Get traces from an existing Java service without changing a line of code: one JVM flag, the standard OpenTelemetry agent, and every request queryable with SQL. From the team behind Pydantic. Free for 10 million spans, logs, and metrics a month.
curl -LO https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases/latest/download/opentelemetry-javaagent.jar
export OTEL_SERVICE_NAME=hello-java
export OTEL_EXPORTER_OTLP_ENDPOINT=https://logfire-us.pydantic.dev
export OTEL_EXPORTER_OTLP_HEADERS='Authorization=your-write-token'
export OTEL_EXPORTER_OTLP_PROTOCOL=http/protobuf
java -javaagent:opentelemetry-javaagent.jar -jar your-app.jarDownload the OpenTelemetry Java agent, set four environment variables, and add one JVM flag. Use the EU endpoint instead if your project is in the EU region. There is no Logfire Java SDK to adopt: Logfire is the OTLP endpoint the standard agent reports to. Full details are in the Java setup guide.
What lands in Logfire:
One request, top to bottom — produced by the OpenTelemetry Java agent, with no application code changes.
The OpenTelemetry Java agent instruments supported libraries at class-load time. Your servlet container, JDBC driver, HTTP client, and messaging library start producing spans because of a JVM flag, not because you edited them. For an existing Java service that nobody wants to refactor, this is the cheapest observability you can buy.
The OpenTelemetry Java agent instruments Spring Boot, Tomcat, Jetty, Netty, JDBC, Hibernate, Kafka, gRPC, Apache HttpClient, Cassandra, and much of the rest of its instrumentation catalogue. That coverage is maintained by the OpenTelemetry project rather than by a single vendor, so it keeps pace with the ecosystem rather than with one company's roadmap.
Logfire is configured entirely through OTEL_ environment variables: an endpoint, a header, a protocol. Your application never references Logfire. Repoint those variables at another OpenTelemetry backend, or at your own collector, and nothing in the app changes.
Logfire is not just tracing. Send metrics and structured logs alongside your traces, build dashboards, and set alerts, all in the same OpenTelemetry-native project, and query all of it with the same SQL.
Query your traces, metrics, and logs with PostgreSQL-compatible SQL. Any question you can express in SQL becomes a dashboard, an alert, or an ad-hoc investigation, and AI assistants are already fluent in it.
select
attributes->>'http.route' as route,
count(*) as requests,
avg(duration) as avg_seconds
from records
where duration > 1
group by route
order by avg_seconds desc;Your traces, metrics, and logs are queryable with real SQL, no proprietary query language to learn. Any question you can express becomes a dashboard, an alert, or a one-off investigation.
“You can tell that Pydantic Logfire was built by people who use it.”
No, and you do not need one. Java uses the standard OpenTelemetry auto-instrumentation agent, and Logfire is the OTLP backend it reports to. That means there is nothing proprietary to adopt and nothing to remove later. First-party Logfire SDKs exist for Python, TypeScript, and Rust.
No. The OpenTelemetry Java agent attaches at JVM start with the -javaagent flag and instruments supported libraries as they are loaded, so your servlet container, JDBC driver, HTTP client, and messaging library produce spans without any source changes. You can add manual spans later for your own business operations.
The most common cause is protocol. Logfire expects OTEL_EXPORTER_OTLP_PROTOCOL set to http/protobuf, while some OpenTelemetry setups default to gRPC. After that, check the endpoint matches your project's data region and that the Authorization header carries a valid write token.
Yes. Spring Boot is covered by the OpenTelemetry Java agent's instrumentation catalogue, so the same -javaagent flag applies with no extra configuration. The agent also covers JDBC, Kafka, and gRPC among many others.
No. Configuration is entirely standard OTEL_ environment variables, so your application has no knowledge of Logfire at all. Repoint the endpoint at a different OpenTelemetry-compatible backend at any time, or self-host, without touching your application or its instrumentation.
Get started with 10 million free spans, logs, and metrics per month. No credit card required.