Level 1 vs Level 2 Stock Market Data: What Your Trading App Really Needs

 

Whether you're building a trading dashboard, a portfolio analytics tool, or a high-frequency trading bot, the kind of stock market data you use will define what your users can see—and how fast they can act. While many developers start with Level 1 data because it's easier to integrate and generally cheaper, others quickly realize they need more depth. That’s where Level 2 stock data comes in.

But what exactly is the difference between Level 1 and Level 2 data? When should you use one over the other? And how do you integrate them into your app without overengineering the solution?

This post will break down what each level includes, how it impacts trading performance, and how to choose the right market data for your product. Whether you're a fintech founder, a developer, or a product lead, understanding this distinction will help you avoid overpaying—or underbuilding.

Looking to integrate real-time order book data? We’ll also cover how to access both data levels using Finage APIs.

 

Table of Contents

- What Is Level 1 Market Data?

- What Is Level 2 Market Data?

- Key Differences That Affect Your Users

- Use Cases: When to Choose Level 1 vs Level 2

- Real-Time Access via Finage APIs

- Implementation Tips and Developer Considerations-Final Thoughts: Building Data-Ready Apps

 

1. What Is Level 1 Market Data?

Level 1 market data gives you the most basic—but essential—view of trading activity for a stock. It’s typically the first type of data a developer or trading app uses because it provides real-time pricing at the surface level, without exposing the full depth of the market.

Here’s what Level 1 data usually includes:

- Last traded price: The most recent execution price for a given stock.

- Bid and ask prices: The highest price someone is willing to buy (bid), and the lowest price someone is willing to sell (ask).

- Bid and ask sizes: The volume of shares available at the current bid and ask.

- Volume: The total number of shares traded over the current day.

- Open, high, low, close (OHLC): Snapshot data for charting and historical analysis.

Level 1 data is used in:

- Real-time price charts

- Watchlists

- Alerts for price movement

- Portfolio value tracking

- Simple order execution interfaces

It’s perfect when you only need top-of-book visibility and aren’t actively analyzing market depth. That’s why Level 1 feeds are often found in retail trading apps, investor dashboards, and basic charting platforms.

You can access Level 1 data for U.S. equities and global markets through Finage's Stock Data API, which provides clean, low-latency pricing information and accurate tick data for both delayed and real-time use cases.

If you’re just tracking price movement and current quotes, Level 1 may be all you need—but deeper insight requires more.

 

2. What Is Level 2 Market Data?

Level 2 market data—also known as market depth data—goes beyond the top-of-book prices shown in Level 1. It reveals the structure of the order book by listing multiple layers of bid and ask prices along with their respective volumes.

Level 2 gives you:

- Multiple bid and ask levels: Often the top 5–15 prices on each side of the book

- Order sizes at each price level: Volume data associated with every tier

- Market participant information (optional): In some markets, you can see who placed the order (e.g., market maker IDs)

- Real-time updates: As orders are placed, modified, or canceled, the book changes live

This data is essential for:

- Algorithmic and high-frequency trading (HFT)

- Estimating slippage or market impact before placing large trades

- Visualizing supply and demand depth

- Detecting spoofing or unusual market activity

- Smart order routing

For developers, integrating Level 2 data means handling a much higher volume of updates. You’re not just reacting to trades—you’re reacting to the entire flow of orders entering and exiting the book.

Finage offers access to Level 2 stock market data via both REST and WebSocket APIs, enabling real-time order book tracking across supported exchanges.

If your users care about liquidity, execution quality, or short-term price prediction, Level 2 data can be a game-changer.

 

3. Key Differences That Affect Your Users

Choosing between Level 1 and Level 2 stock data isn’t just a technical decision—it directly shapes the experience and expectations of your users. From pricing to insight depth, each data level serves different needs.

Here’s how they compare:

Feature	Level 1	Level 2
Bid/Ask visibility	Best (top) bid and ask only	Multiple price levels across both sides
Order book depth	Not visible	Fully visible (up to 15+ tiers)
Data volume	Lower	Significantly higher (many updates/sec)
Use case	Retail trading, price tracking	Pro trading, execution engines, dashboards
Complexity	Simple to implement and display	Requires normalization, real-time updates
Cost	Lower data licensing fees	Higher due to market depth licensing

For retail users or long-term investors, Level 1 often feels fast and responsive enough. But for active traders, the ability to see order flow—where liquidity is moving, where walls are forming, or when the book is thinning—is critical.

If you're building:

- A mobile investing app → Level 1 likely covers your needs.

- A real-time trading terminal → You’ll need Level 2 for full market context.

- Execution intelligence tools or risk dashboards → Level 2 is essential.

Finage supports both levels through their stock data APIs, so you can start with Level 1 and scale into Level 2 as your product matures.

 

4. Use Cases — When to Choose Level 1 vs Level 2

Choosing between Level 1 and Level 2 data depends on who your users are and what decisions they need to make inside your app. Each level has strengths—it's not about which is better, but which is right for your use case.

When Level 1 is Enough

- Portfolio tracking apps: When you only need current price, volume, and basic metrics.

- Watchlists and alerts: Trigger notifications based on price or daily performance.

- Educational or beginner tools: For users new to trading, Level 1 keeps the UI clean.

- Retail broker apps: Many brokerage platforms use Level 1 for basic order interfaces.

Level 1 is also ideal for building fast-loading dashboards, pricing APIs, and low-maintenance tools that require less backend complexity.

When Level 2 is Essential

- Real-time trading platforms: Especially for day trading or scalping strategies.

- Execution algorithms: Bots that need to route or size trades based on liquidity depth.

- Market analytics dashboards: Tools that visualize liquidity, order flow, or trade imbalances.

- Risk management engines: Systems that monitor liquidity risk across multiple assets.

If your users care about what’s behind the current price—or if your product needs to anticipate price shifts before they occur—then Level 2 is the right choice.

You can start testing both through Finage's stock API endpoints, scaling between real-time REST data and WebSocket feeds as your user base grows.

 

5. Real-Time Access via Finage APIs

Accessing Level 1 and Level 2 data in real time is critical for delivering a responsive trading experience. With Finage, developers get scalable access to both data levels through well-documented REST and WebSocket APIs, designed to support everything from lightweight dashboards to enterprise-grade trading systems.

Level 1 data endpoints offer fast, clean access to live pricing, bid/ask values, volume, and historical charts. These are ideal for use cases where surface-level visibility is enough, such as watchlists, price alerts, or portfolio tracking.

In contrast, Level 2 data from Finage reveals the full depth of the order book. It includes multiple price levels for bids and asks, giving your application a detailed view of market liquidity. This becomes essential when your product needs to show order flow in real time or guide execution strategies.

Both data types are accessible through Finage’s stock API documentation, which outlines request parameters, subscription methods, and response formats. You can start with REST for simpler integrations, or move to WebSocket streams for faster and more efficient data delivery.

Because Finage separates pricing tiers by data level, you can design your product architecture modularly, starting with Level 1 and integrating Level 2 only where performance justifies it.

Finage APIs are built to scale alongside your app’s needs, allowing you to add real-time depth without refactoring your entire data layer.

 

6. Implementation Tips and Developer Considerations

Adding market data to your application goes beyond accessing the API. It requires careful design to ensure performance, accuracy, and a seamless user experience—especially when working with Level 2 data.

For Level 1 integrations, implementation is relatively straightforward. You can typically call an endpoint or subscribe via WebSocket to receive price updates and apply them directly to charts, watchlists, or trading interfaces. Most platforms can handle this with minimal backend architecture, which is why Level 1 is often the default for early-stage products.

With Level 2 data, the stakes are different. You're dealing with a continuous stream of order book updates—sometimes dozens per second. To handle this effectively, you'll need to optimize how your frontend consumes and visualizes data. That includes throttling updates, caching intelligently, and maintaining order across updates to reflect true market depth.

Latency becomes another key concern. If your system introduces even slight delays, users may see outdated bid/ask levels or make decisions based on stale data. Using WebSocket APIs from Finage helps reduce this risk, as the data arrives in near real-time and is already structured for live streaming environments.

Another factor is data normalization. Different exchanges may represent depth data in slightly different ways. Finage standardizes this across supported markets, which simplifies the process of building multi-exchange or global dashboards.

Finally, consider licensing and cost management. Since Level 2 data is often more expensive due to exchange fees and infrastructure overhead, you may choose to offer it as a premium feature, gating access by user tier or usage volume.

 

7. Final Thoughts — Building Data-Ready Apps

The difference between a good trading app and a great one often comes down to the data it’s built on. Choosing between Level 1 and Level 2 market data isn’t just a backend decision—it shapes how your users interact with the market, how confident they feel in their trades, and how your product is perceived.

Level 1 offers speed, simplicity, and broad accessibility—ideal for many retail-focused tools or early-stage platforms. But when your users demand precision, visibility into liquidity, or advanced execution tools, Level 2 becomes essential. It opens up a deeper layer of market behavior that enables more informed decision-making.

Finage makes this transition smooth by offering both data types through reliable, developer-friendly APIs. Whether you're building a basic price tracker or a professional-grade trading terminal, Finage helps you access the data that fits—scaling with your needs and infrastructure.

You can start exploring real-time quotes via the Stock Data API or access full order book visibility with Level 2 data endpoints. For low-latency applications, the WebSocket integration guide is your go-to resource.

And if you're still deciding what your app truly needs, this developer guide to market data architecture breaks down what to prioritize and why.

You can get your Real-Time and Historical Stocks Data with a Stock Data API key.

Build with us today!

Start Free Trial