A method for providing a platform-integrated SDK capable of developing multiple platforms with single source code, includes: receiving, from a user, a build instruction in which any one of the multiple platforms is designated as a build target platform, with respect to source code integrally written for the multiple platforms; importing a software development kit (SDK), among pre-stored SDKs, corresponding to the build target platform; building the source code after the SDK is imported; and providing the built object file to the user.