back_end_oudelaa/docs/SYSTEM_STRENGTH_REPORT.md

System strength report

Date: 2026-07-22

Result

The backend is functionally stable and performs well in the tested local environment. It is not yet possible to claim production-scale capacity because the test used a single Node.js process, local MongoDB, a small dataset, and disabled Redis/S3/Atlas dependencies.

Verification summary

Area	Result
TypeScript build	Passed
ESLint	Passed
Unit/integration suites	85/85 passed
Unit/integration tests	947/947 passed
End-to-end scenarios	14/14 passed
Dependency audit	0 cached advisory findings; live audit runs in CI
Statement coverage	93.08%
Branch coverage	67.97%
Function coverage	92.93%
Line coverage	93.26%

The executable service layer is also protected by an aggregate coverage gate: 92.81% statements, 93.02% lines, 93.67% functions, and 74.96% branches across 43 service files. npm run test:coverage enforces both the project-wide gates and these service-layer gates, and the same command is mandatory in CI.

Performance results

Tests ran on one local process and are useful for regression comparison, not public capacity promises.

Workload	Concurrency	Throughput	Average	p95	p99	Success
Liveness health	20	2357 req/s	8.47 ms	12.64 ms	15.92 ms	100%
Cached personalized feed	20	567 req/s	35.20 ms	40.78 ms	45.25 ms	100%
Liveness burst	100	2448 req/s	40.71 ms	48.89 ms	72.62 ms	100%
Uncached personalized feed	20	65 req/s	304.34 ms	392.81 ms	445.92 ms	100%
Uncached compatibility search	10	109 req/s	91.38 ms	100.38 ms	106.79 ms	100%
Hardened health gate	50	2041 req/s	24.40 ms	39.85 ms	48.57 ms	100%
Cold-cache/coalesced feed gate	30	336 req/s	88.79 ms	116.14 ms	168.69 ms	100%

Cold startup was approximately 4.8 seconds.

Security checks

• Forged JWT was rejected with 401.
• NoSQL-shaped login input was rejected with 400.
• Unknown privileged fields were rejected with 400.
• Malformed JSON was rejected with 400.
• A request above the configured body limit was rejected with 413.
• Login throttling returned 429 after the allowed attempts were consumed.
• Production CORS returned the configured origin and did not return an allow-origin header for an untrusted origin.
• HSTS, X-Frame-Options, X-Content-Type-Options, and Referrer-Policy were present in production mode.
• The npm audit reported zero known vulnerabilities.

Concurrency and realtime checks

• Twenty simultaneous duplicate like requests produced one like and a correct counter.
• Authenticated Socket.IO clients connected to both chat and notifications namespaces.
• An anonymous Socket.IO client was disconnected.
• Refresh-token rotation, notification delivery, feed exclusion, comments, uploads, and superadmin sessions passed end-to-end.

Improvements made during testing

• Added /api/v1/health/ready, which checks MongoDB, Redis when enabled, and storage, and returns 503 when degraded.
• Added readiness unit and end-to-end coverage.
• Added real Socket.IO end-to-end tests.
• Added concurrent idempotency coverage for likes.
• Improved startup benchmark diagnostics to include the child exit code and recent logs.
• Corrected local storage configuration to use direct media access.
• Added local single-flight and ownership-safe Redis leases to prevent cache stampedes.
• Added configurable MongoDB connection pools and disabled automatic production index builds by default.
• Added response compression and bounded Node HTTP transport settings.
• Added request deadlines, graceful request draining, and drain-aware readiness.
• Added event-loop, in-flight request, timeout, and bounded-cardinality route metrics.
• Added direct, user-scoped S3 PUT uploads so large media can bypass Node memory.
• Added CI performance gates and made unit, E2E, audit, and Docker build checks mandatory before deployment.
• Added behavioral, security, failure-path, controller-delegation, repository-persistence, and bootstrap tests, increasing the regression suite to 947 tests.
• Added enforced project-wide and service-layer coverage gates so the achieved baseline cannot silently regress.
• Hardened the production container with a non-root user, tini, a healthcheck, and secret-safe Docker context exclusions.

Remaining production validation

Before a high-traffic launch, run the same tests in staging with production-sized data and production topology:

1. Multiple application replicas behind the real load balancer.
2. Redis enabled for cache, throttling, queues, and Socket.IO fan-out.
3. S3-compatible storage, signed media URLs, and CDN behavior.
4. Atlas Search indexes and representative Arabic/English datasets.
5. Long soak tests (2-8 hours), failover tests, and MongoDB/Redis latency injection.
6. Continue raising branch coverage, prioritizing rare infrastructure and dependency-failure combinations.
7. Run an external DAST/SAST and penetration test before handling sensitive production data.

Current assessment

• Functional correctness: strong.
• Local performance: strong with cache; acceptable but database-bound without cache.
• Security controls: strong baseline.
• Operational readiness: good after adding dependency readiness checks.
• Automated test maturity: strong baseline, with more than 90% statement, line, and function coverage plus separate runtime-service gates.
• Production-scale confidence: pending staging tests with real infrastructure and data volume.