POST Sensor Readings
Send your data to a backend endpoint.
POST Sensor Readings is a free Arduino & IoT Academy lesson on CoddyKit — lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Arduino & IoT Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Now You Send Data Out
GET pulls data in. To push your sensor readings up to a server, you use a POST request instead. 📤
GET vs POST
A GET asks for data, while a POST sends a body of data to the server to create or store something new.
Same Setup as GET
You still create an HTTPClient and call begin() with the endpoint URL. Only the sending step changes for a POST.
HTTPClient http;
http.begin("http://api.example.com/readings");Build a Payload
Decide what to send. A small JSON string holding your readings is a clean, standard way to package the data.
String body = "{\"temp\":24.5}";Tell the Server the Type
Set a Content-Type header so the server knows your body is JSON. Without it, the server may misread your data.
http.addHeader("Content-Type", "application/json");Send with POST
Call POST() and pass your body. It returns a status code just like GET did, so you can confirm it worked.
int code = http.POST(body);Confirm It Was Stored
A 200 or 201 means the server accepted your data. 201 specifically means a new record was created.
if (code == 200 || code == 201) {
// stored
}Read Any Reply
Servers often reply to a POST too, maybe an id or a confirmation. Read it with getString() if you need it.
String reply = http.getString();Close the Connection
As always, call end() after a POST to release the connection and keep your board healthy for the next send.
http.end();Send on a Schedule
You rarely POST every loop. Read a sensor, then upload once every few seconds or minutes to save power and bandwidth.
Match the Server Shape
The server expects fields in a specific format. If your JSON keys or types are wrong, it will reject the reading.
Quick Check
You are sending a JSON body to your backend. Which request method fits?
Recap
You packaged readings as JSON, set the Content-Type header, sent them with POST(), checked the code, and closed up. Your data is in the cloud. 🎉
Frequently asked questions
Is the “POST Sensor Readings” lesson free?
Yes — the full text of “POST Sensor Readings” is free to read here on the web, and the Arduino & IoT Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Arduino & IoT Academy course, upgrade to CoddyKit PRO.
What will I learn in “POST Sensor Readings”?
Send your data to a backend endpoint. You practise Arduino & IoT Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Arduino & IoT Academy?
No prior experience is required. Arduino & IoT Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 2 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “POST Sensor Readings” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Arduino & IoT Academy lesson?
Yes. Every Arduino & IoT Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- GET Data from an API
- POST Sensor Readings
- Parse JSON Responses
- Use HTTPS Securely