p>\n\n\n\n

These are not trivial decisions, and every platform makes them differently. The open finance stack you build on inherits those decisions, which is why the normalization choices of an aggregation provider matter significantly to the quality of the product built on top of it.<\/p>\n\n\n\n

Authentication and Consent: The Security Layer<\/h2>\n\n\n\n

The security architecture of an open finance stack solves a specific problem: how do you let an application access sensitive financial data without exposing the user’s credentials to that application? Each layer solves it differently.<\/p>\n\n\n\n

For regulated bank data under PSD2 and open banking, the answer is OAuth 2.0 with PKCE and Strong Customer Authentication, which typically means two-factor authentication at the bank level. The user authenticates directly with their bank; your application receives a token, not a password. For crypto CEX connections, the equivalent is API key authentication with scoped permissions. A well-implemented CEX integration uses read-only API keys that the user generates explicitly, cannot initiate withdrawals, and can be revoked at any time from the exchange’s interface.<\/p>\n\n\n\n

For on-chain data, there is no authentication in the traditional sense because the data is public. The consent element for on-chain data is the user providing their wallet address, and the open finance stack’s job is verification: confirming the user actually controls the wallet through a signed message challenge rather than just knowing its address. Across all three layers, consent management (tracking what permissions have been granted, to whom, and for how long, and providing a clear revocation mechanism) is a user trust problem as much as a technical one.<\/p>\n\n\n\n

Why the Crypto Layer Changes the Economics of Open Finance<\/h2>\n\n\n\n

The crypto layer makes the open finance stack significantly more complex to build and maintain, but it also makes the business case for aggregation significantly stronger. Before crypto, the main argument for aggregation was convenience: instead of logging into three bank accounts and a brokerage, see everything in one place. With crypto, the argument becomes structural necessity.<\/p>\n\n\n\n

A user with assets across four exchanges, two self-custody wallets, a staking position, and a DeFi liquidity pool cannot realistically maintain an accurate picture of their holdings without aggregation. The data is too fragmented and too technical for manual reconciliation to be reliable. This is what drives institutional demand: crypto hedge funds<\/a> and asset managers increasingly need reporting tools that combine traditional finance records with blockchain activity, not as a convenience feature but because accurate position reporting requires it.<\/p>\n\n\n\n

It also drives compliance demand. Source and destination of funds analysis in crypto<\/a> requires complete, reconciled transaction histories across all the wallets and exchanges where a user’s assets have moved. Wallet risk scoring<\/a> depends on the same underlying data. Digital asset auditing<\/a> requires verifiable records that connect on-chain activity to off-chain accounting entries. None of these functions are possible without reliable aggregated data.<\/p>\n\n\n\n

The Regulatory Context Shaping the Stack<\/h2>\n\n\n\n

Two EU regulations are defining the future structure of the open finance stack in Europe, and understanding where each one stands matters for any product built in or for EU markets.<\/p>\n\n\n\n

PSD2 already mandates bank data sharing across the EU and has driven the open banking ecosystem that now has over 16 million active users in the UK alone. It covers payment accounts but not investment or crypto data. The proposed Financial Data Access Regulation (FiDA)<\/a> would extend PSD2-style mandatory data sharing to investments, pensions, insurance, and explicitly names crypto assets as an in-scope data category. FiDA is still in trilogue negotiations as of mid-2026, with first-phase implementation expected in 2027 at the earliest. When it takes effect, it will formally bring the crypto data layer into the same regulated data-sharing framework that banking data already operates under.<\/p>\n\n\n\n

Outside the EU, the regulatory picture is less settled. In the US, Section 1033 exists as legislation but is not currently enforced. In Canada, the Consumer-Driven Banking Act establishes oversight but the operational system is not yet live. The practical implication: products built for UK and EU markets can rely on regulated API access for banking data today; products built for other markets often rely on a combination of industry agreements, API keys, and credential-based connections with varying levels of standardization. For crypto-specific obligations, the EU’s Markets in Crypto-Assets Regulation (MiCA)<\/a> governs how crypto-asset service providers must operate, setting unified licensing and transparency requirements across all 27 member states.<\/p>\n\n\n\n

Where Vezgo Fits in the Stack<\/h2>\n\n\n\n

Vezgo operates at the crypto layer, handling the CEX connection problem, the wallet connection problem, and the normalization problem so development teams do not have to. Its crypto data API<\/a> covers OAuth and API key flows across 40+ exchanges, on-chain balance and transaction retrieval across 20 blockchains and 250 wallets, and a consistent data schema regardless of source. This lets teams building portfolio trackers<\/a>, tax tools, and wealth management dashboards work from a single integration rather than maintaining separate connections for every exchange and blockchain their users might use.<\/p>\n\n\n\n

The compliance-sensitive side matters specifically for institutional and regulated products. Vezgo holds SOC 2 Type 2 certification, complies with GDPR and PIPEDA, and uses AES-256 encryption, meaning its security architecture<\/a> meets the documented standard that institutional clients and regulators ask for in a vendor audit. For products that extend into compliance workflows, the same aggregated data underpins risk dashboards and analytics in crypto compliance<\/a>, as well as tax and accounting<\/a> workflows that require complete, reconciled transaction histories.<\/p>\n\n\n\n

What a Complete Open Finance Stack Enables<\/h2>\n\n\n\n

A complete open finance stack, with banking, investment, and crypto layers connected and normalized, enables a category of product that does not work without all three. Each missing layer produces a partial answer that could lead to a bad financial decision.<\/p>\n\n\n\n

A wealth management platform for a client with stocks, bonds, and crypto holdings needs all three to produce an accurate net worth figure, a realistic asset allocation, and a tax liability estimate. A lending platform that wants to accept crypto as collateral needs the crypto layer to assess what the borrower actually holds and verify ownership, the banking layer to verify income and cash flow, and the investment layer to understand overall wealth context. Each layer is necessary for a complete credit picture, which is what makes products like crypto-backed mortgages<\/a> technically viable at institutional scale.<\/p>\n\n\n\n

A crypto compliance tool performing source and destination of funds analysis<\/a> needs the crypto layer to trace on-chain movements but needs the banking layer to connect those movements to fiat entry and exit points. Without the connection between the two, the analysis is incomplete regardless of how sophisticated the on-chain tracing is.<\/p>\n\n\n\n

The Infrastructure Bet Behind Open Finance<\/h2>\n\n\n\n

Building on the open finance stack is a bet that financial data connectivity will continue to expand, that regulatory frameworks will increasingly mandate the access your product depends on, and that users will increasingly expect their financial tools to work together rather than separately. That bet looks well-supported.<\/p>\n\n\n\n

Open banking is live and growing in the UK and EU, with measurable economic impact<\/a>: analysis commissioned by Open Banking Limited and conducted by EY estimates UK open banking has delivered \u00a38.3 billion in cumulative economic benefit, with long-term annual potential reaching up to \u00a343 billion at full maturity. FiDA will extend the same framework to investment and crypto data. Institutional crypto adoption, documented in the big firms crypto investment policies<\/a> now common across asset managers and corporate treasuries, has made integrated financial data a business requirement. And the tools for building on this stack have matured significantly, particularly on the crypto aggregation side where the hardest normalization and connectivity problems are now solved at the infrastructure layer rather than in every application built on top.<\/p>\n\n\n\n

The open finance stack is not a future concept. It is infrastructure being built now, and the products built on it are already defining what integrated financial services look like.<\/p>\n\n\n\n

Frequently Asked Questions<\/h2>\n\n\n\n

The open finance stack covers a lot of ground, and the questions developers and product teams tend to ask often come down to a few practical concerns. Here are direct answers to the most common ones.<\/p>\n\n\n\n

What is the difference between open banking and open finance?<\/h3>\n\n\n\n

Open banking is a specific, regulated subset of open finance covering payment account data (bank balances and transaction history) mandated by frameworks like PSD2 in the EU and the CMA’s open banking order in the UK. Open finance extends the same data-sharing principles to a broader set of financial products including investments, pensions, insurance, and crypto assets. Open banking is live and enforced in several markets today; open finance is still being formalized, most concretely through the EU’s FiDA proposal, which is currently in trilogue negotiations.<\/p>\n\n\n\n

Why is crypto data harder to aggregate than bank data?<\/h3>\n\n\n\n

Bank data comes from institutions that are regulated to expose standardized APIs, which means the connection flow and data structure are relatively predictable. Crypto data comes from two structurally different sources: centralized exchanges, each with their own incompatible API, and public blockchains, where transaction data arrives in raw hexadecimal format that has to be decoded and enriched before it is usable. DeFi positions add another layer of complexity because they are encoded inside smart contracts that require protocol-specific queries to interpret. The result is that aggregating crypto data from ten sources is a harder engineering problem than aggregating bank data from ten banks.<\/p>\n\n\n\n

Is the open finance stack something that exists today or still theoretical?<\/h3>\n\n\n\n

The banking and crypto layers exist and are in production today. Open banking APIs are live in the UK and EU, and crypto aggregation APIs like Vezgo already normalize data across 40+ exchanges, 20 blockchains, and 250 wallets into a consistent schema. The investment layer is less standardized and more variable depending on brokerage. The regulatory framework for the full stack, covering investment, insurance, pension, and crypto data under a single mandate, is still being built; the EU’s FiDA proposal is the most advanced attempt, with implementation expected from 2027 onwards.<\/p>\n\n\n\n

What is data normalization and why does it matter for open finance products?<\/h3>\n\n\n\n

Data normalization is the process of converting financial data from many different source formats into a single consistent schema that your application can reliably process. It matters because every exchange, bank, and blockchain describes the same concepts differently. A transaction on Binance and a transaction from a self-custody wallet arrive in completely different structures with different field names, different ways of categorizing the event type, and different approaches to fees. Without normalization, your application has to handle every source’s quirks separately. With it, a transaction is always a transaction regardless of where it came from. The normalization choices made at the aggregation layer flow downstream into the quality and reliability of every product built on top of it.<\/p>\n\n\n\n

What regulations govern how open finance data can be accessed and shared?<\/h3>\n\n\n\n

The specific regulations depend on geography and data type. In the UK and EU, PSD2 governs bank account data sharing and is already in force. The EU’s FiDA proposal would extend mandatory data-sharing rules to investment, pension, insurance, and crypto data, but is still in negotiation as of mid-2026. In the US, Section 1033 under Dodd-Frank exists as legislation but is currently enjoined. In Canada, the Consumer-Driven Banking Act establishes oversight for open banking but the system is not yet operational. For crypto-specific compliance requirements, the EU’s MiCA regulation governs how crypto-asset service providers must operate and what data obligations they carry.<\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"

The open finance stack is the infrastructure layer that lets a single application read a user’s bank balance, investment positions, and crypto holdings in one request flow. Understanding how that infrastructure works (how each type of connection is authenticated, how data from incompatible systems gets normalized, and where the real engineering challenges lie) matters whether […]<\/p>\n","protected":false},"author":5,"featured_media":2732,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[167],"tags":[],"class_list":["post-2731","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-open-banking"],"_links":{"self":[{"href":"https:\/\/vezgo.com\/blog\/wp-json\/wp\/v2\/posts\/2731","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vezgo.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vezgo.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vezgo.com\/blog\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/vezgo.com\/blog\/wp-json\/wp\/v2\/comments?post=2731"}],"version-history":[{"count":1,"href":"https:\/\/vezgo.com\/blog\/wp-json\/wp\/v2\/posts\/2731\/revisions"}],"predecessor-version":[{"id":2733,"href":"https:\/\/vezgo.com\/blog\/wp-json\/wp\/v2\/posts\/2731\/revisions\/2733"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vezgo.com\/blog\/wp-json\/wp\/v2\/media\/2732"}],"wp:attachment":[{"href":"https:\/\/vezgo.com\/blog\/wp-json\/wp\/v2\/media?parent=2731"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vezgo.com\/blog\/wp-json\/wp\/v2\/categories?post=2731"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vezgo.com\/blog\/wp-json\/wp\/v2\/tags?post=2731"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}