Make Your Applications Blazing Fast

What is Performance Engineering?

Performance engineering is a discipline focused on ensuring software applications meet their performance requirements throughout the development lifecycle. Unlike traditional performance testing—which often happens late in development—performance engineering embeds performance considerations from design through production.

Performance engineering encompasses analysis, design, implementation, testing, tuning, and monitoring of application performance. It's about building applications that are fast by design, not fast by accident. This proactive approach prevents performance problems rather than reacting to them after deployment.

At Salt, we approach performance engineering holistically—from frontend rendering to backend processing to database queries to infrastructure. We identify bottlenecks, implement optimizations, and establish monitoring so your applications stay fast as they evolve.

Key Performance Metrics

Performance engineering focuses on several key metrics:

• Response Time: How long it takes for a request to complete (usually measured in milliseconds)
• Throughput: Number of requests the system can handle per second (RPS)
• Latency: Time delay in the system, especially at various percentiles (p50, p95, p99)
• Error Rate: Percentage of requests that result in errors under load
• Resource Utilization: CPU, memory, disk, and network usage patterns
• Core Web Vitals: LCP, FID, CLS for frontend user experience

Types of Performance Testing

Different types of performance tests serve different purposes. A comprehensive performance engineering program uses multiple test types to understand how applications behave under various conditions.

Load Testing

Load testing validates that applications meet performance requirements under expected load. We simulate realistic user patterns and traffic volumes to verify response times, throughput, and resource utilization meet targets. Load tests answer: "Can we handle our expected traffic?"

Stress Testing

Stress testing pushes applications beyond normal operating capacity to identify breaking points. We gradually increase load until the system fails, revealing which component breaks first and how the system degrades. Stress tests answer: "What happens when we exceed our limits?"

Spike Testing

Spike testing validates behavior under sudden, dramatic traffic increases—like a marketing campaign going viral or a product announcement. We simulate rapid traffic surges to verify the system handles spikes gracefully. Spike tests answer: "Can we handle sudden traffic bursts?"

Soak Testing (Endurance Testing)

Soak testing runs applications under moderate load for extended periods to identify memory leaks, connection leaks, and gradual degradation. Problems that don't appear in short tests often surface during soak tests. Soak tests answer: "Does performance degrade over time?"

Capacity Testing

Capacity testing determines maximum capacity and helps with capacity planning. We identify how many users, transactions, or requests the system can handle while meeting performance requirements. Capacity tests answer: "How much can we handle?"

The Performance Engineering Process

Effective performance engineering follows a systematic process that produces measurable, sustainable improvements.

Phase 1: Assessment and Baselining

Every engagement starts with understanding current performance. We profile applications, analyze traces, and establish baseline metrics. This assessment identifies the biggest bottlenecks and opportunities. Without baselines, you can't measure improvement.

Phase 2: Goal Definition

Performance optimization without clear goals is inefficient. We work with stakeholders to define specific, measurable performance requirements: response time targets, throughput requirements, and scalability goals. These become our success criteria.

Phase 3: Test Design and Execution

We design test scenarios that simulate realistic user behavior—not just hitting endpoints randomly. User journeys, think times, and data patterns are modeled to produce meaningful results. Tests are executed in environments that match production.

Phase 4: Analysis and Optimization

Test results and profiling data guide optimization efforts. We prioritize fixes based on impact and effort—addressing the biggest bottlenecks first. Each optimization is measured against baselines to validate improvement.

Phase 5: Continuous Monitoring

Performance engineering doesn't end after optimization. We implement APM solutions for ongoing visibility and establish processes for continuous performance testing in CI/CD pipelines.

APM Implementation

Application Performance Monitoring (APM) provides real-time visibility into application health and performance. It's essential for catching issues before users notice them and for understanding production behavior.

Distributed Tracing

Modern applications span multiple services. Distributed tracing follows requests across service boundaries, showing exactly where time is spent. Tools like Jaeger, Zipkin, and OpenTelemetry provide this visibility, while platforms like Datadog and New Relic offer integrated tracing solutions.

Real-User Monitoring (RUM)

Synthetic tests don't capture real user experience. RUM measures actual user interactions—page load times, JavaScript errors, and Core Web Vitals—from real browsers. This data reveals performance variations across devices, browsers, and geographies.

Synthetic Monitoring

Synthetic monitoring runs scripted tests continuously from multiple locations. It catches availability and performance issues 24/7, even when no real users are active. Synthetic tests provide consistent baselines unaffected by traffic variations.

Alerting and SLOs

APM data powers alerting systems that notify teams when performance degrades. Service Level Objectives (SLOs) define acceptable performance, and alerts fire when SLOs are at risk. This enables proactive response before users are impacted.

Database Optimization

Databases are often the biggest performance bottleneck. A single slow query can bring an application to its knees. Database optimization delivers some of the largest performance gains.

Query Analysis and Optimization

We analyze query patterns, execution plans, and resource consumption to identify problematic queries. Optimization techniques include query rewriting, adding appropriate indexes, and denormalizing where beneficial. Sometimes the best optimization is not running the query at all.

Index Strategy

Proper indexing dramatically improves query performance but has trade-offs. We design index strategies that balance read performance against write overhead. Unused or redundant indexes are removed to reduce maintenance cost.

Connection Pooling

Database connections are expensive to establish. Connection poolers like PgBouncer for PostgreSQL maintain connection pools that applications share, reducing connection overhead and improving throughput.

Caching Strategies

The fastest query is the one you don't make. We implement caching at appropriate layers—application cache, distributed cache (Redis), and query result cache. Cache invalidation strategies ensure data freshness while maximizing cache hit rates.

Frontend Performance

Frontend performance directly impacts user experience and SEO rankings. Google's Core Web Vitals measure real user experience and affect search rankings. Optimizing frontend performance improves conversions and user satisfaction.

Core Web Vitals Optimization

Core Web Vitals—Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS)—measure user experience. We optimize for all three metrics through server-side rendering, asset optimization, and layout stability improvements.

Bundle Optimization

Large JavaScript bundles slow initial page load. We analyze bundles, implement code splitting, and configure tree shaking to reduce bundle sizes. Lazy loading defers non-critical code until needed.

Asset Optimization

Images often account for most page weight. We implement responsive images, modern formats (WebP, AVIF), and lazy loading. CSS is optimized, critical CSS is inlined, and unused CSS is removed.

CDN and Edge Caching

Content Delivery Networks serve static assets from locations close to users, reducing latency. Edge caching can cache dynamic content at the edge, reducing origin server load and improving global performance.

Common Performance Challenges

Understanding common performance challenges helps you recognize and address them in your applications.

N+1 Query Problems

N+1 queries occur when code fetches a list of items, then makes individual database queries for related data. This turns what should be 2 queries into N+1 queries. ORM eager loading and query batching solve this common problem.

Memory Leaks

Memory leaks cause gradual performance degradation and eventual crashes. Common causes include unclosed connections, growing caches without eviction, and event listener accumulation. Memory profiling identifies leak sources.

Thread Pool Exhaustion

When all threads are busy with slow requests, new requests queue or fail. This often cascades into complete application unavailability. Proper timeout configuration, circuit breakers, and thread pool sizing prevent exhaustion.

Inefficient Serialization

API response serialization can be surprisingly expensive. Over-fetching data, complex nested structures, and inefficient serializers add latency. Optimizing payloads and using efficient serialization improves API performance.

Performance Engineering Best Practices

These best practices, learned from hundreds of optimization projects, improve outcomes:

Establish Baselines First

Never optimize without measuring first. Establish clear baselines so you can prove improvements. "It feels faster" isn't a valid metric—you need numbers.

Profile Before Optimizing

Don't guess where bottlenecks are. Profile your application under realistic load to identify actual bottlenecks. Optimizing the wrong thing wastes effort and can make things worse.

Test with Production-Like Data

Performance with 100 records is very different from performance with 10 million. Use production-scale data volumes in testing. Anonymize if necessary, but maintain realistic volumes and distributions.

Optimize the Critical Path

Focus optimization efforts on the critical path—the user journeys and transactions that matter most. A 50% improvement in a rarely-used feature matters less than a 10% improvement in the checkout flow.

Monitor in Production

Production behavior differs from test environments. APM in production reveals real-world performance patterns, edge cases, and issues that don't appear in testing.

Make Performance Part of CI/CD

Catch performance regressions before they reach production. Automated performance tests in CI/CD pipelines with performance budgets prevent degradation from accumulating.

Why Salt for Performance Engineering?

Salt brings a differentiated approach to performance engineering. Here's what sets us apart:

Full-Stack Expertise: We optimize across the entire stack—from frontend rendering to backend processing to database queries to infrastructure. Performance problems rarely exist in isolation, and neither should solutions.

Measurable Results: We don't just say things are faster. Every engagement includes clear baselines, defined targets, and measured outcomes. You see exactly what improved and by how much.

Production-Focused: Lab performance means nothing if production is slow. We implement APM solutions and production monitoring so you have ongoing visibility—not just a one-time assessment.

Continuous Improvement: Performance engineering isn't a one-time project. We help you establish practices for continuous performance testing, monitoring, and optimization as your application evolves.

SPARK™ Delivery Framework: Our SPARK™ framework brings structure to performance engagements. Clear phases, quality gates, and success metrics ensure predictable delivery.

Knowledge Transfer: We don't just optimize—we teach. Every engagement includes documentation and training so your team understands the optimizations and can maintain performance independently.

Ready to make your applications blazing fast? Schedule a free assessment with our team to discuss your performance goals and how Salt can help you achieve them.