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Free and paid Java hosting compared: the limits that decide

Most advice on Java hosting starts with price. Start with memory instead. A JVM claims heap at startup, keeps compiled code in its own memory areas and loads every class your framework needs before it answers the first request. An app that runs happily on your laptop can fail on a 512 MB instance that would carry a Node or Go service without trouble. Figures checked in November 2026.

Memory for the JVM

As a working rule, a lean app with a capped heap fits in 512 MB, and a typical Spring Boot service with a database driver is more comfortable at 1 GB. Modern JVMs read the container's memory limit, but by default they give the heap only a quarter of it: 128 MB on a 512 MB plan. Raise that share with -XX:MaxRAMPercentage, around 70 to 75 for a container that runs one app, instead of copying a fixed -Xmx from your laptop. A heap set larger than the plan allows is the usual reason for a container that restarts with exit code 137. Then compare plans by price per gigabyte, not price per instance. On that measure the spread is wide: Render's first paid instance is $7 for 512 MB, Fly.io runs 1 GB for $6.70 a month, and a Hetzner CAX11 virtual machine gives you 4 GB from EUR 6.49. The Java hosting comparison puts fifteen providers side by side on exactly these numbers.

Sleep rules on free tiers

Free Java hosting exists, but it usually sleeps. Render spins a free service down after 15 minutes without traffic, Koyeb after an hour. When the next visitor arrives, the container starts and the JVM boots from cold, which can take a minute or more. That is fine for a portfolio or a class project and annoying for anything people depend on. Northflank's Sandbox is described as always on. Oracle's Always Free VMs do not sleep on a timer, but Oracle may reclaim an instance whose CPU, network and memory use all stay under 20% for seven days. The free Java hosting breakdown lists the catches for each.

Build time and how the code arrives

Platforms build Java in two ways. Some take your repository and run Maven or Gradle for you through a buildpack: Heroku, Koyeb and Railway's Railpack all have Java support. Others expect a finished Docker image. Builds on the platform are convenient, but a Gradle build with a cold cache can take minutes, and on usage-billed platforms that time is not always free. Building the image in your own CI and pushing it keeps deploys fast and predictable. The deployment guide walks through both routes.

Tomcat hosting for WAR files

If your app is a WAR rather than a self-contained JAR, the Tomcat version decides more than the host does. Tomcat 11 implements Servlet 6.1 with the jakarta.servlet packages and needs Java 17 or newer. Apps that still import javax.servlet run only on Tomcat 9, whose 9.0.x line is supported until 31 March 2027; Apache plans a 9.1.x branch with minimal changes that receives releases until 31 December 2030.

Three providers offer Tomcat hosting with the server managed for you. AWS Elastic Beanstalk has a platform with Corretto 25 and Tomcat 11, and charges only for the EC2 instances and other resources it creates. Azure App Service on Linux lists Tomcat as a built-in stack, from about $12.41 a month on the B1 plan with 1.75 GB of RAM. Clever Cloud runs WAR files natively from about EUR 4.56 a month for 256 MiB. On any other container platform, the official Tomcat Docker image gives you the same kind of Java web hosting. The Tomcat hosting guide covers each route.

The database connection

Most Java apps also need a database, and the connection string trips up a lot of first deploys. The PostgreSQL JDBC driver expects a URL in the form jdbc:postgresql://host:port/db, while platforms often hand out a postgres://user:password@host/db URI. Heroku adds JDBC_DATABASE_URL in the JDBC format for Java apps; on other platforms you convert it yourself. Managed databases usually require encryption as well: Heroku Postgres accepts only TLS 1.2 or higher, so the URL needs sslmode=require. The database connection checklist goes through the errors one by one.

Regions and data location

If your users or your contracts are in Europe, check where the provider can run your app. Render, Koyeb and Northflank offer Frankfurt, Railway has Amsterdam, Google Cloud Run lists more than a dozen European locations, and Hetzner and Clever Cloud are European companies with data centers in Germany, Finland and France.

Payment methods

This one rules out providers faster than anything else. Railway accepts only credit cards for subscriptions. Heroku takes credit cards but no PayPal, ACH or prepaid cards. Fly.io sells prepaid credits with a $25 minimum. Without a credit card, look at Hetzner (SEPA, bank transfer, PayPal), Clever Cloud (PayPal, SEPA) or DigitalOcean (PayPal, and ACH for qualifying US customers). Oracle asks for a card even on its free tier, only to verify you.

The JDK and its license

The runtime you ship on matters as much as the host. Java 25 is the current LTS release, and Heroku already defaults new Java apps to it. Free OpenJDK builds such as Eclipse Temurin and Amazon Corretto are licensed under GPL version 2 with the Classpath Exception and can run commercial apps in production at no cost. Oracle JDK is different: version 25 is free for all users under Oracle's No-Fee Terms, but updates released after September 2028 are planned to move to the Java SE OTN license, and Oracle JDK 8, 11, 17 and 21 are free for personal and development use only. The OpenJDK vs Oracle JDK comparison explains when that matters, and the Java versions timeline shows support end dates by vendor.

Once the app is live, you will want to reach the server from anywhere. The developer tools page rates SSH and cloud console apps for phones and includes a hosting plan calculator for sizing JVM memory. Java web hosting rewards a bit of preparation, and most surprises come from the same few places: memory, sleep rules, the database URL, region and payment.