Best Practices for Integrating a Modular FastAPI Backend with a React Frontend

Question

Best Practices for Integrating a Modular FastAPI Backend with a React Frontend

Priya Rai 0

Approach for Structuring FastAPI & React Integration

I am working on a RAG-based accelerator and planning the integration between FastAPI (backend) and React (frontend). My approach is as follows:

Modular Backend: Each individual component (data processing, retrieval, etc.) is placed in separate Python files, ensuring independent data flow.
FastAPI Collation: All these components are collated into a single FastAPI file, which acts as the main API layer.
Frontend API Handling: In the React frontend, we call the FastAPI endpoints via api.js, allowing input-output flow as per our use case. Only the required components are used in the current accelerator.
we are hosting our accelerator's Backend on Azure App Services and Frontend on Blob Storage + cdn.
Future Scalability: Later, if we build another accelerator, we can reuse other components from the existing FastAPI file in a new React project.

Questions:

Is this approach feasible for maintaining modularity and reusability?
Will calling multiple components from a single FastAPI file slow down the frontend performance due to API response time or latency issues?
Any suggestions on optimizing the frontend API handling to avoid unnecessary delays?

Laxman Reddy Revuri 5,400 Reputation points Microsoft External Staff Moderator

2025-04-04T05:04:38.04+00:00
Hi @Priya Rai
Yes, structuring FastAPI components into separate files ensures modularity, making it easier to manage, update, and reuse in future projects. Colleague them into a single FastAPI app for API exposure is a common best practice and supports scalability.
No, FastAPI is optimized for high-performance, concurrent request handling. However, performance may be affected if endpoints involve heavy computations or blocking tasks. To avoid delays, optimize queries, use async processing, and offload long-running tasks to background workers.

Use asynchronous API calls (async/await, Axios) to prevent UI blocking.

Implement caching (React Query, SWR) to reduce redundant requests.

Batch requests, when possible, to minimize network overhead.

Optimize request triggers (debouncing, throttling) for user input-driven queries.

Show loading indicators to improve user experience while fetching data.
Laxman Reddy Revuri 5,400 Reputation points Microsoft External Staff Moderator

2025-04-07T17:26:55.8866667+00:00

Hi @Priya Rai
We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.
Laxman Reddy Revuri 5,400 Reputation points Microsoft External Staff Moderator

2025-04-08T19:53:28.8233333+00:00

Hi @Priya Rai
We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.

Your answer

Laxman Reddy Revuri 5,400 Reputation points Microsoft External Staff Moderator

2025-04-04T05:04:38.04+00:00

Hi @Priya Rai
Yes, structuring FastAPI components into separate files ensures modularity, making it easier to manage, update, and reuse in future projects. Colleague them into a single FastAPI app for API exposure is a common best practice and supports scalability.
No, FastAPI is optimized for high-performance, concurrent request handling. However, performance may be affected if endpoints involve heavy computations or blocking tasks. To avoid delays, optimize queries, use async processing, and offload long-running tasks to background workers.

Use asynchronous API calls (async/await, Axios) to prevent UI blocking.

Implement caching (React Query, SWR) to reduce redundant requests.

Batch requests, when possible, to minimize network overhead.

Optimize request triggers (debouncing, throttling) for user input-driven queries.

Show loading indicators to improve user experience while fetching data.
Laxman Reddy Revuri 5,400 Reputation points Microsoft External Staff Moderator

2025-04-07T17:26:55.8866667+00:00

Hi @Priya Rai
We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.
Laxman Reddy Revuri 5,400 Reputation points Microsoft External Staff Moderator

2025-04-08T19:53:28.8233333+00:00

Hi @Priya Rai
We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.

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Best Practices for Integrating a Modular FastAPI Backend with a React Frontend

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