[Home](./index.md) > [@contract-case/case-definition-dsl](./case-definition-dsl.md) > [matchers](./case-definition-dsl.matchers.md) > [base](./case-definition-dsl.matchers.base.md) > [AnyMatcher](./case-definition-dsl.matchers.base.anymatcher.md) > [toJSON](./case-definition-dsl.matchers.base.anymatcher.tojson.md) ## matchers.base.AnyMatcher.toJSON() method Only override this method if you are writing a matcher in a language other than TypeScript. It exists because the ContractCase matcher format is not legal in all languages that ContractCase supports. WARNING: Do not return a string from this method. You must instead return an object that can be serialised to JSON following the matcher format described in [Extending ContractCase](https://case.contract-testing.io/docs/reference/plugin-framework). **Signature:** ```typescript toJSON(): unknown; ``` **Returns:** unknown An object in the matcher format described [in the Extending ContractCase documentation](https://case.contract-testing.io/docs/reference/plugin-framework)