TinyConfig

A lightweight configuration library for ESP8266 (Arduino/PlatformIO).
Easily store and retrieve configuration data (such as WiFi credentials, settings, etc.) in a JSON file on the ESP8266's filesystem.

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Features

• Simple API: Store and retrieve integers, floats, and strings with ease.
• JSON-based: Configuration is stored as a JSON file on LittleFS.
• Automatic file creation/reset: Handles missing or corrupt config files.
• Configurable file size: Prevents oversized config files.
• Detailed error handling: Get error codes and human-readable error messages.

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Getting Started

Hardware Requirements

• ESP8266-based board (e.g., NodeMCU, Wemos D1 Mini)
• PlatformIO or Arduino IDE

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Installation

PlatformIO

Add this library to your platformio.ini:

lib_deps =
    https://github.com/lennart080/ESP8266-TinyConfig.git
    bblanchon/ArduinoJson

Or install via the PlatformIO Library Manager.

Arduino IDE

1. Download this repository as a ZIP file.
2. In Arduino IDE, go to Sketch > Include Library > Add .ZIP Library... and select the downloaded ZIP.
3. Install the required dependencies:
   • ArduinoJson
   • LittleFS (included with ESP8266 core)

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Usage

1. Include and Create

#include <TinyConfig.h>
TinyConfig config;

2. Initialize the Filesystem

Call StartTC() in your setup() function to mount the filesystem and prepare the config file.

void setup() {
    Serial.begin(115200);

    if (!config.StartTC()) {
        Serial.println("Init failed: " + config.getLastErrorString());
        return;
    }
}

3. Set Configuration Values

Store values (such as WiFi credentials or settings):

config.set("wifi_ssid", "MyNetwork");
config.set("wifi_pass", "MyPassword");
config.set("boot_count", 1);

4. Retrieve Configuration Values

Read values from the config file, providing a fallback if the key does not exist:

String ssid = config.getString("wifi_ssid", "default_ssid");
int bootCount = config.getInt("boot_count", 0);

Serial.println("SSID: " + ssid);
Serial.print("Boot count: ");
Serial.println(bootCount);

5. Retrieve All Configuration Data

Get all configuration as a JSON string:

String allConfig = config.getAll();
Serial.println(allConfig); // Prints: {"wifi_ssid":"MySSID","wifi_pass":"MyPass",...}

Or as a DynamicJsonDocument for advanced manipulation:

DynamicJsonDocument doc = config.getAllJson();
if (doc.containsKey("wifi_ssid")) {
    Serial.println(doc["wifi_ssid"].as<String>());
}

6. Delete a Key from the Configuration

Remove a specific key and its value from the configuration:

config.deleteKey("wifi_pass");

7. Reset Configuration (Optional)

To reset the configuration file to an empty JSON object:

config.resetConfig();

8. Unmount the Filesystem

When finished, unmount the filesystem:

config.StopTC();

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API Reference

Method	Description
bool StartTC()	Mounts the filesystem and prepares the config file.
bool StopTC()	Unmounts the filesystem.
bool set(const String& key, int/float/String)	Set a value in the config.
int getInt(const String& key, int fallback)	Get an integer value or fallback.
float getFloat(const String& key, float fallback)	Get a float value or fallback.
String getString(const String& key, String fallback)	Get a string value or fallback.
String getAll(const String& fallback = "{}")	Get the entire config as a JSON string.
DynamicJsonDocument getAllJson()	Get the entire config as a DynamicJsonDocument.
bool deleteKey(const String& key)	Delete a key and its value from the config.
bool resetConfig()	Resets config to empty JSON.
void setMaxFileSize(size_t maxSize)	Set max config file size in bytes.
TinyConfigError getLastError() const	Get the last error code.
String getLastErrorString() const	Get a string describing the last error.

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Troubleshooting

• LittleFS mount failed: Ensure the filesystem is formatted and available.
• File not found: The config file will be created automatically if missing.
• File too large: Use setMaxFileSize() to increase the limit if needed.
• Not initialized: Call StartTC() before using other methods.

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License

This project is licensed under the Apache 2.0 License.

You may use, share and modify it, as long as you give credit to:

Lennart Gutjahr (2025) — Original author
gutjahrlennart@gmail.com — Email

License details: Apache License 2.0

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Credits

Based on ArduinoJson and LittleFS.