diff --git a/backend/audit-writer-service/src/test/java/lt/satsyuk/distributed/audit/auditwriter/blockchain/AuditLedgerContractGanacheTest.java b/backend/audit-writer-service/src/test/java/lt/satsyuk/distributed/audit/auditwriter/blockchain/AuditLedgerContractGanacheTest.java
index dc5c9bc7..7790560a 100644
--- a/backend/audit-writer-service/src/test/java/lt/satsyuk/distributed/audit/auditwriter/blockchain/AuditLedgerContractGanacheTest.java
+++ b/backend/audit-writer-service/src/test/java/lt/satsyuk/distributed/audit/auditwriter/blockchain/AuditLedgerContractGanacheTest.java
@@ -56,6 +56,7 @@
  */
 @Testcontainers(disabledWithoutDocker = true)
 class AuditLedgerContractGanacheTest {
+    private static final Instant FIXED_EVENT_TIME = Instant.parse("2026-05-15T10:15:30Z");
 
     /**
      * Deterministic account 0 private key for Ganache mnemonic
@@ -111,7 +112,7 @@ static void shutdown() {
     @Test
     void appendAuditRecord_anchorsHashAndIsHashExistsConfirmsIt() {
         byte[] hash          = randomHash();
-        BigInteger timestamp = BigInteger.valueOf(Instant.now().getEpochSecond());
+        BigInteger timestamp = BigInteger.valueOf(FIXED_EVENT_TIME.getEpochSecond());
 
         assertThat(contract.isHashExists(hash))
                 .as("hash must not exist before anchoring")
diff --git a/backend/audit-writer-service/src/test/java/lt/satsyuk/distributed/audit/auditwriter/service/BlockchainWriterServiceTest.java b/backend/audit-writer-service/src/test/java/lt/satsyuk/distributed/audit/auditwriter/service/BlockchainWriterServiceTest.java
index a676b3d3..57e24787 100644
--- a/backend/audit-writer-service/src/test/java/lt/satsyuk/distributed/audit/auditwriter/service/BlockchainWriterServiceTest.java
+++ b/backend/audit-writer-service/src/test/java/lt/satsyuk/distributed/audit/auditwriter/service/BlockchainWriterServiceTest.java
@@ -45,6 +45,7 @@
  */
 @ExtendWith(MockitoExtension.class)
 class BlockchainWriterServiceTest {
+    private static final Instant FIXED_NOW = Instant.parse("2026-05-15T10:15:30Z");
 
     @Mock private Web3j web3j;
     @Mock private Credentials credentials;
@@ -300,7 +301,7 @@ void anchorEvent_failsFastOnMissingEventId() {
         // eventId is null; occurredAt and eventType are valid → should fail on eventId check
         UserLoggedInEvent event = UserLoggedInEvent.builder().build();
         event.setEventType(EventType.USER_LOGGED_IN);
-        event.setOccurredAt(Instant.now());
+        event.setOccurredAt(FIXED_NOW);
 
         assertThatThrownBy(() -> service.anchorEvent(event))
                 .isInstanceOf(BlockchainWriterService.NonRecoverableEventException.class)
@@ -312,7 +313,7 @@ void anchorEvent_failsFastOnMissingEventType() {
         // eventId and occurredAt are valid; eventType is null → should fail on eventType check
         UserLoggedInEvent event = UserLoggedInEvent.builder().build();
         event.setEventId("00000000-0000-0000-0000-000000000001");
-        event.setOccurredAt(Instant.now());
+        event.setOccurredAt(FIXED_NOW);
         // eventType intentionally left null
 
         assertThatThrownBy(() -> service.anchorEvent(event))
@@ -370,7 +371,7 @@ void anchorEvent_allowsNullUserIdToStayAlignedWithEventStoreFallbacks() {
     void anchorEvent_allowsFutureTimestampBeyondDefaultToleranceToStayAlignedWithEventStore() {
         // Even when beyond tolerance, audit-writer should not DLT the record only due to clock skew.
         UserLoggedInEvent event = UserLoggedInEvent.of("u1", null, null);
-        event.setOccurredAt(Instant.now().plusSeconds(360));
+        event.setOccurredAt(FIXED_NOW.plusSeconds(360));
 
         TransactionReceipt receipt = new TransactionReceipt();
         receipt.setStatus("0x1");
@@ -425,7 +426,7 @@ void anchorEvent_rejectsEventIdWithWrongLength() {
     void anchorEvent_acceptsFutureTimestampWithinDefaultTolerance() {
         // Default tolerance is 300 seconds; use 299 seconds in future
         UserLoggedInEvent event = UserLoggedInEvent.of("u1", null, null);
-        event.setOccurredAt(Instant.now().plusSeconds(299));
+        event.setOccurredAt(FIXED_NOW.plusSeconds(299));
 
         TransactionReceipt receipt = new TransactionReceipt();
         receipt.setStatus("0x1");
@@ -448,7 +449,7 @@ void anchorEvent_acceptsFutureTimestampWithinDefaultTolerance() {
     void anchorEvent_allowsFutureTimestampBeyondCustomToleranceToStayAlignedWithEventStore() {
         props.setFutureTimestampToleranceSeconds(60);
         UserLoggedInEvent event = UserLoggedInEvent.of("u1", null, null);
-        event.setOccurredAt(Instant.now().plusSeconds(120));
+        event.setOccurredAt(FIXED_NOW.plusSeconds(120));
 
         TransactionReceipt receipt = new TransactionReceipt();
         receipt.setStatus("0x1");
diff --git a/backend/command-service/src/main/java/lt/satsyuk/distributed/audit/command/config/KafkaProducerConfig.java b/backend/command-service/src/main/java/lt/satsyuk/distributed/audit/command/config/KafkaProducerConfig.java
index f909bdac..d5a9ae3f 100644
--- a/backend/command-service/src/main/java/lt/satsyuk/distributed/audit/command/config/KafkaProducerConfig.java
+++ b/backend/command-service/src/main/java/lt/satsyuk/distributed/audit/command/config/KafkaProducerConfig.java
@@ -1,10 +1,10 @@
 package lt.satsyuk.distributed.audit.command.config;
 
 import lt.satsyuk.distributed.audit.event.AuditEvent;
-import org.springframework.boot.context.properties.bind.Bindable;
-import org.springframework.boot.context.properties.bind.Binder;
 import org.apache.kafka.clients.producer.ProducerConfig;
 import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.EnumerablePropertySource;
+import org.springframework.core.env.PropertySource;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -13,7 +13,7 @@
 import org.springframework.kafka.core.KafkaTemplate;
 import org.springframework.kafka.core.ProducerFactory;
 import org.apache.kafka.common.serialization.StringSerializer;
-import org.springframework.kafka.support.serializer.JsonSerializer;
+import org.springframework.kafka.support.serializer.JacksonJsonSerializer;
 
 import java.util.Map;
 import java.util.HashMap;
@@ -39,7 +39,7 @@ public ProducerFactory<String, AuditEvent> auditEventProducerFactory(
         mergeKafkaOverrides(props, environment);
         props.putIfAbsent(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
         props.putIfAbsent(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
-        props.putIfAbsent(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, JsonSerializer.class);
+        props.putIfAbsent(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, JacksonJsonSerializer.class);
         props.putIfAbsent(JSON_ADD_TYPE_HEADERS_CONFIG, false);
         return new DefaultKafkaProducerFactory<>(props);
     }
@@ -54,19 +54,34 @@ public KafkaTemplate<String, AuditEvent> auditEventKafkaTemplate(
 
     private static void mergeKafkaOverrides(Map<String, Object> props,
                                             ConfigurableEnvironment environment) {
-        Binder binder = Binder.get(environment);
+        for (PropertySource<?> propertySource : environment.getPropertySources()) {
+            if (propertySource instanceof EnumerablePropertySource<?> enumerablePropertySource) {
+                mergeKafkaOverridesFromPropertySource(props, enumerablePropertySource, environment);
+            }
+        }
+    }
 
-        binder.bind("spring.kafka.properties", Bindable.mapOf(String.class, String.class))
-                .ifBound(props::putAll);
+    private static void mergeKafkaOverridesFromPropertySource(Map<String, Object> props,
+                                                              EnumerablePropertySource<?> propertySource,
+                                                              ConfigurableEnvironment environment) {
+        for (String propertyName : propertySource.getPropertyNames()) {
+            if (propertyName.startsWith("spring.kafka.properties.")) {
+                String kafkaKey = propertyName.substring("spring.kafka.properties.".length());
+                putIfPresent(props, kafkaKey, environment.getProperty(propertyName));
+            } else if (propertyName.startsWith("spring.kafka.producer.")) {
+                String producerKey = propertyName.substring("spring.kafka.producer.".length());
+                String kafkaKey = producerKey.startsWith("properties.")
+                        ? producerKey.substring("properties.".length())
+                        : producerKey.replace('-', '.');
+                putIfPresent(props, kafkaKey, environment.getProperty(propertyName));
+            }
+        }
+    }
 
-        binder.bind("spring.kafka.producer", Bindable.mapOf(String.class, String.class))
-                .ifBound(m -> m.forEach((key, value) -> {
-                    if (key.startsWith("properties.")) {
-                        props.put(key.substring("properties.".length()), value);
-                    } else {
-                        props.put(key.replace('-', '.'), value);
-                    }
-                }));
+    private static void putIfPresent(Map<String, Object> props, String key, String value) {
+        if (value != null) {
+            props.put(key, value);
+        }
     }
 }
 
diff --git a/backend/command-service/src/test/java/lt/satsyuk/distributed/audit/command/config/KafkaProducerConfigIntegrationTest.java b/backend/command-service/src/test/java/lt/satsyuk/distributed/audit/command/config/KafkaProducerConfigIntegrationTest.java
index 53aad286..860eca63 100644
--- a/backend/command-service/src/test/java/lt/satsyuk/distributed/audit/command/config/KafkaProducerConfigIntegrationTest.java
+++ b/backend/command-service/src/test/java/lt/satsyuk/distributed/audit/command/config/KafkaProducerConfigIntegrationTest.java
@@ -32,7 +32,7 @@
 class KafkaProducerConfigIntegrationTest {
 
     private static final String JSON_SERIALIZER_FQCN =
-            "org.springframework.kafka.support.serializer.JsonSerializer";
+            "org.springframework.kafka.support.serializer.JacksonJsonSerializer";
 
     private final KafkaTemplate<String, AuditEvent> auditEventKafkaTemplate;
     private final ProducerFactory<String, AuditEvent> auditEventProducerFactory;
diff --git a/backend/common/shared-contracts/src/test/java/lt/satsyuk/distributed/audit/contracts/auth/security/JwtSecurityComponentsTest.java b/backend/common/shared-contracts/src/test/java/lt/satsyuk/distributed/audit/contracts/auth/security/JwtSecurityComponentsTest.java
index bec3a429..d56700ce 100644
--- a/backend/common/shared-contracts/src/test/java/lt/satsyuk/distributed/audit/contracts/auth/security/JwtSecurityComponentsTest.java
+++ b/backend/common/shared-contracts/src/test/java/lt/satsyuk/distributed/audit/contracts/auth/security/JwtSecurityComponentsTest.java
@@ -18,6 +18,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 class JwtSecurityComponentsTest {
+    private static final Instant FIXED_ISSUED_AT = Instant.parse("2099-05-15T10:15:30Z");
 
     @Test
     void bearerTokenConverterExtractsTokenFromAuthorizationHeader() {
@@ -52,7 +53,7 @@ void bearerTokenConverterAcceptsLowercaseBearerScheme() {
     @Test
     void jwtAuthenticationManagerMapsRolesToGrantedAuthorities() {
         JwtService jwtService = new JwtService("shared-security-test-secret-123456", "dal-test", Duration.ofMinutes(30));
-        String token = jwtService.generateToken("auditor", Set.of(UserRole.AUDITOR, UserRole.ADMIN), Instant.now());
+        String token = jwtService.generateToken("auditor", Set.of(UserRole.AUDITOR, UserRole.ADMIN), FIXED_ISSUED_AT);
 
         JwtTokenReactiveAuthenticationManager authenticationManager =
                 new JwtTokenReactiveAuthenticationManager(jwtService);
diff --git a/backend/event-store-service/src/test/java/lt/satsyuk/distributed/audit/eventstore/service/EventPersistenceServiceTest.java b/backend/event-store-service/src/test/java/lt/satsyuk/distributed/audit/eventstore/service/EventPersistenceServiceTest.java
index e941be73..9b7191d3 100644
--- a/backend/event-store-service/src/test/java/lt/satsyuk/distributed/audit/eventstore/service/EventPersistenceServiceTest.java
+++ b/backend/event-store-service/src/test/java/lt/satsyuk/distributed/audit/eventstore/service/EventPersistenceServiceTest.java
@@ -19,6 +19,7 @@
 
 import java.time.Instant;
 import java.time.LocalDateTime;
+import java.time.Month;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
@@ -72,7 +73,7 @@ void persistMapsUserLoginEventToEntityAndStoresHash() {
         assertEquals(64, saved.getEventHash().length());
         assertEquals("661fa908d63fb896bf2f5b8aca9b0db207a73e99d04af2216005bdb98237607b", saved.getEventHash());
         assertNotNull(saved.getCreatedAt());
-        assertEquals(LocalDateTime.of(2026, 5, 15, 10, 15, 30), saved.getCreatedAt());
+        assertEquals(LocalDateTime.of(2026, Month.MAY, 15, 10, 15, 30), saved.getCreatedAt());
 
         ArgumentCaptor<StoredAuditEvent> captor = ArgumentCaptor.forClass(StoredAuditEvent.class);
         verify(repository).save(captor.capture());
diff --git a/backend/query-service/src/test/java/lt/satsyuk/distributed/audit/query/integration/IntegrityCheckIntegrationTest.java b/backend/query-service/src/test/java/lt/satsyuk/distributed/audit/query/integration/IntegrityCheckIntegrationTest.java
index 1fc8518b..530c887c 100644
--- a/backend/query-service/src/test/java/lt/satsyuk/distributed/audit/query/integration/IntegrityCheckIntegrationTest.java
+++ b/backend/query-service/src/test/java/lt/satsyuk/distributed/audit/query/integration/IntegrityCheckIntegrationTest.java
@@ -44,6 +44,7 @@ class IntegrityCheckIntegrationTest {
 
     /** Valid 64-char hex hash used across multiple test cases. */
     private static final String HASH_64 = "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef";
+    private static final Instant FIXED_ISSUED_AT = Instant.parse("2099-05-15T10:15:30Z");
     private final JwtService jwtService;
 
     @SuppressWarnings("resource")
@@ -321,7 +322,7 @@ private String bearerToken(UserRole... roles) {
         return "Bearer " + jwtService.generateToken(
                 "integration-user",
                 Set.of(roles),
-                Instant.now()
+                FIXED_ISSUED_AT
         );
     }
 }
diff --git a/backend/query-service/src/test/java/lt/satsyuk/distributed/audit/query/mapper/AuditEventDtoMapperTest.java b/backend/query-service/src/test/java/lt/satsyuk/distributed/audit/query/mapper/AuditEventDtoMapperTest.java
index 1404cad1..a0d276a8 100644
--- a/backend/query-service/src/test/java/lt/satsyuk/distributed/audit/query/mapper/AuditEventDtoMapperTest.java
+++ b/backend/query-service/src/test/java/lt/satsyuk/distributed/audit/query/mapper/AuditEventDtoMapperTest.java
@@ -7,6 +7,7 @@
 import org.mapstruct.factory.Mappers;
 
 import java.time.LocalDateTime;
+import java.time.Month;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
@@ -23,7 +24,7 @@ void toDtoMapsCoreFields() {
         eventRecord.setUserId("user-15");
         eventRecord.setPayload("{\"userId\":\"user-15\"}");
         eventRecord.setEventHash("abc123xyz");
-        eventRecord.setCreatedAt(LocalDateTime.of(2026, 5, 15, 10, 30, 0));
+        eventRecord.setCreatedAt(LocalDateTime.of(2026, Month.MAY, 15, 10, 30, 0));
 
         AuditEventDto dto = mapper.toDto(eventRecord);
 
diff --git a/backend/query-service/src/test/java/lt/satsyuk/distributed/audit/query/service/AuditLogQueryServiceTest.java b/backend/query-service/src/test/java/lt/satsyuk/distributed/audit/query/service/AuditLogQueryServiceTest.java
index d1ec9855..51b34630 100644
--- a/backend/query-service/src/test/java/lt/satsyuk/distributed/audit/query/service/AuditLogQueryServiceTest.java
+++ b/backend/query-service/src/test/java/lt/satsyuk/distributed/audit/query/service/AuditLogQueryServiceTest.java
@@ -16,6 +16,7 @@
 
 import java.time.Instant;
 import java.time.LocalDateTime;
+import java.time.Month;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
@@ -126,7 +127,7 @@ private AuditEventRecord sampleRecord() {
         eventRecord.setEventId("event-101");
         eventRecord.setEventType("USER_LOGGED_IN");
         eventRecord.setUserId("user-1");
-        eventRecord.setCreatedAt(LocalDateTime.of(2026, 5, 16, 10, 0));
+        eventRecord.setCreatedAt(LocalDateTime.of(2026, Month.MAY, 16, 10, 0));
         eventRecord.setPayload("{\"userId\":\"user-1\"}");
         return eventRecord;
     }
diff --git a/frontend/audit-ui/src/app/features/audit-dashboard/audit-dashboard.component.html b/frontend/audit-ui/src/app/features/audit-dashboard/audit-dashboard.component.html
index bd6f66f1..00757c52 100644
--- a/frontend/audit-ui/src/app/features/audit-dashboard/audit-dashboard.component.html
+++ b/frontend/audit-ui/src/app/features/audit-dashboard/audit-dashboard.component.html
@@ -98,8 +98,10 @@ <h3>Payload</h3>
             <mat-label>Payload search</mat-label>
             <input
               matInput
+              id="audit-payload-search"
               [formControl]="searchControl"
               placeholder="Search event payload text"
+              aria-label="Payload search"
               (keyup.enter)="applyFilters()"
             />
             <mat-icon matSuffix aria-hidden="true">search</mat-icon>
@@ -107,19 +109,33 @@ <h3>Payload</h3>
 
           <mat-form-field appearance="outline">
             <mat-label>Event type</mat-label>
-            <input matInput [formControl]="eventTypeControl" placeholder="USER_LOGGED_IN" (keyup.enter)="applyFilters()" />
+            <input
+              matInput
+              id="audit-event-type"
+              [formControl]="eventTypeControl"
+              placeholder="USER_LOGGED_IN"
+              aria-label="Event type"
+              (keyup.enter)="applyFilters()"
+            />
           </mat-form-field>
 
           <mat-form-field appearance="outline">
             <mat-label>User ID</mat-label>
-            <input matInput [formControl]="userIdControl" placeholder="user1" (keyup.enter)="applyFilters()" />
+            <input
+              matInput
+              id="audit-user-id"
+              [formControl]="userIdControl"
+              placeholder="user1"
+              aria-label="User ID"
+              (keyup.enter)="applyFilters()"
+            />
           </mat-form-field>
 
           <mat-form-field appearance="outline" class="filter-field filter-field--wide">
             <mat-label>Date range</mat-label>
             <mat-date-range-input [formGroup]="dateRangeForm" [rangePicker]="rangePicker">
-              <input matStartDate formControlName="from" placeholder="From date" />
-              <input matEndDate formControlName="to" placeholder="To date" />
+              <input matStartDate id="audit-from-date" formControlName="from" placeholder="From date" aria-label="From date" />
+              <input matEndDate id="audit-to-date" formControlName="to" placeholder="To date" aria-label="To date" />
             </mat-date-range-input>
             <mat-datepicker-toggle matIconSuffix [for]="rangePicker"></mat-datepicker-toggle>
             <mat-date-range-picker #rangePicker></mat-date-range-picker>
diff --git a/frontend/audit-ui/src/app/features/auth-login/auth-login.component.html b/frontend/audit-ui/src/app/features/auth-login/auth-login.component.html
index 88acff38..5d804058 100644
--- a/frontend/audit-ui/src/app/features/auth-login/auth-login.component.html
+++ b/frontend/audit-ui/src/app/features/auth-login/auth-login.component.html
@@ -5,12 +5,12 @@ <h2>Sign In</h2>
     <form [formGroup]="form" (ngSubmit)="submit()" class="login-form" autocomplete="on">
       <mat-form-field appearance="outline">
         <mat-label>Username</mat-label>
-        <input matInput id="username" name="username" type="text" formControlName="username" autocomplete="username" />
+        <input matInput id="username" name="username" type="text" formControlName="username" autocomplete="username" aria-label="Username" />
       </mat-form-field>
 
       <mat-form-field appearance="outline">
         <mat-label>Password</mat-label>
-        <input matInput id="password" name="password" type="password" formControlName="password" autocomplete="current-password" />
+        <input matInput id="password" name="password" type="password" formControlName="password" autocomplete="current-password" aria-label="Password" />
       </mat-form-field>
 
       @if (errorMessage()) {