Using redis for caching in your node api, you will be able to return the response to your client extremely faster. Think of a response time of **500 milliseconds to just 5 milliseconds**. Incredible right? Follow these steps to build your node api with caching using redis.

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* Setup NodeJs API

```javascript
npm init -y
npm i express redis axios nodemon
```

* server.js

  ```javascript
  const express = require("express");
  const app = express();
  
  app.listen(3000, () => {
    console.log(`Server running on port 3000`);
  });
  ```
* package.json

  ```javascript
   "scripts": {
      "start": "nodemon server.js"
    },
  ```
* Now in server.js, make a request to api to load posts. This could be your database query.

  ```javascript
  const axios = require("axios");
  
  app.get("/posts", async (req, res) => {
    try {
      const { data } = await axios.get(
        `https://jsonplaceholder.typicode.com/posts`
      );
      return res.json(data);
    } catch (error) {
      console.log(error);
    }
  });
  ```

Now open postman or browser and make a request to *http://localhost:3000/api/posts.* You will notice that it took almost 500ms to get the response.

 ![API request to Node API. Response time is 434ms.](https://tutorial-image-bucket.s3.amazonaws.com/7VtRnZfrHe7sxxE38qtQb.jpeg)

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* To improve response time, we will use redis. Let’s first install it using brew (for mac). Visit [redis website](https://redis.io/) for other installation guide.

  ```javascript
  brew install redis
  brew services start redis
  ```
* Test if redis server is running

  ```javascript
  redis-cli ping
  ```
* Back to server.js. Make a redis connection:

  ```javascript
  const redis = require("redis");
  
  // connect to redis
  const client = redis.createClient({
    url: "redis://localhost:6379",
  });
  client.connect();
  ```
* Now on the api request, send the cached data if exist otherwise cache. Use redis client `set` and `get` functions to save and retrieve data.

  ```javascript
  app.get("/api/posts", async (req, res) => {
    let cached = await client.get("posts");
    if (cached) {
      res.json(JSON.parse(cached));
    } else {
      console.log("Fetching data from API");
      const { data } = await axios.get(
        "https://jsonplaceholder.typicode.com/posts"
      );
      await client.set("posts", JSON.stringify(data));
      res.json(data);
    }
  });
  ```
* Now using redis, the response time has been reduced from 500ms to just 5ms.

   ![API request to Node API with Redis. Response time is 5ms.](https://tutorial-image-bucket.s3.amazonaws.com/LteKXhuCTMpbZy7NWleIt.jpeg)

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NodeJs Redis Caching for faster API response

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