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MMKV is an efficient, small, easy-to-use mobile key-value storage framework used in the WeChat application. It's currently available on both Android, iOS/macOS, Win32 and POSIX.

• Efficient. MMKV uses mmap to keep memory synced with file, and protobuf to encode/decode values, making the most of Android to achieve best performance.

  • Multi-Process concurrency: MMKV supports concurrent read-read and read-write access between processes.

• Easy-to-use. You can use MMKV as you go. All changes are saved immediately, no sync, no apply calls needed.

• Small.

  • A handful files: MMKV contains process locks, encode/decode helpers and mmap logics and nothing more. It's really tidy.
  • About 60K in binary size: MMKV adds about 60K per architecture on App size, and much less when zipped (apk).

Add the following lines to build.gradle on your app module:

dependencies {
    implementation 'com.tencent:mmkv-static:1.2.6'
    // replace "1.2.6" with any available version
}

For other installation options, see Android Setup.

You can use MMKV as you go. All changes are saved immediately, no sync, no apply calls needed.
Setup MMKV on App startup, say your Application class, add these code:

public void onCreate() {
    super.onCreate();

    String rootDir = MMKV.initialize(this);
    System.out.println("mmkv root: " + rootDir);
    //……
}

MMKV has a global instance, you can use it directly:

import com.tencent.mmkv.MMKV;
    
MMKV kv = MMKV.defaultMMKV();

kv.encode("bool", true);
boolean bValue = kv.decodeBool("bool");

kv.encode("int", Integer.MIN_VALUE);
int iValue = kv.decodeInt("int");

kv.encode("string", "Hello from mmkv");
String str = kv.decodeString("string");

MMKV also supports Multi-Process Access. Full tutorials is here Android Tutorial.

Writing random int for 1000 times, we get this chart: For more benchmark data, please refer to our benchmark.

• Efficient. MMKV uses mmap to keep memory synced with file, and protobuf to encode/decode values, making the most of iOS to achieve best performance.

• Easy-to-use. You can use MMKV as you go, no configurations needed. All changes are saved immediately, no synchronize calls needed.

• Small

  • A handful files: MMKV contains encode/decode helpers and mmap logics and nothing more. It's really tidy.
  • Less than 30K in binary size: MMKV adds less than 30K per architecture on App size, and much less when zipped (ipa).

1. Install CocoaPods;
2. Open terminal, cd to your project directory, run pod repo update to make CocoaPods aware of the latest available MMKV versions;
3. Edit your Podfile, add pod 'MMKV' to your app target;
4. Run pod install;
5. Open the .xcworkspace file generated by CocoaPods;
6. Add #import <MMKV/MMKV.h> to your source file and we are done.

For other installation options, see iOS/macOS Setup.

You can use MMKV as you go, no configurations needed. All changes are saved immediately, no synchronize calls needed. Setup MMKV on App startup, in your -[MyApp application: didFinishLaunchingWithOptions:], add these lines:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // init MMKV in the main thread
    [MMKV initializeMMKV:nil];

    //...
    return YES;
}

MMKV has a global instance, that can be used directly:

MMKV *mmkv = [MMKV defaultMMKV];
    
[mmkv setBool:YES forKey:@"bool"];
BOOL bValue = [mmkv getBoolForKey:@"bool"];
    
[mmkv setInt32:-1024 forKey:@"int32"];
int32_t iValue = [mmkv getInt32ForKey:@"int32"];
    
[mmkv setString:@"hello, mmkv" forKey:@"string"];
NSString *str = [mmkv getStringForKey:@"string"];

MMKV also supports Multi-Process Access. Full tutorials can be found here.

Writing random int for 10000 times, we get this chart: For more benchmark data, please refer to our benchmark.

• Efficient. MMKV uses mmap to keep memory synced with file, and protobuf to encode/decode values, making the most of Win32 to achieve best performance.

  • Multi-Process concurrency: MMKV supports concurrent read-read and read-write access between processes.

• Easy-to-use. You can use MMKV as you go. All changes are saved immediately, no save, no sync calls needed.

• Small.

  • A handful of files: MMKV contains process locks, encode/decode helpers and mmap logics and nothing more. It's really tidy.
  • About 10K in binary size: MMKV adds about 10K on application size, and much less when zipped.

1. Getting source code from git repository:

   git clone https://github.com/Tencent/MMKV.git
   

2. Add Win32/MMKV/MMKV.vcxproj to your solution;

3. Add MMKV project to your project's dependencies;

4. Add $(OutDir)include to your project's C/C++ -> General -> Additional Include Directories;

5. Add $(OutDir) to your project's Linker -> General -> Additional Library Directories;

6. Add MMKV.lib to your project's Linker -> Input -> Additional Dependencies;

7. Add #include <MMKV/MMKV.h> to your source file and we are done.

note:

1. MMKV is compiled with MT/MTd runtime by default. If your project uses MD/MDd, you should change MMKV's setting to match your project's (C/C++ -> Code Generation -> Runtime Library), or wise versa.
2. MMKV is developed with Visual Studio 2017, change the Platform Toolset if you use a different version of Visual Studio.

For other installation options, see Win32 Setup.

You can use MMKV as you go. All changes are saved immediately, no sync, no save calls needed.
Setup MMKV on App startup, say in your main(), add these lines:

#include <MMKV/MMKV.h>

int main() {
    std::wstring rootDir = getYourAppDocumentDir();
    MMKV::initializeMMKV(rootDir);
    //...
}

MMKV has a global instance, that can be used directly:

auto mmkv = MMKV::defaultMMKV();

mmkv->set(true, "bool");
std::cout << "bool = " << mmkv->getBool("bool") << std::endl;

mmkv->set(1024, "int32");
std::cout << "int32 = " << mmkv->getInt32("int32") << std::endl;

mmkv->set("Hello, MMKV for Win32", "string");
std::string result;
mmkv->getString("string", result);
std::cout << "string = " << result << std::endl;

MMKV also supports Multi-Process Access. Full tutorials can be found here Win32 Tutorial.

• Efficient. MMKV uses mmap to keep memory synced with file, and protobuf to encode/decode values, making the most of POSIX to achieve best performance.

  • Multi-Process concurrency: MMKV supports concurrent read-read and read-write access between processes.

• Easy-to-use. You can use MMKV as you go. All changes are saved immediately, no save, no sync calls needed.

• Small.

  • A handful of files: MMKV contains process locks, encode/decode helpers and mmap logics and nothing more. It's really tidy.
  • About 7K in binary size: MMKV adds about 7K on application size, and much less when zipped.

1. Getting source code from git repository:

   git clone https://github.com/Tencent/MMKV.git
   

2. Edit your CMakeLists.txt, add those lines:

   add_subdirectory(mmkv/POSIX/src mmkv)
   target_link_libraries(MyApp
       mmkv)

3. Add #include "MMKV.h" to your source file and we are done.

For other installation options, see POSIX Setup.

You can use MMKV as you go. All changes are saved immediately, no sync, no save calls needed.
Setup MMKV on App startup, say in your main(), add these lines:

#include "MMKV.h"

int main() {
    std::string rootDir = getYourAppDocumentDir();
    MMKV::initializeMMKV(rootDir);
    //...
}

MMKV has a global instance, that can be used directly:

auto mmkv = MMKV::defaultMMKV();

mmkv->set(true, "bool");
std::cout << "bool = " << mmkv->getBool("bool") << std::endl;

mmkv->set(1024, "int32");
std::cout << "int32 = " << mmkv->getInt32("int32") << std::endl;

mmkv->set("Hello, MMKV for Win32", "string");
std::string result;
mmkv->getString("string", result);
std::cout << "string = " << result << std::endl;

MMKV also supports Multi-Process Access. Full tutorials can be found here POSIX Tutorial.

Full FAQ.