Spring Boot or Ktor

Choose the integration that already owns application configuration and lifecycle. Do not add a second framework just to obtain image helpers.

Choose Ktor

Ktor integration is focused: it supplies thumbnail and CAPTCHA route helpers on top of the image and CAPTCHA modules. The application installs its own JSON serialization, authentication, error handling, request-size policy, and persistence. Use the Ktor image API workshop to see challenge issuance, verification, and thumbnails together.

Ktor OCR is assembled directly in the Ktor OCR workshop; the OCR library itself is framework-neutral.

Choose Spring Boot

Spring Boot integration is broader. It auto-configures local or S3 storage, optional CloudFront URL signing, health, and metrics. Choose it when Boot already owns configuration properties, bean lifecycle, Actuator, and Micrometer. Follow the Spring Boot image API workshop.

The Spring Boot OCR workshop wires the framework-neutral OCR engine into a web controller and keeps host Tesseract as an explicit runtime prerequisite.

Use the libraries directly

For batch jobs, command-line tools, or another framework, use bluetape4k-images, CAPTCHA, OCR, or Vips directly. Framework modules are adapters, not prerequisites for core processing.

Whichever path you choose, the application owns upload limits, authentication, storage credentials, response caching, and shutdown behavior.

Sources

• Ktor release module
• Spring Boot release module