Does Keploy replace Spock?

No. Keep Spock for unit tests, where it is the right tool. Keploy covers the integration layer, where the cost is the dependencies rather than the assertions.

Do I have to change my Groovy code?

No. Keploy runs the process you already run and captures at the socket, so no annotation, no wrapper and no dependency injection change is needed.

What happens when a dependency changes?

Re-record. One command refreshes every captured interaction in the suite, so a changed contract shows up as a diff rather than as a silently passing stale mock.

Does Keploy replace Spock's data tables?

No, and it should not. Data tables are excellent for exercising pure logic over many inputs. Keploy covers the integration path, where the cost is the dependency rather than the input matrix.

Can I run this in CI?

Yes, and that is the point: replay needs nothing running. No database service, no broker, no network access to upstreams, so the job is the same on every runner.

Keploy as a Groovy testing framework

Keploy tests Groovy services by recording real HTTP and database traffic from a running process, then replaying it as assertions. There is no Spock interaction to declare and nothing to mock by hand, because capture happens below the JVM at the socket.

Generate Groovy tests free

keploy record -c "java -jar build/libs/app.jar"

18.4K+

1.2M+300M+mocks createdSlack

What Keploy gives a Groovy team

Any Groovy service, unchanged

Keploy runs the assembled JAR. Grails, Spring Boot with Groovy, Ratpack and Micronaut all record identically.

Groovy 3 and 4
Grails, Spring Boot, Ratpack
Gradle or Maven
No plugin needed

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The problem

Why Groovy integration tests slow teams down

The friction is rarely the assertions. It is everything around them — spinning up dependencies, keeping mocks honest, and repairing tests after every refactor.

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Three ways to do it

Testing Groovy: by hand, with Spock, or with Keploy

Spock describes the exchange by hand and still needs the dependency supplied. Keploy records both halves once and replays them with nothing running.

By hand

Spock

With Keploy

Select any row for the full comparison, with code.

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Same coverage, three costs

What you write for Groovy vs what Keploy records

All three produce the same assertion. Only the third still passes after the next refactor without anyone editing it.

By hand2–4 hours

OrderControllerSpec.groovy

hand-written

import spock.lang.Specification

class OrderControllerSpec extends Specification {

def repository = Mock(OrderRepository)

def payments = Mock(PaymentClient)

def controller = new OrderController(repository, payments)

def "confirms an order"() {

given:

// Interaction described here, then asserted against that description.

repository.findById("o-1") >> new Order("o-1", 4200, "NEW")

payments.authorize(_) >> new Auth("AUTHORIZED")

when:

def res = controller.confirm("o-1")

then:

res.status == "CONFIRMED"

}

A Spock mock returns objects, so the JDBC driver never runs.

Spock1–2 hours

OrderControllerWireMockSpec.groovy

tool-assisted

import spock.lang.Specification

import static com.github.tomakehurst.wiremock.client.WireMock.*

class OrderControllerWireMockSpec extends Specification {

@Shared wireMock = new WireMockServer(8787)

def setupSpec() {

wireMock.start()

// One stub mapping per outbound URL, written by hand.

stubFor(post(urlEqualTo("/v1/payment_intents/tok_123/confirm"))

.willReturn(okJson('{"status":"AUTHORIZED"}')))

}

// A real Postgres is still needed, migrated and seeded per run.

def "confirms an order"() {

expect:

controller.confirm("o-1").status == "CONFIRMED"

}

WireMock serves the upstream. The database is still a real one.

With Keploy~5 minutes

keploy/test-set-0/test-1.yaml

auto-generated

version: api.keploy.io/v1beta1

kind: Http

name: test-1

spec:

req:

method: POST

url: /orders/o-1/confirm

resp:

status_code: 200

body: '{"id":"o-1","status":"CONFIRMED","total":4200}'

assertions:

noise:

- body.confirmedAt

---

kind: Postgres

spec:

query: select id, total, status from orders where id = $1

rows:

- { id: "o-1", total: 4200, status: "NEW" }

---

kind: Http

spec:

request:

url: https://api.payments.example.com/v1/payment_intents/tok_123/confirm

response:

body: '{"status":"AUTHORIZED"}'

Recorded from one real request. Nothing here was typed by hand.

Times are estimates for authoring one endpoint’s coverage from scratch, not measurements.

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Keploy vs the alternatives

Groovy testing tools, compared

The options a team on the JVM actually reaches for, and where each one genuinely wins. Select a row for the full comparison.

Keploy

JUnit + Mockito

WireMock

REST Assured

Testcontainers

Postman

SmartBear ReadyAPI

Best in classStrongPartialNot covered

Assessments reflect each tool’s documented behaviour, not benchmark measurements.

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How it works

Record your Groovy app once, replay it forever

Keploy sits below your Groovy process at the network layer. It watches the calls your app already makes, then serves them back on replay so tests run with no dependencies attached.

Your Groovy appGET/api/v1/orders/{id}200

RecordingKeploy proxyeBPF · userspace

PostgreSQLPostgres protocol beneath JDBC and GORM

MySQLMySQL protocol beneath the JDBC driver

MongoDBWire protocol beneath the Mongo driver

RedisRESP beneath Lettuce and Jedis

+2 more Groovy dependencies

An example shape of a captured call. Your own endpoints and dependencies come from your real traffic, so nothing here has to be written by hand.

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Mock coverage

What Keploy mocks for Groovy, with zero config

6 of the 6 dependencies a typical Groovy service talks to are stubbed from the recording itself — no mock classes, no fixture files, no containers in CI.

Auto-mocked
PostgreSQLView page
Postgres protocol beneath JDBC and GORM
Auto-mocked
MySQLView page
MySQL protocol beneath the JDBC driver
Auto-mocked
MongoDBView page
Wire protocol beneath the Mongo driver
Auto-mocked
RedisView page
RESP beneath Lettuce and Jedis
Outbound HTTP
Auto-mocked
Outbound HTTP
Every HttpBuilder and RestTemplate call
Auto-mocked
Apache KafkaView page
Kafka protocol beneath the Java client

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Quick start

Your first Groovy test suite in under five minutes

Every command below runs against your existing Groovy service. Nothing in your source tree changes.

1
1Install the Keploy CLI
A single binary. It needs a Linux kernel with eBPF support, or Docker on macOS and Windows — and it adds nothing to your project's dependencies.
curl -sSL https://keploy.io/install.sh | bash
2
2Record your service
Pass the command you already use to start the app. Keploy runs it and watches every socket it opens.
keploy record -c "java -jar build/libs/app.jar"
3
3Exercise the paths you care about
Use curl, your frontend, or an existing smoke script. Every request becomes a test case with its Groovy calls captured alongside it.
curl -X POST localhost:8080/orders/o-1/confirm
curl localhost:8080/orders/o-1
4
4Replay in CI
Replay serves the recorded dependency responses, so the job needs no service containers and no Docker daemon.
keploy test -c "java -jar build/libs/app.jar" --delay 20