diff --git a/ps-cache-kotlin/Dockerfile b/ps-cache-kotlin/Dockerfile
new file mode 100644
index 00000000..17b63339
--- /dev/null
+++ b/ps-cache-kotlin/Dockerfile
@@ -0,0 +1,12 @@
+FROM maven:3.9-eclipse-temurin-21 AS builder
+WORKDIR /app
+COPY pom.xml .
+RUN mvn dependency:go-offline -q
+COPY src/ src/
+RUN mvn package -DskipTests -q
+
+FROM eclipse-temurin:21-jre-alpine
+WORKDIR /app
+COPY --from=builder /app/target/kotlin-app-1.0.0.jar app.jar
+EXPOSE 8080
+CMD ["java", "-jar", "app.jar"]
diff --git a/ps-cache-kotlin/README.md b/ps-cache-kotlin/README.md
new file mode 100644
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+++ b/ps-cache-kotlin/README.md
@@ -0,0 +1,122 @@
+# PS-Cache Kotlin — JDBC Prepared Statement Cache Mock Mismatch Reproduction
+
+This sample demonstrates a bug in Keploy's Postgres mock matcher where **JDBC prepared statement caching combined with connection pool eviction causes the replay to return the wrong person's data**.
+
+## The Bug
+
+The JDBC driver (PostgreSQL JDBC + HikariCP) caches prepared statements per connection. When the connection pool evicts and creates a new connection, the PS cache is cold — but the recorded mocks from the evicted connection had warm-cache structure (Bind-only, no Parse). During replay, the matcher can't distinguish between mocks from different connection windows because:
+
+1. All mocks have the same parameterized SQL: `SELECT ... WHERE member_id = ?`
+2. `bindParamMatchLen` mode only checks parameter byte-length (all int4 are 4 bytes)
+3. Sort-order prediction starts from 0 on a fresh connection, pointing to the wrong window's mocks
+
+### Real-world impact
+This was reported by a customer running a Kotlin/Spring Boot app with Agoda's travel account service. Test-6 (member_id=31) returned Alice's data (member_id=19) instead of Charlie's — **silently returning the wrong customer's financial data**.
+
+## Architecture
+
+```
+ ┌──────────────────────┐
+ HTTP requests ──> │ Kotlin + Spring Boot │
+ │ HikariCP pool=1 │
+ │ prepareThreshold=1 │
+ └──────────┬───────────┘
+ │
+ ┌──────────────────┼──────────────────┐
+ │ │ │
+ /account /evict /account
+ member=19 (pool evict) member=31
+ │ │ │
+ Connection A destroyed Connection B
+ PS cache: cold→warm PS cache: cold
+ │ │
+ 1st: Parse+Bind+Desc+Exec Parse+Bind+Desc+Exec
+ 2nd: Bind+Exec (cached PS)
+ │ │
+ mocks connID=0 mocks connID=2
+ (Alice, 1000) (Charlie, 500)
+```
+
+## How to Reproduce the Bug
+
+### Prerequisites
+```bash
+docker run -d --name pg-demo -e POSTGRES_PASSWORD=testpass -e POSTGRES_DB=demodb -p 5433:5432 postgres:16
+```
+
+### Pre-create the schema
+```bash
+docker exec pg-demo psql -U postgres -d demodb -c "
+ CREATE SCHEMA IF NOT EXISTS travelcard;
+ CREATE TABLE IF NOT EXISTS travelcard.travel_account (
+ id SERIAL PRIMARY KEY, member_id INT NOT NULL UNIQUE,
+ name TEXT NOT NULL, balance INT NOT NULL DEFAULT 0);
+ INSERT INTO travelcard.travel_account (member_id, name, balance) VALUES
+ (19, 'Alice', 1000), (23, 'Bob', 2500),
+ (31, 'Charlie', 500), (42, 'Diana', 7500);"
+```
+
+### Build the app
+```bash
+mvn package -DskipTests -q
+```
+
+### With the OLD keploy binary (demonstrates failure)
+```bash
+# Record
+sudo keploy record -c "java -jar target/kotlin-app-1.0.0.jar"
+# Hit endpoints:
+curl http://localhost:8090/account?member=19
+curl http://localhost:8090/account?member=23
+curl http://localhost:8090/evict
+curl http://localhost:8090/account?member=31
+curl http://localhost:8090/account?member=42
+# Stop recording (Ctrl+C)
+
+# Reset DB and replay
+docker exec pg-demo psql -U postgres -d demodb -c "TRUNCATE travelcard.travel_account; INSERT INTO ..."
+sudo keploy test -c "java -jar target/kotlin-app-1.0.0.jar" --skip-coverage
+```
+
+**Expected failure (without fix):**
+```
+test-5 (/account?member=31):
+ EXPECTED: {"memberId":31, "name":"Charlie", "balance":500}
+ ACTUAL: {"memberId":19, "name":"Alice", "balance":1000} ← WRONG PERSON
+```
+
+**With obfuscation enabled (worse):**
+```
+test-5: EXPECTED Charlie → ACTUAL Alice
+test-6: EXPECTED Diana → ACTUAL Bob ← TWO wrong results
+```
+
+### With the FIXED keploy binary
+```bash
+# Same steps → all tests pass, correct data for each member
+```
+
+## What the Fix Does
+
+The fix adds **recording-connection affinity** to the Postgres mock matcher (see [keploy/integrations#121](https://github.com/keploy/integrations/pull/121)):
+
+1. When the first `Bind` mock is consumed on a replay connection, its recording `connID` is stored
+2. Subsequent scoring applies +50/-50 bonus/penalty to prefer mocks from the same recording window
+3. Only activates when 2+ distinct recording connections exist (zero impact on single-connection apps)
+
+## Configuration
+
+### application.properties
+| Property | Value | Purpose |
+|----------|-------|---------|
+| `spring.datasource.hikari.maximum-pool-size` | `1` | Forces all requests through one connection |
+| `prepareThreshold=1` | JDBC URL param | Caches PS after first use |
+| `spring.sql.init.mode` | `never` | Schema created externally |
+
+### Endpoints
+
+| Endpoint | Description |
+|----------|-------------|
+| `GET /health` | Health check |
+| `GET /account?member=N` | Query travel_account by member_id (BEGIN → SELECT → COMMIT) |
+| `GET /evict` | Soft-evict HikariCP connections (forces new PG connection) |
diff --git a/ps-cache-kotlin/docker-compose.yml b/ps-cache-kotlin/docker-compose.yml
new file mode 100644
index 00000000..ca799f2e
--- /dev/null
+++ b/ps-cache-kotlin/docker-compose.yml
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+services:
+ db:
+ image: postgres:16-alpine
+ environment:
+ POSTGRES_USER: postgres
+ POSTGRES_PASSWORD: postgres
+ POSTGRES_DB: testdb
+ ports:
+ - "5433:5432"
+ volumes:
+ - pgdata:/var/lib/postgresql/data
+ - ./init.sql:/docker-entrypoint-initdb.d/init.sql
+ healthcheck:
+ test: ["CMD-SHELL", "pg_isready -U postgres"]
+ interval: 2s
+ timeout: 5s
+ retries: 5
+
+ api:
+ build: .
+ ports:
+ - "8080:8080"
+ environment:
+ DB_HOST: db
+ DB_PORT: "5432"
+ DB_USER: postgres
+ DB_PASSWORD: postgres
+ DB_NAME: testdb
+ depends_on:
+ db:
+ condition: service_healthy
+
+volumes:
+ pgdata:
diff --git a/ps-cache-kotlin/init.sql b/ps-cache-kotlin/init.sql
new file mode 100644
index 00000000..fb7bb14b
--- /dev/null
+++ b/ps-cache-kotlin/init.sql
@@ -0,0 +1,15 @@
+CREATE SCHEMA IF NOT EXISTS travelcard;
+
+CREATE TABLE IF NOT EXISTS travelcard.travel_account (
+ id SERIAL PRIMARY KEY,
+ member_id INT NOT NULL UNIQUE,
+ name TEXT NOT NULL,
+ balance INT NOT NULL DEFAULT 0
+);
+
+INSERT INTO travelcard.travel_account (member_id, name, balance) VALUES
+ (19, 'Alice', 1000),
+ (23, 'Bob', 2500),
+ (31, 'Charlie', 500),
+ (42, 'Diana', 7500)
+ON CONFLICT (member_id) DO NOTHING;
diff --git a/ps-cache-kotlin/pom.xml b/ps-cache-kotlin/pom.xml
new file mode 100644
index 00000000..287f22d5
--- /dev/null
+++ b/ps-cache-kotlin/pom.xml
@@ -0,0 +1,44 @@
+
+
+ 4.0.0
+
+ org.springframework.boot
+ spring-boot-starter-parent
+ 3.4.4
+
+ com.demo
+ kotlin-app
+ 1.0.0
+
+ 21
+ 1.9.25
+
+
+ org.springframework.bootspring-boot-starter-web
+ org.springframework.bootspring-boot-starter-jdbc
+ org.postgresqlpostgresql
+ org.jetbrains.kotlinkotlin-reflect
+ org.jetbrains.kotlinkotlin-stdlib
+
+
+ src/main/kotlin
+
+
+ org.jetbrains.kotlin
+ kotlin-maven-plugin
+ ${kotlin.version}
+
+ spring
+ ${java.version}
+
+
+ org.jetbrains.kotlinkotlin-maven-allopen${kotlin.version}
+
+ compilecompile
+
+ org.springframework.bootspring-boot-maven-plugin
+
+
+
diff --git a/ps-cache-kotlin/src/main/kotlin/com/demo/App.kt b/ps-cache-kotlin/src/main/kotlin/com/demo/App.kt
new file mode 100644
index 00000000..dceee584
--- /dev/null
+++ b/ps-cache-kotlin/src/main/kotlin/com/demo/App.kt
@@ -0,0 +1,89 @@
+package com.demo
+
+import org.springframework.boot.autoconfigure.SpringBootApplication
+import org.springframework.boot.runApplication
+import org.springframework.jdbc.core.JdbcTemplate
+import org.springframework.web.bind.annotation.GetMapping
+import org.springframework.web.bind.annotation.RequestParam
+import org.springframework.web.bind.annotation.RestController
+import org.springframework.http.ResponseEntity
+import javax.sql.DataSource
+import com.zaxxer.hikari.HikariDataSource
+
+@SpringBootApplication
+class App
+
+fun main(args: Array) {
+ runApplication(*args)
+}
+
+data class Account(
+ val id: Int,
+ val memberId: Int,
+ val name: String,
+ val balance: Int
+)
+
+@RestController
+class AccountController(private val jdbc: JdbcTemplate, private val dataSource: DataSource) {
+
+ @GetMapping("/health")
+ fun health() = mapOf("status" to "ok")
+
+ @GetMapping("/account")
+ fun getAccount(@RequestParam("member") memberId: Int): ResponseEntity {
+ val result = jdbc.execute(
+ org.springframework.jdbc.core.ConnectionCallback { conn ->
+ conn.autoCommit = false
+ try {
+ conn.prepareStatement(
+ """SELECT id, member_id, name, balance
+ FROM travelcard.travel_account
+ WHERE member_id = ?"""
+ ).use { ps ->
+ ps.setInt(1, memberId)
+ ps.executeQuery().use { rs ->
+ val account = if (rs.next()) {
+ Account(
+ id = rs.getInt("id"),
+ memberId = rs.getInt("member_id"),
+ name = rs.getString("name"),
+ balance = rs.getInt("balance")
+ )
+ } else null
+
+ conn.commit()
+ account
+ }
+ }
+ } catch (e: Exception) {
+ conn.rollback()
+ throw e
+ }
+ })
+
+ return if (result != null) {
+ ResponseEntity.ok(result)
+ } else {
+ ResponseEntity.status(404).body(mapOf("error" to "not found", "member_id" to memberId))
+ }
+ }
+
+ @GetMapping("/evict")
+ fun evict(): ResponseEntity> {
+ val hikari = dataSource as? HikariDataSource
+ ?: return ResponseEntity.status(500).body(mapOf("error" to "not a HikariDataSource"))
+
+ val mxBean = hikari.hikariPoolMXBean
+ ?: return ResponseEntity.status(500).body(mapOf("error" to "pool MXBean not available"))
+
+ mxBean.softEvictConnections()
+ Thread.sleep(500)
+
+ return ResponseEntity.ok(mapOf(
+ "evicted" to true,
+ "active" to mxBean.activeConnections,
+ "idle" to mxBean.idleConnections
+ ))
+ }
+}
diff --git a/ps-cache-kotlin/src/main/resources/application.properties b/ps-cache-kotlin/src/main/resources/application.properties
new file mode 100644
index 00000000..29fae651
--- /dev/null
+++ b/ps-cache-kotlin/src/main/resources/application.properties
@@ -0,0 +1,7 @@
+server.port=8080
+spring.datasource.url=jdbc:postgresql://${DB_HOST:localhost}:${DB_PORT:5432}/${DB_NAME:testdb}?prepareThreshold=1&preparedStatementCacheQueries=256
+spring.datasource.username=${DB_USER:postgres}
+spring.datasource.password=${DB_PASSWORD:postgres}
+spring.datasource.hikari.maximum-pool-size=1
+spring.datasource.hikari.minimum-idle=1
+spring.sql.init.mode=never
diff --git a/ps-cache-kotlin/test.sh b/ps-cache-kotlin/test.sh
new file mode 100755
index 00000000..9c4eb75a
--- /dev/null
+++ b/ps-cache-kotlin/test.sh
@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+BASE_URL="http://localhost:8080"
+
+echo "=== PS-Cache Mock Mismatch Test (Kotlin/JDBC) ==="
+
+echo "--- Window 1: Connection A ---"
+echo " /account?member=19:"
+curl -fSs "$BASE_URL/account?member=19"
+echo ""
+sleep 1
+
+echo " /account?member=23:"
+curl -fSs "$BASE_URL/account?member=23"
+echo ""
+sleep 1
+
+echo ""
+echo "--- Evict (force new connection) ---"
+echo " /evict:"
+curl -fSs "$BASE_URL/evict"
+echo ""
+sleep 1
+
+echo ""
+echo "--- Window 2: Connection B ---"
+echo " /account?member=31:"
+curl -fSs "$BASE_URL/account?member=31"
+echo ""
+sleep 1
+
+echo " /account?member=42:"
+curl -fSs "$BASE_URL/account?member=42"
+echo ""
+
+echo ""
+echo "=== Done ==="