Setup

1) Prerequisites

Java 17 or later
Spring Boot 4.x application
Maven or your application's Maven Wrapper

2) Add the starter dependency

<dependency>
  <groupId>com.julien-dubois.bootui</groupId>
  <artifactId>bootui-spring-boot-starter</artifactId>
  <version>1.0.0</version>
</dependency>

3) Run your app in development mode

./mvnw spring-boot:run -Dspring-boot.run.profiles=dev

BootUI also activates automatically when spring-boot-devtools is on the classpath. To force it on or off:

bootui.enabled=AUTO
bootui.enabled=ON
bootui.enabled=OFF

prod and production profiles disable BootUI unless bootui.enabled=ON is set. Invalid bootui.enabled values fail closed and keep BootUI disabled.

Safety defaults

BootUI is intended for local development only. By default it:

Activates in AUTO mode only for the dev / local profiles or DevTools.
Rejects non-loopback requests.
Permits /bootui/** through Spring Security when Spring Security is present, with a startup warning, so the local console remains directly reachable while the loopback-only filter still applies.
Masks secret-like configuration values.
Exposes the local Actuator endpoints used by BootUI panels when BootUI is active.
Captures local application spans for the Traces panel when telemetry and the panel are enabled.
Disables itself for prod / production profiles.
Stores runtime configuration overrides in .bootui/application-bootui.properties, not in your source config files.

Every visible panel can be disabled with bootui.panels.<panel-id>.enabled=false. Panels with mutating browser actions can also be made read-only with bootui.panels.<panel-id>.read-only=true, and bootui.read-only=true makes the whole BootUI application read-only. See the property reference for the full panel list.

Runtime overrides

The Configuration panel can create, update, and delete local runtime overrides. Overrides are stored in .bootui/application-bootui.properties by default, loaded at high precedence on the next startup, and never modify your application source configuration. Already-bound @ConfigurationProperties beans may keep their previous value until the app restarts; BootUI returns that warning with every override mutation.

Troubleshooting

Symptom	Check
`/bootui` returns 404	Use the `dev` or `local` profile, add DevTools, or set `bootui.enabled=ON`.
BootUI is disabled in `prod`	This is intentional; only `bootui.enabled=ON` can force activation with a disabled profile.
Browser is rejected	BootUI accepts loopback callers by default. Use `bootui.allow-non-localhost=true` only for a trusted local network.
Spring Security blocks UI	BootUI auto-registers a `/bootui/**` permit-all chain when Spring Security is active; check for a custom higher-priority chain.
A panel is empty	Enable the relevant Actuator endpoint or optional Spring module; BootUI degrades to stable empty DTOs when data is unavailable.
Startup Timeline is empty	Leave `bootui.startup.enabled=true` and `bootui.startup.capacity` greater than zero, or provide your own `BufferingApplicationStartup`.
Secrets are hidden	Default exposure is `MASKED`; use `METADATA_ONLY` to hide all values or `FULL` only in trusted local sessions.