Introduction to flAPI
flAPI is a high-performance serving layer that transforms your enterprise data systems—like Snowflake, BigQuery, or SAP—into fast, secure, AI-ready APIs. It acts as powerful middleware that decouples slow, expensive backend systems from the high-throughput demands of modern applications and AI agents.
The Problem: Data Warehouses Aren't API Servers
Traditional data warehouses and ERPs excel at analytical workloads but struggle with the demands of modern applications:
- High Latency: Queries take seconds, not milliseconds
- Expensive: Every query costs money; high-frequency access gets expensive fast
- Not Designed for APIs: No built-in rate limiting, caching, or authentication
- Poor Concurrency: Can't handle hundreds of simultaneous API requests
- AI-Unfriendly: No structured tool interfaces for AI agents
Applications and AI agents need fast, frequent access to data. Querying warehouses directly is both slow and expensive.
The Solution: A High-Performance Serving Layer
flAPI solves this by sitting between your slow backends and fast consumers:
How It Works
- Connect: Point flAPI to your data sources (BigQuery, Snowflake, Parquet, etc.)
- Define: Write SQL templates and configure endpoints in simple YAML files
- Serve: flAPI materializes a fast, local cache using DuckDB and serves APIs at millisecond latency
The cache absorbs high-frequency queries, dramatically reducing warehouse costs while providing the speed modern applications demand.
Key Benefits
🚀 Performance
Millisecond API responses vs. seconds for direct warehouse queries. Your applications feel instant.
💰 Cost Reduction
Reduce warehouse query costs by 90%+ by serving from cache. One expensive query refreshes data for thousands of API calls.
🤖 AI-Native
Built-in Model Context Protocol (MCP) support. Expose SQL templates as structured tools for AI agents—no duplicate work.
🛠️ Developer Experience
Local-first development with powerful CLI (flapii) and VS Code integration. Test templates, validate configs, debug queries—all locally.
🔒 Enterprise Security
JWT authentication, row-level security, rate limiting, and fine-grained access control out of the box.
📦 Simple Deployment
Single binary, zero dependencies. Deploy anywhere: AWS Lambda, Cloud Run, Kubernetes, or on-premise.
Core Features
Declarative API Configuration
Define endpoints, parameters, and security rules in simple YAML files. No code required.
Full CRUD Support
Create, read, update, and delete endpoints with built-in validation, transactions, and RETURNING clauses. Write data safely with pre-write validation and ACID guarantees.
SQL as a Transformation Layer
Use the full power of SQL to transform and shape data. flAPI makes it easy to perform significant transformations right in the template.
Dynamic Templates with Mustache
Create flexible, reusable SQL queries with Mustache syntax—familiar to anyone who's used dbt.
DuckDB-Powered Caching
Strategic caching that's not just for speed—it's for cost optimization. Materialize high-value data locally and refresh on your schedule. Write operations update both cache and backend seamlessly.
MCP for AI Agents
Automatically expose your SQL templates as tools that AI agents can call. One config creates both REST APIs and structured tools. Agents can now not just read data but also create, update, and delete records.
Automatic Documentation
OpenAPI (Swagger) documentation generated automatically from your endpoint configs.
Who Is flAPI For?
Data Engineers
Build data APIs in minutes, not weeks. Focus on data transformation, not API boilerplate.
Backend Developers
Decouple applications from slow data sources. Get the speed you need without rewriting queries.
AI/ML Teams
Give your agents structured access to enterprise data through MCP. No custom integrations required.
Platform Teams
Provide a standardized way for teams to expose data as APIs with built-in governance and security.
Real-World Use Cases
- Analytics APIs: Serve dashboards and reports without hammering your warehouse
- Operational APIs: Create order, customer, and inventory endpoints that update data directly in your warehouse
- AI Agent Tools: Let agents query enterprise data through structured interfaces AND modify records safely with validation
- Customer-Facing APIs: Provide fast data access in customer applications with form submissions and real-time updates
- Internal Tools: Power internal apps with fresh data without warehouse costs, with full read/write access
- Real-Time Reporting: Cache frequently-accessed reports and refresh on schedule
- Bidirectional Sync: Mobile apps and web clients update the cache, which syncs safely to your warehouse
Architecture Philosophy
flAPI embraces the "small data" philosophy: most applications don't need all your data, just the right slice of it. By materializing a fast, local cache of high-value data, flAPI makes "big data" feel small and fast.
Local-First Development
Modern hardware is powerful. Develop locally with the exact same software you ship to production. No cloud complexity during development.
Think Small, Ship Joyfully
The entire workflow is optimized for rapid iteration. Define your API, run flapi, and test it instantly. This tight feedback loop makes development a joy.
Optimized for Serverless
The same small footprint and millisecond startup time make flAPI perfect for cost-efficient serverless deployments.
Next Steps
Ready to get started?
- Quickstart Guide: Build your first API in 5 minutes
- How It Works: Understand the 3-step process
- Build a Complete CRUD API: Create, read, update, and delete endpoints
- Write Operations Reference: Validation, transactions, and RETURNING clauses
- Architecture Deep Dive: Technical details and performance
- Configuration Guide: Learn all configuration options
- Connect Data Sources: BigQuery, PostgreSQL, Parquet, SAP
- Deployment Guide: Deploy to production
Need help? Check out our GitHub Discussions or view our services page for enterprise support options.