Express API's

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Let’s Make Express APIs Easy (GET, POST, PUT, DELETE Explained)

If you’re learning backend development and feeling confused about APIs, trust me you’re not alone.
When I first started with Express, even simple words like routes, endpoints, methods felt scary.

But once you understand four simple methods, everything becomes clear:

👉 GET
👉 POST
👉 PUT
👉 DELETE

That’s literally all you need to build a basic backend.

So let’s break it down in the simplest, rawest way possible.

What Even Is an API?

Think of an API like a waiter in a restaurant.

You (the client) ask something →
Waiter (API) takes your request →
Kitchen (server) sends the food back.

Express just makes it easy to be that “waiter.”

1. GET — “Give me the data”
GET is the easiest.
When the frontend wants something, it uses GET.

Example:


app.get(”/users”, (req, res) => {
    let alluser = readDB()
    res.status(200).json(alluser);
});

You’re basically saying:

“Hey server, give me all the users.”

No body, no extra stuff — just fetch data.

Real use cases:

Show all products
Get user profile
Display a dashboard

2. POST — “I want to create something”
POST is used when you’re sending data to the backend.

Example:

  const { name, email } = req.body;
  if (!name || !email) {
    return res.status(400).json({ success: false, message: “name and email required” });
  }
  const id = users.length ? users[users.length - 1].id + 1 : 1;
  const newUser = { id, name, email };
  users.push(newUser);
  res.status(201).json({ success: true, data: newUser });
});Frontend sends something like:
{
  “name”: “Abdullah”,
  “email”: “abdullah@gmail.com”
}

And backend stores it.

Real use cases:

Register a user
Submit a form
Add a blog post

3. PUT — “Replace the whole thing”
PUT is for updating — but remember this:

👉 PUT replaces the entire object, not just one part.

Example:


router.put(”/users/:id”, (req, res) => {
  const id = Number(req.params.id);
  const { name, email } = req.body;
  const idx = users.findIndex(u => u.id === id);
  if (idx === -1) return res.status(404).json({ success: false, message: “User not found” });

  // replace object (PUT semantics)
  users[idx] = { id, name: name ?? users[idx].name, email: email ?? users[idx].email };
  res.json({ success: true, data: users[idx] });
});

If you update a user using PUT, you’re basically saying:

“Here is the full updated user object. Replace everything with this.”

Real use cases:

Edit full profile
Update product details
Replace blog post content

4. DELETE — “Remove this immediately”

DELETE does exactly what the name says.

Example:


router.delete(”/users/:id”, (req, res) => {
  const id = Number(req.params.id);
  const idx = users.findIndex(u => u.id === id);
  if (idx === -1) return res.status(404).json({ success: false, message: “User not found” });

  const removed = users.splice(idx, 1)[0];
  res.json({ success: true, data: removed });
});

Use it when you want to remove something: