diff --git a/cannamanage-api/pom.xml b/cannamanage-api/pom.xml
index 33c8016..bfa4ee4 100644
--- a/cannamanage-api/pom.xml
+++ b/cannamanage-api/pom.xml
@@ -46,11 +46,57 @@
             <artifactId>lombok</artifactId>
             <optional>true</optional>
         </dependency>
+        <!-- Spring Security -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-security</artifactId>
+        </dependency>
+        <!-- Bean Validation -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-validation</artifactId>
+        </dependency>
+        <!-- JWT (JJWT) -->
+        <dependency>
+            <groupId>io.jsonwebtoken</groupId>
+            <artifactId>jjwt-api</artifactId>
+            <version>0.12.6</version>
+        </dependency>
+        <dependency>
+            <groupId>io.jsonwebtoken</groupId>
+            <artifactId>jjwt-impl</artifactId>
+            <version>0.12.6</version>
+            <scope>runtime</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.jsonwebtoken</groupId>
+            <artifactId>jjwt-jackson</artifactId>
+            <version>0.12.6</version>
+            <scope>runtime</scope>
+        </dependency>
+        <!-- OpenAPI / Swagger UI -->
+        <dependency>
+            <groupId>org.springdoc</groupId>
+            <artifactId>springdoc-openapi-starter-webmvc-ui</artifactId>
+            <version>2.8.6</version>
+        </dependency>
+        <!-- H2 for tests -->
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <!-- Test -->
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-test</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.security</groupId>
+            <artifactId>spring-security-test</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>
diff --git a/cannamanage-api/src/main/java/de/cannamanage/api/exception/GlobalExceptionHandler.java b/cannamanage-api/src/main/java/de/cannamanage/api/exception/GlobalExceptionHandler.java
new file mode 100644
index 0000000..ada43eb
--- /dev/null
+++ b/cannamanage-api/src/main/java/de/cannamanage/api/exception/GlobalExceptionHandler.java
@@ -0,0 +1,83 @@
+package de.cannamanage.api.exception;
+
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ProblemDetail;
+import org.springframework.security.access.AccessDeniedException;
+import org.springframework.security.authentication.BadCredentialsException;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+import java.net.URI;
+import java.time.Instant;
+
+/**
+ * Global exception handler producing application/problem+json responses.
+ * RFC 9457 compliant.
+ */
+@Slf4j
+@RestControllerAdvice
+public class GlobalExceptionHandler {
+
+    @ExceptionHandler(BadCredentialsException.class)
+    public ProblemDetail handleBadCredentials(BadCredentialsException ex) {
+        ProblemDetail problem = ProblemDetail.forStatusAndDetail(
+                HttpStatus.UNAUTHORIZED, "Invalid email or password");
+        problem.setTitle("Authentication Failed");
+        problem.setType(URI.create("urn:cannamanage:error:INVALID_CREDENTIALS"));
+        problem.setProperty("code", "INVALID_CREDENTIALS");
+        problem.setProperty("timestamp", Instant.now().toString());
+        return problem;
+    }
+
+    @ExceptionHandler(AccessDeniedException.class)
+    public ProblemDetail handleAccessDenied(AccessDeniedException ex) {
+        ProblemDetail problem = ProblemDetail.forStatusAndDetail(
+                HttpStatus.FORBIDDEN, "Access denied");
+        problem.setTitle("Forbidden");
+        problem.setType(URI.create("urn:cannamanage:error:ACCESS_DENIED"));
+        problem.setProperty("code", "ACCESS_DENIED");
+        problem.setProperty("timestamp", Instant.now().toString());
+        return problem;
+    }
+
+    @ExceptionHandler(MethodArgumentNotValidException.class)
+    public ProblemDetail handleValidation(MethodArgumentNotValidException ex) {
+        ProblemDetail problem = ProblemDetail.forStatusAndDetail(
+                HttpStatus.BAD_REQUEST, "Validation failed");
+        problem.setTitle("Bad Request");
+        problem.setType(URI.create("urn:cannamanage:error:VALIDATION_FAILED"));
+        problem.setProperty("code", "VALIDATION_FAILED");
+        problem.setProperty("timestamp", Instant.now().toString());
+
+        var fieldErrors = ex.getBindingResult().getFieldErrors().stream()
+                .map(fe -> fe.getField() + ": " + fe.getDefaultMessage())
+                .toList();
+        problem.setProperty("errors", fieldErrors);
+        return problem;
+    }
+
+    @ExceptionHandler(IllegalArgumentException.class)
+    public ProblemDetail handleIllegalArgument(IllegalArgumentException ex) {
+        ProblemDetail problem = ProblemDetail.forStatusAndDetail(
+                HttpStatus.BAD_REQUEST, ex.getMessage());
+        problem.setTitle("Bad Request");
+        problem.setType(URI.create("urn:cannamanage:error:BAD_REQUEST"));
+        problem.setProperty("code", "BAD_REQUEST");
+        problem.setProperty("timestamp", Instant.now().toString());
+        return problem;
+    }
+
+    @ExceptionHandler(Exception.class)
+    public ProblemDetail handleGeneric(Exception ex) {
+        log.error("Unhandled exception", ex);
+        ProblemDetail problem = ProblemDetail.forStatusAndDetail(
+                HttpStatus.INTERNAL_SERVER_ERROR, "An unexpected error occurred");
+        problem.setTitle("Internal Server Error");
+        problem.setType(URI.create("urn:cannamanage:error:INTERNAL"));
+        problem.setProperty("code", "INTERNAL_ERROR");
+        problem.setProperty("timestamp", Instant.now().toString());
+        return problem;
+    }
+}
diff --git a/cannamanage-api/src/main/java/de/cannamanage/api/security/JwtAuthFilter.java b/cannamanage-api/src/main/java/de/cannamanage/api/security/JwtAuthFilter.java
new file mode 100644
index 0000000..9d92187
--- /dev/null
+++ b/cannamanage-api/src/main/java/de/cannamanage/api/security/JwtAuthFilter.java
@@ -0,0 +1,82 @@
+package de.cannamanage.api.security;
+
+import de.cannamanage.domain.entity.TenantContext;
+import jakarta.servlet.FilterChain;
+import jakarta.servlet.ServletException;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
+import org.springframework.security.core.authority.SimpleGrantedAuthority;
+import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.security.web.authentication.WebAuthenticationDetailsSource;
+import org.springframework.stereotype.Component;
+import org.springframework.web.filter.OncePerRequestFilter;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.UUID;
+
+/**
+ * JWT authentication filter.
+ * Extracts Bearer token from Authorization header, validates it,
+ * sets SecurityContext and TenantContext for downstream processing.
+ */
+@Slf4j
+@Component
+@RequiredArgsConstructor
+public class JwtAuthFilter extends OncePerRequestFilter {
+
+    private final JwtService jwtService;
+
+    @Override
+    protected void doFilterInternal(HttpServletRequest request,
+                                    HttpServletResponse response,
+                                    FilterChain filterChain) throws ServletException, IOException {
+        final String authHeader = request.getHeader("Authorization");
+
+        if (authHeader == null || !authHeader.startsWith("Bearer ")) {
+            filterChain.doFilter(request, response);
+            return;
+        }
+
+        final String token = authHeader.substring(7);
+
+        if (!jwtService.isTokenValid(token)) {
+            filterChain.doFilter(request, response);
+            return;
+        }
+
+        UUID userId = jwtService.extractUserId(token);
+        UUID tenantId = jwtService.extractTenantId(token);
+        String role = jwtService.extractRole(token);
+
+        // Set tenant context for schema routing
+        TenantContext.setCurrentTenant(tenantId);
+
+        // Build authentication with role-based authority
+        var authorities = List.of(new SimpleGrantedAuthority("ROLE_" + role));
+        var authentication = new UsernamePasswordAuthenticationToken(
+                userId, null, authorities
+        );
+        authentication.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));
+
+        SecurityContextHolder.getContext().setAuthentication(authentication);
+        log.debug("Authenticated user {} for tenant {} with role {}", userId, tenantId, role);
+
+        try {
+            filterChain.doFilter(request, response);
+        } finally {
+            TenantContext.clear();
+        }
+    }
+
+    @Override
+    protected boolean shouldNotFilter(HttpServletRequest request) {
+        String path = request.getServletPath();
+        return path.startsWith("/api/v1/auth/")
+                || path.startsWith("/swagger-ui")
+                || path.startsWith("/v3/api-docs");
+    }
+}
diff --git a/cannamanage-api/src/main/java/de/cannamanage/api/security/JwtService.java b/cannamanage-api/src/main/java/de/cannamanage/api/security/JwtService.java
new file mode 100644
index 0000000..c6b5be9
--- /dev/null
+++ b/cannamanage-api/src/main/java/de/cannamanage/api/security/JwtService.java
@@ -0,0 +1,114 @@
+package de.cannamanage.api.security;
+
+import io.jsonwebtoken.Claims;
+import io.jsonwebtoken.Jwts;
+import io.jsonwebtoken.io.Decoders;
+import io.jsonwebtoken.security.Keys;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Service;
+
+import javax.crypto.SecretKey;
+import java.time.Instant;
+import java.util.Date;
+import java.util.Map;
+import java.util.UUID;
+import java.util.function.Function;
+
+/**
+ * JWT token generation and validation service.
+ * Access tokens: 1 hour expiry.
+ * Refresh tokens: 30 days expiry.
+ */
+@Service
+public class JwtService {
+
+    @Value("${cannamanage.security.jwt.secret}")
+    private String secretKey;
+
+    @Value("${cannamanage.security.jwt.access-token-expiry:3600}")
+    private long accessTokenExpiry; // seconds
+
+    @Value("${cannamanage.security.jwt.refresh-token-expiry:2592000}")
+    private long refreshTokenExpiry; // seconds (30 days)
+
+    public String generateAccessToken(UUID userId, UUID tenantId, String role, String email) {
+        return buildToken(Map.of(
+                "tenant_id", tenantId.toString(),
+                "role", role,
+                "email", email
+        ), userId.toString(), accessTokenExpiry);
+    }
+
+    public String generateRefreshToken(UUID userId, UUID tenantId) {
+        return buildToken(Map.of(
+                "tenant_id", tenantId.toString(),
+                "type", "refresh"
+        ), userId.toString(), refreshTokenExpiry);
+    }
+
+    public String extractSubject(String token) {
+        return extractClaim(token, Claims::getSubject);
+    }
+
+    public UUID extractUserId(String token) {
+        return UUID.fromString(extractSubject(token));
+    }
+
+    public UUID extractTenantId(String token) {
+        return UUID.fromString(extractClaim(token, claims -> claims.get("tenant_id", String.class)));
+    }
+
+    public String extractRole(String token) {
+        return extractClaim(token, claims -> claims.get("role", String.class));
+    }
+
+    public String extractEmail(String token) {
+        return extractClaim(token, claims -> claims.get("email", String.class));
+    }
+
+    public boolean isTokenValid(String token) {
+        try {
+            extractAllClaims(token);
+            return !isTokenExpired(token);
+        } catch (Exception e) {
+            return false;
+        }
+    }
+
+    public boolean isTokenExpired(String token) {
+        return extractExpiration(token).before(Date.from(Instant.now()));
+    }
+
+    private Date extractExpiration(String token) {
+        return extractClaim(token, Claims::getExpiration);
+    }
+
+    private <T> T extractClaim(String token, Function<Claims, T> resolver) {
+        final Claims claims = extractAllClaims(token);
+        return resolver.apply(claims);
+    }
+
+    private Claims extractAllClaims(String token) {
+        return Jwts.parser()
+                .verifyWith(getSigningKey())
+                .build()
+                .parseSignedClaims(token)
+                .getPayload();
+    }
+
+    private String buildToken(Map<String, Object> extraClaims, String subject, long expirySeconds) {
+        Instant now = Instant.now();
+        return Jwts.builder()
+                .claims(extraClaims)
+                .subject(subject)
+                .issuedAt(Date.from(now))
+                .expiration(Date.from(now.plusSeconds(expirySeconds)))
+                .signWith(getSigningKey())
+                .compact();
+    }
+
+    private SecretKey getSigningKey() {
+        byte[] keyBytes = Decoders.BASE64.decode(secretKey);
+        return Keys.hmacShaKeyFor(keyBytes);
+    }
+}
diff --git a/cannamanage-api/src/main/java/de/cannamanage/api/security/SecurityConfig.java b/cannamanage-api/src/main/java/de/cannamanage/api/security/SecurityConfig.java
new file mode 100644
index 0000000..6e48120
--- /dev/null
+++ b/cannamanage-api/src/main/java/de/cannamanage/api/security/SecurityConfig.java
@@ -0,0 +1,81 @@
+package de.cannamanage.api.security;
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.annotation.Order;
+import org.springframework.security.authentication.AuthenticationManager;
+import org.springframework.security.config.annotation.authentication.configuration.AuthenticationConfiguration;
+import org.springframework.security.config.annotation.method.configuration.EnableMethodSecurity;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
+import org.springframework.security.config.http.SessionCreationPolicy;
+import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
+import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.security.web.SecurityFilterChain;
+import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;
+
+/**
+ * Dual SecurityFilterChain configuration:
+ * - /api/** → stateless JWT (Bearer token)
+ * - /portal/** → session-based (future Sprint 3)
+ */
+@Configuration
+@EnableWebSecurity
+@EnableMethodSecurity
+@RequiredArgsConstructor
+public class SecurityConfig {
+
+    private final JwtAuthFilter jwtAuthFilter;
+
+    /**
+     * API security — stateless JWT authentication.
+     * All /api/v1/** endpoints require authentication except /api/v1/auth/**.
+     */
+    @Bean
+    @Order(1)
+    public SecurityFilterChain apiSecurityFilterChain(HttpSecurity http) throws Exception {
+        http
+                .securityMatcher("/api/**")
+                .csrf(csrf -> csrf.disable())
+                .sessionManagement(session -> session
+                        .sessionCreationPolicy(SessionCreationPolicy.STATELESS))
+                .authorizeHttpRequests(auth -> auth
+                        .requestMatchers("/api/v1/auth/**").permitAll()
+                        .requestMatchers("/api/v1/admin/**").hasRole("ADMIN")
+                        .requestMatchers("/api/v1/members/**").hasAnyRole("ADMIN", "STAFF")
+                        .requestMatchers("/api/v1/distributions/**").hasAnyRole("ADMIN", "STAFF")
+                        .requestMatchers("/api/v1/stock/**").hasAnyRole("ADMIN", "STAFF")
+                        .requestMatchers("/api/v1/reports/**").hasRole("ADMIN")
+                        .requestMatchers("/api/v1/compliance/**").hasAnyRole("ADMIN", "STAFF")
+                        .requestMatchers("/api/v1/me/**").authenticated()
+                        .anyRequest().authenticated())
+                .addFilterBefore(jwtAuthFilter, UsernamePasswordAuthenticationFilter.class);
+
+        return http.build();
+    }
+
+    /**
+     * Public endpoints — Swagger UI, actuator health.
+     */
+    @Bean
+    @Order(2)
+    public SecurityFilterChain publicSecurityFilterChain(HttpSecurity http) throws Exception {
+        http
+                .securityMatcher("/swagger-ui/**", "/v3/api-docs/**", "/actuator/health")
+                .csrf(csrf -> csrf.disable())
+                .authorizeHttpRequests(auth -> auth.anyRequest().permitAll());
+
+        return http.build();
+    }
+
+    @Bean
+    public PasswordEncoder passwordEncoder() {
+        return new BCryptPasswordEncoder();
+    }
+
+    @Bean
+    public AuthenticationManager authenticationManager(AuthenticationConfiguration config) throws Exception {
+        return config.getAuthenticationManager();
+    }
+}
diff --git a/cannamanage-api/src/main/resources/application.properties b/cannamanage-api/src/main/resources/application.properties
index 490d972..a65b2db 100644
--- a/cannamanage-api/src/main/resources/application.properties
+++ b/cannamanage-api/src/main/resources/application.properties
@@ -2,3 +2,14 @@ spring.application.name=cannamanage
 # Default profile — override with -Dspring.profiles.active=local
 spring.jpa.hibernate.ddl-auto=validate
 spring.flyway.enabled=false
+
+# JWT Security
+cannamanage.security.jwt.secret=Y2FubmFtYW5hZ2Utand0LXNlY3JldC1rZXktZm9yLWRldmVsb3BtZW50LW9ubHktMzI=
+cannamanage.security.jwt.access-token-expiry=3600
+cannamanage.security.jwt.refresh-token-expiry=2592000
+
+# OpenAPI
+springdoc.api-docs.path=/v3/api-docs
+springdoc.swagger-ui.path=/swagger-ui.html
+springdoc.swagger-ui.tags-sorter=alpha
+springdoc.swagger-ui.operations-sorter=method