Integrating TypeScript with Twilio Functions and Twilio Programmable SMS allows developers to create serverless applications that are natively integrated with the Twilio ecosystem, supporting features such as SMS messages. To achieve this, a developer can scaffold a boilerplate using the Twilio Serverless Toolkit, install required dependencies, and configure TypeScript for compilation. The project configuration involves setting up a `tsconfig.json` file to specify target JavaScript version, module system, and strict mode. A functions folder is created within the source directory, and the compiled functions are deployed to the Twilio Runtime using the `--functions-folder` flag. Testing a TypeScript function involves creating a test file with a handler that returns a response to a client request. Integrating Twilio Programmable SMS requires accessing the pre-initialized Twilio client instance through the context object, sending an SMS message via the Twilio SMS REST API, and handling errors using a try/catch block or higher-order functions. Deploying the function involves running `npm run deploy`, which fires the predeploy hook to re-compile the project and uses the build/functions files as functions in the Twilio Runtime.