POST, Headers & Query Params
Send data and configure requests properly.
POST, Headers & Query Params is a free Kotlin Multiplatform Academy lesson on CoddyKit — lesson 3 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 Kotlin Multiplatform Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Sending Data Up
Reading is half the story. Now you will send data with POST and shape requests using headers and query params.
Call post for Writes
Use client.post when you create or update something on the server, like submitting a new user.
val response = client.post("https://api.example.com/users")Set a Request Body
Attach data with setBody inside the request block, passing the object you want the server to receive.
client.post(url) { setBody(newUser) }Tell the Server the Type
Set contentType so the server knows the body is JSON and parses it correctly.
contentType(ContentType.Application.Json)Add Headers
Use the headers block to send extra metadata, such as an authorization token, with any request.
headers { append("Authorization", "Bearer abc123") }Single Header Shortcut
For just one header, the header function is shorter and reads cleanly inside the request block.
header("X-App-Version", "1.0.0")Query Parameters
Add filters or paging with the parameter function, and Ktor appends them to the URL for you.
client.get(url) { parameter("page", 2) }Several Params at Once
Call parameter multiple times to build a full query string without manual concatenation.
parameter("sort", "name")
parameter("limit", 20)Read the POST Response
A POST returns a response just like GET, so you can deserialize the created item straight into a typed model.
val created: User = response.body()Combine It All
Real requests often mix body, headers and params together inside one tidy request block.
client.post(url) { header("Auth", t); setBody(u) }Same on Every Platform
POST, headers and params all behave identically across Android and iOS, so this request logic stays fully shared.
Quick Check
Which function attaches data to a POST request?
Recap
Use post with setBody and contentType to send data, add metadata with headers, and refine URLs with parameter. All of it stays shared.
Frequently asked questions
Is the “POST, Headers & Query Params” lesson free?
Yes — the full text of “POST, Headers & Query Params” is free to read here on the web, and the Kotlin Multiplatform 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 Kotlin Multiplatform Academy course, upgrade to CoddyKit PRO.
What will I learn in “POST, Headers & Query Params”?
Send data and configure requests properly. You practise Kotlin Multiplatform 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 Kotlin Multiplatform Academy?
No prior experience is required. Kotlin Multiplatform Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 3 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “POST, Headers & Query Params” 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 Kotlin Multiplatform Academy lesson?
Yes. Every Kotlin Multiplatform 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
- Add Ktor & Pick Platform Engines
- Your First GET Request
- POST, Headers & Query Params
- Timeouts, Logging & Base URLs