docs: add observability, security, performance, and testing guides (#680)

Author: NanaKhadija1980j

Iss

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+Completed documentation work for the current backlog items.
+
+- Added testing and QA documentation in `docs/testing/index.md`
+- Added performance tuning and optimization guidance in `docs/performance/index.md`
+- Added security hardening and best practices documentation in `docs/security/index.md`
+- Added observability and monitoring guidance in `docs/observability/index.md`
+
+These guides implement the requested scope and deliverables for the four open backlog issues.

Issues.md

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+# Monitoring, Logging & Observability Guide
+
+This guide explains what to monitor, how to collect logs and metrics, and how to build useful dashboards and alerts for SoroScan.
+
+## Observability Strategy
+
+- Observe three pillars: metrics, logs, and traces.
+- Use RED (Rate, Errors, Duration) and USE (Utilization, Saturation, Errors) methods.
+- Define service-level objectives (SLOs) for availability and latency.
+
+## Metrics & Prometheus
+
+- Configure application metrics and export them to Prometheus.
+- Track key metrics such as request rate, error rate, latency, queue depth, and cache hit ratio.
+- Watch cardinality to prevent metric explosion.
+- Use PromQL to analyze service performance and build alerts.
+
+## Logging Strategy
+
+- Use structured logs for consistent fields and easier parsing.
+- Apply clear log levels: DEBUG, INFO, WARNING, ERROR, CRITICAL.
+- Aggregate logs in a central platform such as Loki, Elasticsearch, or hosted logging.
+- Define retention policies appropriate to support troubleshooting and compliance.
+
+## Distributed Tracing
+
+- Instrument services with OpenTelemetry or equivalent tracing libraries.
+- Configure trace sampling to balance visibility and cost.
+- Use traces to investigate latency, error propagation, and request flow.
+
+## Grafana Dashboards
+
+- Design dashboards for system health, API performance, and ingestion status.
+- Create a system health overview, request latency dashboard, and error trend dashboard.
+- Use alerts on key thresholds such as high error rate, request latency regression, or backend queue saturation.
+
+## Practical Observability
+
+- Monitor both infrastructure and application-level signals.
+- Correlate logs, metrics, and traces for faster root cause analysis.
+- Keep dashboards focused and actionable, with clear alert definitions.

docs/observability/index.md

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+# Performance Tuning & Optimization Guide
+
+This guide explains how to identify and fix performance bottlenecks across the full SoroScan stack.
+
+## Performance Profiling Tools
+
+- Django Debug Toolbar for request-level timing and SQL inspection.
+- Django Silk for request profiling and middleware tracing.
+- PostgreSQL `EXPLAIN ANALYZE` for query cost and plan analysis.
+- Redis monitoring with `redis-cli monitor`, `INFO`, and external dashboards.
+- Chrome DevTools, Lighthouse, and WebPageTest for frontend performance.
+
+## Database Optimization
+
+- Use indexes on frequently filtered and joined columns.
+- Prevent N+1 queries with `select_related` and `prefetch_related`.
+- Tune connection pooling and database timeouts in `DATABASE_URL`/`pgbouncer`.
+- Analyze slow queries using PostgreSQL logs and `EXPLAIN`.
+
+Example PostgreSQL query review:
+
+```sql
+EXPLAIN ANALYZE
+SELECT * FROM ingest_event WHERE contract_id = '...';
+```
+
+## Caching Strategy
+
+- Use Redis for frequently requested query results and API caches.
+- Design cache keys with versioning and time-based invalidation.
+- Cache database query results, computed dashboards, and endpoint responses.
+- Leverage HTTP caching headers for browser and CDN-level caching.
+
+## API Performance
+
+- Measure response times for REST and GraphQL endpoints.
+- Optimize pagination by limiting payload size and using cursor-based cursors.
+- Avoid expensive filtering operations on unindexed columns.
+- Use rate limiting to protect service availability while preserving performance.
+
+## Frontend Performance
+
+- Apply code splitting and lazy loading for heavy pages.
+- Optimize images, fonts, and build output bundle sizes.
+- Reduce client-side work on initial load and defer non-critical scripts.
+- Audit hydration and runtime performance with Lighthouse.
+
+## Monitoring Performance
+
+- Establish baselines for response time, throughput, and error rates.
+- Track performance trends in dashboards and alerts.
+- Use Grafana or equivalent tools for ongoing visibility.
+- Document before/after optimization results with metrics.
+
+## Practical Guidance
+
+- Start by profiling the slowest request path, then optimize incrementally.
+- Compare baseline metrics before and after changes.
+- Keep performance regressions visible in CI with targeted smoke tests.

docs/performance/index.md

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+# Security Best Practices & Hardening Guide
+
+This guide consolidates SoroScan's security approach across authentication, data protection, API hardening, infrastructure, and incident response.
+
+## Authentication & Authorization
+
+- Manage API keys with rotation and limited scopes.
+- Use JWT tokens only when appropriate, and store secrets securely.
+- Apply role-based access control (RBAC) for admin and ingestion operations.
+- Document permission boundaries and access tiers.
+
+## Data Protection
+
+- Enforce TLS for all external and internal traffic.
+- Protect sensitive fields at rest using environment-based encryption when required.
+- Keep secrets in environment variables or a secrets manager, never in source control.
+- Define data retention and privacy rules for PII and compliance-sensitive data.
+
+## API Security
+
+- Configure CORS to allow only trusted origins.
+- Enable CSRF protection for browser-based endpoints.
+- Validate and sanitize incoming request payloads.
+- Prevent SQL injection by using Django ORM and parameterized queries.
+- Apply rate limiting and DDoS protections on public endpoints.
+- Version APIs and include deprecation guidance for breaking changes.
+
+## Dependency Security
+
+- Scan dependencies regularly for vulnerabilities.
+- Use automated tools to identify supply-chain risks.
+- Keep dependencies up to date and apply security patches promptly.
+
+## Infrastructure Security
+
+- Harden network boundaries with firewalls and Kubernetes network policies.
+- Scan container images for known vulnerabilities.
+- Use secure secret management in Kubernetes and deployment pipelines.
+
+## Vulnerability Management
+
+- Maintain a vulnerability disclosure policy.
+- Define a clear bug reporting and triage process.
+- Apply security patches and track remediation progress.
+
+## Incident Response
+
+- Establish incident detection and alerting procedures.
+- Define an incident response playbook with roles and communication channels.
+- Conduct blameless post-incident reviews and update documentation.
+
+## References
+
+- Align guidance with OWASP Top 10 where applicable.
+- Include security checklist items for deployment and operations.

docs/security/index.md

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+# Testing & Quality Assurance
+
+This guide documents SoroScan's testing strategy across the backend, frontend, contracts, and end-to-end workflows.
+
+## Testing Strategy Overview
+
+- Testing pyramid: unit tests for fast validation, integration tests for subsystem behavior, end-to-end tests for full workflows.
+- Coverage goals: use targeted coverage metrics for critical business logic and key API surfaces.
+- Test data management: prefer fixtures, factories, and isolated database state.
+- Mocking and stubbing: mock external services and blockchain RPC responses while keeping contract and integration tests realistic.
+
+## Backend Testing Guide (Django)
+
+- Unit tests for models, views, serializers, helpers, and custom validators.
+- Integration tests for database-backed behavior and REST/GraphQL endpoints.
+- Celery task testing for webhook dispatch, retry behavior, and background ingestion.
+- `pytest` fixtures for reusable database state, authentication, and API clients.
+
+Example `pytest` unit test:
+
+```python
+from django.urls import reverse
+from rest_framework import status
+
+from soroscan.ingest.models import Event
+
+
+def test_event_serializer_creates_event(api_client, event_data):
+    url = reverse('event-list')
+    response = api_client.post(url, event_data)
+
+    assert response.status_code == status.HTTP_201_CREATED
+    assert Event.objects.filter(tx_hash=event_data['tx_hash']).exists()
+```
+
+Example fixture structure:
+
+```python
+import pytest
+from django.contrib.auth.models import User
+
+@pytest.fixture
+def api_client(client, django_user_model):
+    user = django_user_model.objects.create_user('tester', 'tester@example.com', 'pass')
+    client.force_login(user)
+    return client
+```
+
+## Frontend Testing Guide (Next.js / React)
+
+- Component testing with React Testing Library.
+- Hook testing for custom hooks and Apollo Client integration.
+- Page-level integration testing for component interactions and navigation.
+- MSW setup for mocking GraphQL and REST requests.
+- Jest configuration for snapshot testing and code coverage.
+
+Example component test:
+
+```tsx
+import { render, screen } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import EventCard from '@/components/EventCard';
+
+it('renders event fields and responds to click', async () => {
+  render(<EventCard event={{ id: '1', name: 'Transfer', block: 123 }} />);
+
+  expect(screen.getByText('Transfer')).toBeInTheDocument();
+  await userEvent.click(screen.getByRole('button', { name: /details/i }));
+  expect(screen.getByText(/block 123/i)).toBeVisible();
+});
+```
+
+## Contract Testing Guide (Rust)
+
+- Soroban contract unit tests for business logic and edge cases.
+- Contract integration tests that simulate transactions and external state.
+- Use the Soroban testing harness to verify emitted events and contract behavior.
+
+Example command:
+
+```bash
+cd soroban-contracts/soroscan_core
+cargo test
+```
+
+## End-to-End Testing Guide
+
+- Use Playwright to validate user workflows and API interactions.
+- Test scenarios for event ingestion, webhook delivery, and dashboard behavior.
+- Run full-stack E2E tests in CI to cover critical customer journeys.
+
+Example command:
+
+```bash
+pnpm exec playwright test
+```
+
+## Performance Testing
+
+- Load testing with `k6` or similar tools.
+- Baseline performance metrics for API throughput, latency, and ingestion.
+- Regression testing on key endpoints to detect performance drift.
+
+## Cross-Team Notes
+
+- Reference existing backend tests in `django-backend/`.
+- Reference frontend tests in `soroscan-frontend/__tests__/`.
+- Reference Soroban contract tests in `soroban-contracts/soroscan_core/`.