Working with YAML

How to:

Working with YAML directly on Arduino is not as straightforward as on higher-level programming environments due to memory constraints and the absence of native YAML processing libraries. However, for projects that require YAML parsing or generation, a typical approach involves using a companion computer (like a Raspberry Pi) or converting YAML files to a more Arduino-friendly format (like JSON) using external scripts. For demonstration purposes, let’s focus on the latter approach using a popular library: ArduinoJson.

Step 1: Convert your YAML configuration to JSON. You can use online tools or command-line utilities like yq.

YAML file (config.yaml):

  ssid: "YourSSID"
  password: "YourPassword"

Converted to JSON (config.json):

  "wifi": {
    "ssid": "YourSSID",
    "password": "YourPassword"

Step 2: Use the ArduinoJson library to parse the JSON file in your Arduino sketch. First, you need to install the ArduinoJson library via the Library Manager in the Arduino IDE.

Step 3: Load and parse the JSON in your code. Due to Arduino’s storage limitations, imagine the JSON string is stored in a variable or read from an SD card.

Sample Arduino sketch:

#include <ArduinoJson.h>

const char* jsonConfig = "{\"wifi\":{\"ssid\":\"YourSSID\",\"password\":\"YourPassword\"}}";

void setup() {

  StaticJsonDocument<200> doc;
  DeserializationError error = deserializeJson(doc, jsonConfig);

  if (error) {
    Serial.print(F("deserializeJson() failed: "));

  const char* ssid = doc["wifi"]["ssid"]; // "YourSSID"
  const char* password = doc["wifi"]["password"]; // "YourPassword"

  Serial.print("SSID: ");
  Serial.print("Password: ");

void loop() {
  // Nothing here for this example

Output upon running the sketch:

Password: YourPassword

This approach, involving conversion to JSON and leveraging the ArduinoJson library, allows for manageable YAML configuration handling within Arduino projects, circumventing direct YAML parsing on the microcontroller.