diff --git a/backend/src/auth/jwt.strategy.ts b/backend/src/auth/jwt.strategy.ts
new file mode 100644
index 0000000..b2a1882
--- /dev/null
+++ b/backend/src/auth/jwt.strategy.ts
@@ -0,0 +1,30 @@
+import { Injectable } from '@nestjs/common';
+import { PassportStrategy } from '@nestjs/passport';
+import { ExtractJwt, Strategy } from 'passport-jwt';
+import { passportJwtSecret } from 'jwks-rsa';
+
+@Injectable()
+export class JwtStrategy extends PassportStrategy(Strategy) {
+  constructor() {
+    super({
+      jwtFromRequest: ExtractJwt.fromAuthHeaderAsBearerToken(),
+      ignoreExpiration: false,
+      secretOrKeyProvider: passportJwtSecret({
+        cache: true,
+        rateLimit: true,
+        jwksRequestsPerMinute: 5,
+        jwksUri: `${process.env.KEYCLOAK_URL}/protocol/openid-connect/certs`,
+      }),
+      algorithms: ['RS256'],
+      issuer: process.env.KEYCLOAK_URL,
+    });
+  }
+
+  validate(payload: any) {
+    return {
+      userId: payload.sub,
+      username: payload.preferred_username,
+      roles: payload.realm_access?.roles ?? [],
+    };
+  }
+}