REST API or Flat Files: Choosing the best crypto data access method

Your strategy is ready. Your models are tuned. Now comes the big question:

How do you feed them clean, reliable crypto data, daily or in bulk?

Do you opt for CSV files download via flat files for historical crypto exchange data?

Do you rely on a Crypto Data API like REST for real-time crypto order book access?

Or should your pipeline combine both for optimal order book data and scalability?

This guide breaks down the trade-offs between REST APIs and flat files for crypto data download, helping you make the right call for your technical, operational, and trading needs.

What’s the Difference?

Flat Files: Bulk crypto data download and CSV downloads

Flat files are ideal for large-scale crypto data downloads. These datasets come as structured CSV files compressed with Gzip, making them efficient for loading into cloud storage, databases, or machine learning pipelines. They’re handy when you need complete historical data from crypto exchanges or full order book snapshots.

Use Flat Files When You:

• Need multi-year backtesting datasets with order book data.
• Prefer reproducible files (same file = same result) for audits.
• Want full trade history for offline analysis.
• Need local storage for crypto exchange data without real-time queries.

Supported Data Types:

• Trades: Executed trade records.
• Quotes: Best bid/ask prices.
• Limit Book Data: Full crypto order book snapshots and incremental updates.
• OHLCV: Daily/hourly candlestick data (coming soon).

Perfect for ML pipelines, research, and initializing crypto data warehouses.

Preview a Sample File:

Accessing crypto exchange data and crypto order book via crypto data API

When your system needs live crypto exchange data, the CoinAPI Crypto Data API is your go-to solution for accessing order book data and real-time market feeds.

Use REST When You:

• Need live updates for trading bots or dashboards using crypto exchange data.
• Monitor markets across multiple crypto exchanges with crypto order book data.
• Pull crypto exchange data filtered by symbol, time, or venue.
• Perform lightweight, frequent queries for order book data.

REST API Supports:

• Real-time & historical trades.
• Streaming quotes across 380+ crypto exchanges.
• Order Book Snapshots: Best bid/ask levels and top-of-book crypto order book views.
• Exchange metadata and market status.

REST is best for real-time infrastructure, dashboards, and automated systems.

Who benefits most? Tailoring your data solution to your role

Choosing between flat files and the Crypto Data API isn’t just a technical decision; it’s a strategic one that impacts your team’s efficiency and success. Here’s how CoinAPI’s solutions address pain points for various professionals:

For Quant & Academic Researchers

Get reproducible, research-grade crypto data download – no more noisy feeds

Struggling with incomplete backtests or inconsistent crypto exchange data? Quant researchers need clean, historical crypto data that’s consistent and traceable.

Use Flat Files to:

• Backfill full-year tick datasets for BTC, ETH, or altcoins by crypto data download.
• Guarantee same file = same result for audits or peer-reviewed work.
• Eliminate schema drift with structured S3 access for crypto data

Use the REST API to:

• Pull daily candles for updated charts using the Crypto Data API.
• Sync quotes or OHLCV for validation experiments with crypto exchange data.

For Data Scientists & ML Engineers

Train ML models with granular historical crypto data

Data gaps and latency issues kill predictive accuracy. Whether training a deep learning model or building sentiment-driven signals, you need stable crypto data access.

Use Flat Files to:

• Download historical tick data for multi-month ML pipelines via Gzip-compressed CSV files.
• Feed models with quotes and trades in a consistent format. (Use the REST API for OHLCV data.)
• Avoid gaps that poison training data.

Use the REST API to:

• Validate signals in production with Crypto Data API.
• Ingest fresh crypto exchange data every hour/day for continuous learning.
• Automate using REST for daily updates and flat files for monthly backfills.

For Quant Desks & Hedge Funds

Order Book Data for Live Strategies

Alpha erodes fast; don’t let your data pipeline slow you down. Quant desks need historical depth and low-latency crypto exchange data.

Use Flat Files to:

• Initialize models with years of trades, quotes, and limit book data.
• Audit strategy behavior with replayable order book data.

Use the REST API to:

• Monitor spreads and liquidity in real time with Crypto Data API.
• Sync multi-asset dashboards across exchanges.

Speed matters: CoinAPI’s WebSocket latency is <100ms median across 380+ exchanges.

For Infrastructure & Backend Engineers

Scale Your Trading Infra with Reliable Crypto Data Download

Tired of patching broken feeds? You need tools that work across systems and volumes.

Use Flat Files to:

• Handle large-volume ingestion jobs via CSV files download without rate limits.
• Maintain audit trails with timestamped and reproducible crypto files.
• Eliminate bottlenecks with S3-compatible clients.

Use the REST API to:

• Build filtered, low-latency endpoints for high-frequency apps using Crypto Data API.
• Integrate WebSocket and REST streams for a hybrid infrastructure.
• Automate failover and freshness checks for crypto exchange data.

Tip: Build resilience by combining REST for real-time and flat files for fallback.

Latency for Crypto Exchange Data Access

In trading, latency is a competitive edge. If your pipeline adds milliseconds, you could lose alpha. Here’s how latency might impact your project:

REST API Latency Profile

• Typical latency: 100–200 milliseconds for small crypto data payloads.
• Larger requests: Slightly higher response times, but CoinAPI ensures fast first-byte-out performance.
• Infrastructure: CoinAPI’s global servers mitigate latency and rate limits for the Crypto Data API.

Best use cases:

• Accessing historical crypto exchange data.
• Data synchronization jobs tolerate sub-second delays.
• Account or metadata management.

Need Real-Time Performance?

For low-latency use cases (e.g., live execution, signal processing, or crypto order book monitoring), REST may not suffice.

Consider:

• WebSocket API: Sub-100ms median latencies for order book data.
• FIX API: Microsecond-level responsiveness for institutional trading.

These protocols deliver push-based, event-driven feeds, ideal for high-frequency systems.

Proven in Production: Real customer results

Leading crypto companies demonstrate exactly when each approach works best. CCi30 uses CoinAPI's REST API to "run their indexes in real-time to track various cryptocurrencies", a use case where flat files simply can't deliver.

SingAlliance confirms that "real-time data streaming is a game-changer" for their integration needs. Meanwhile, Bitcoin.tax has relied on CoinAPI's infrastructure since 2019, proving the enterprise reliability needed for scaled data operations.

The lesson? Choose REST for real-time precision, flat files for comprehensive analysis, or combine both strategically.

How to choose: Decision Checklist

Pro tips for scaling your pipeline

• Start with flat files to build your foundation. This gives you complete coverage.
• Switch to API once your system is live and needs continuous updates.
• Monitor freshness: stale data can lead to silent strategy drift.
• Automate with failovers: use REST as primary, flat files as fallback.

What the best teams do

The smartest quant firms and data teams use both:

• Flat files → to backfill years of data, or initialize models
• REST API → to keep strategies fresh, pipelines up-to-date, and dashboards live

CoinAPI offers both downloadable flat files and real-time access via the Market Data API.

OHLCV Aggregation: REST API vs Flat Files

REST is CoinAPI's primary method for accessing OHLCV (candlestick) data. Each REST API request targets a specific symbol on a specific exchange, making it ideal for real-time integrations, such as pulling live candles for dashboards or syncing select trading pairs. This targeted approach ensures low-latency access to crypto exchange data but does not support retrieving OHLCV data for an entire exchange in a single call.

Currently, CoinAPI does not offer OHLCV data through Flat Files. However, flat files remain a powerful option for other crypto data download needs, providing consolidated datasets for all trading pairs across exchanges via downloadable csv files. For OHLCV data, the Crypto Data API is your go-to solution for both historical and real-time crypto exchange data, with plans to potentially include OHLCV in Flat Files in the future.

TL;DR

There’s no one-size-fits-all method; it’s about the right tool for the right job. Use the Crypto Data API for selective, live, or historical OHLCV crypto data download. For bulk crypto order book or order book data, choose CSV files download via flat files for comprehensive coverage with minimal integration complexity.

Scale your pipeline now! Explore Flat Files or Market Data API. See Pricing.