Written: August 14, 2026 · Updated: August 15, 2026
For JSON APIs, the standard Content-Type is application/json. That tells clients and servers to parse the body as JSON rather than plain text or form data.
In Express, set the header on responses and rely on express.json() (or equivalent) to parse incoming JSON bodies.
Response header example
res.set('Content-Type', 'application/json');
res.status(200).send(JSON.stringify({ ok: true }));
// or simply:
res.status(200).json({ ok: true });Request parsing
const express = require('express');
const app = express();
app.use(express.json()); // reads application/json bodies
app.post('/api', (req, res) => {
res.json({ youSent: req.body });
});Avoid text/json or inventing custom types unless you have a documented legacy constraint. Stick to application/json for modern APIs.
Quick checklist
- Send Content-Type: application/json; charset=utf-8 when relevant
- Pair it with Accept: application/json on clients that care
- Validate JSON shape after parsing—headers alone are not security
Keep learning
If this walkthrough on Which JSON Content-Type to Use in Node.js helped, open the code again and change one input or assumption. Small experiments beat rereading the same example.
Want more step-by-step tutorials like this? Browse blog.xqa.io — and tell us which topic you want next.
