Ktor Server example deployed on Render Cloud Hosting

https://render.com/

Free Tier usage

Provides just enough RAM and CPU 512MB/0.1 for JVM app

• Link GitHub account to Render
• Allow access to the GitHub repo
• Create a new Render Web Service for Docker
• Set a service name (will be accessible at https://[servicename].onrender.com/)
• Build & Deploy settings
• Set repo branch
• Set health check to /health
• Leave Dockerfile and other settings to defaults

Multistage Dockerfile

Dockerfile

• Stage 1 - Cache Gradle dependencies
• Stage 2 - Run the gradle build to create a fatJar with all dependencies
• Stage 3 - Containerize the executable jar

Alternative https://feedback.render.com/features/p/deploy-docker-images-from-public-private-registries

Deploy Application log on start-up

The JDK 25 default JVM ergonomics uses Heap at 1/64th of RAM and 1 available CPU uses SerialGC in a limited system.

 -XX:-AOTInvokeDynamicLinking -XX:-AOTRecordTraining -XX:-AOTReplayTraining -XX:InitialHeapSize=8388608 -XX:MaxHeapSize=134217728 -XX:MinHeapSize=6815736 -XX:+PrintCommandLineFlags -XX:ReservedCodeCacheSize=251658240 -XX:+SegmentedCodeCache -XX:-THPStackMitigation -XX:+UseCompressedOops -XX:+UseSerialGC 
[info][gc,init] CardTable entry size: 512
[info][gc,init] Version: 25.0.2+10-LTS (release)
[info][gc,init] CPUs: 8 total, 1 available
[info][gc,init] Memory: 512M
[info][gc,init] Large Page Support: Disabled
[info][gc,init] NUMA Support: Disabled
[info][gc,init] Compressed Oops: Enabled (32-bit)
[info][gc,init] Heap Min Capacity: 8M
[info][gc,init] Heap Initial Capacity: 8M
[info][gc,init] Heap Max Capacity: 128M
[info][gc,init] Pre-touch: Disabled
[main] INFO  io.ktor.server.Application - Autoreload is disabled because the development mode is off.
[main] INFO  i.s.c.v.i.CodegenIgnoreProcessor - No .swagger-codegen-ignore file found.
[main] INFO  i.s.codegen.v3.AbstractGenerator - writing file /docs/index.html
[main] INFO  i.s.codegen.v3.AbstractGenerator - writing file /docs/.swagger-codegen-ignore
[main] INFO  i.s.codegen.v3.AbstractGenerator - writing file /docs/.swagger-codegen/VERSION
[main] INFO  io.ktor.server.Application - Application started in 21.202 seconds.
[DefaultDispatcher-worker-1] INFO  io.ktor.server.Application - Responding at http://0.0.0.0:8080

Alternatives without Credit Card

• https://www.koyeb.com/docs/faqs/pricing#is-there-a-free-tier
  • One free web Service in the Frankfurt or Washington, D.C. regions with 512MB of RAM, 0.1 vCPU, and 2GB of SSD.
• https://mogenius.com
  • Free signups currently suspended
  • Supports DockerHub and other container registries
• https://fly.io https://fly.io/blog/free-postgres/#a-note-about-credit-cards
  • Free limited to 256MB
  • Supports container registries
• https://railway.app/ https://blog.railway.app/p/updates-on-plans