The article explains how Event Sourcing stores immutable, ordered events instead of the current state, details aggregate rehydration, snapshots, and projections, clarifies its orthogonal relationship with CQRS and DDD, and debunks four common misconceptions about the pattern.
This article compiles over thirty detailed architecture diagrams covering Java class loaders, JVM, Spring, Hibernate, Android, Linux kernel, cloud computing, and various enterprise technologies, offering developers a visual reference library for understanding and designing Java backend systems.
The article argues that modern backend systems inevitably hit a scalability wall, and the most effective way to cross it is to use Go for fast, simple service orchestration while delegating performance‑critical, resource‑intensive components to Rust, combining both languages to balance development speed, cost, and reliability.
The article revisits the heated debate sparked by AWS evangelist James Ward, who argues that Go’s concurrency primitives are inferior to the JVM’s virtual threads, structured concurrency, and effect systems, using a demanding connection‑pool challenge to illustrate the trade‑offs and guide architects in choosing the right model for their workloads.
The article examines a minimal 30‑minute Agent loop demo, then analyzes how Harness can serve as the backend by introducing a runtime capability registry, worker lifecycle management, diverse triggers, and unified tracing, outlining four concrete design actions to close the gaps for agent‑ready systems.
The article explains that Nginx and Spring Cloud Gateway serve different roles—Nginx as a network gateway handling static files, load balancing, SSL termination, and ops tasks, while Gateway focuses on business routing—so using both together improves performance, scalability, and operational separation.
Facing explosive merchant growth and soaring order volumes, JD redesigned its B‑side POP order storage by isolating large tenants, applying double‑hash routing, expanding clusters, buffering updates, and automating data archiving, ultimately delivering a high‑performance, scalable Elasticsearch platform that sustains massive traffic spikes.
This article dissects Claude Code’s Memory subsystem, explaining the distinction between Session logs and persistent Memory, the SHA‑256‑based storage layout, file indexing, four memory types, prompt injection steps, two write pathways, the ExtractionCoordinator’s coalescing strategy, and how to explain the design in interviews.
The article compares Layer‑4 and Layer‑7 load‑balancing solutions for million‑concurrency scenarios, outlining their use cases, advantages, typical tools, performance characteristics, and why large enterprises often combine both to achieve high stability and flexible traffic control.
This comprehensive guide explains the purpose, core concepts, suitable scenarios, common patterns, benefits, and potential pitfalls of asynchronous processing, offering detailed design, development, review, and operational principles to help teams build reliable, high‑throughput systems.
The article breaks down the complexities of payment processing by outlining business background, decomposing the workflow into modular steps, illustrating sequence diagrams, designing data structures, and addressing related domains such as product and coupon management, while highlighting key technical challenges like TCC transactions, locking, and retry mechanisms.
This article explains why Function Calling requires a robust server‑side architecture, walks through a real e‑commerce use case, details the Go‑based protocol, modular design, concurrency handling, security, observability, deployment strategies, testing approaches, and a step‑by‑step roadmap for turning a demo into a production‑grade system.
This article provides a comprehensive overview of microservice architecture, outlining its core goals, design principles, and a wide range of decomposition, integration, database, event‑driven, observability, and cross‑cutting concern patterns, complete with practical examples and diagrams.
The article chronicles the step‑by‑step evolution of a small team’s chaotic food‑delivery backend into a production‑ready system, detailing how they introduced layering, transactions, security, caching, async processing, messaging, observability, scalability, resilience, containerization, and testing using Spring Boot, Kafka, Redis, JWT, and Docker.
The article explains why a single‑module SpringBoot project becomes problematic as business complexity grows, outlines the benefits of a multi‑module architecture—including clear responsibilities, high cohesion, faster compilation, and smoother microservice migration—and provides a step‑by‑step guide with Maven configuration, module responsibilities, code examples, packaging commands, and common pitfalls.
This article analyzes the growing complexity of a distributed microservice platform and presents three isolation strategies—application splitting, Hystrix thread‑/semaphore isolation, and a lightweight process‑level grouping approach—detailing their implementation, trade‑offs, and practical results for high‑traffic promotions.
This article explains how combining Go, PostgreSQL, and sqlc creates a Zero‑ORM architecture that restores SQL to the center of high‑performance, highly controllable, and maintainable backend services, covering design principles, layer responsibilities, schema and query patterns, connection‑pool tuning, transaction handling, observability, and practical best‑practice checklists.
The article explains why many developers get stuck when moving from writing business code to system design, outlines a step‑by‑step engineering learning path that covers core components, hands‑on examples, trade‑off analysis, interview preparation, and communication techniques to build a holistic system‑design mindset.
The article dissects Alibaba’s second‑round interview question on handling 10 million daily order queries, exposing why a single sharding answer fails and presenting a comprehensive architecture‑seven‑suite combined with heterogeneous storage (MySQL, HBase, ClickHouse, ES, Redis, MQ) to achieve high concurrency, low latency, and reliable data consistency.
This article explores how to model clean, high‑cohesion Go structs using Domain‑Driven Design, value objects, entities, services, and proven patterns like functional options, builders, specifications, and repositories, illustrated with e‑commerce and payment system examples.
This article explores a series of unconventional yet practical caching designs—including consistent hashing with local caches, request‑scope caching, session‑level caching, client‑side caching, pre‑loading, and graceful degradation—to dramatically improve backend response times, reliability, and interview impact.
This article walks through the step‑by‑step evolution of a large‑scale e‑commerce backend—from a single‑server setup to microservices, containerization, and cloud platforms—highlighting the technical challenges, key technologies, and design principles that enable millions of concurrent users.
This article surveys common microservice design patterns—including decomposition, integration, event‑driven, cross‑cutting concerns, and observability—explaining their goals, trade‑offs, and practical implementation steps to help architects build scalable, resilient backend systems.
The article explains how excessive if‑else branching in multi‑business systems harms code maintainability, and demonstrates how a workflow engine combined with a plugin extension mechanism can isolate business logic, simplify testing, and enable flexible execution chains, using the open‑source MemberClub project as a concrete example.
This article explains how separating static and dynamic traffic with Nginx, configuring precise location rules, cache headers, and kernel optimizations can increase throughput by three to five times in high‑concurrency web architectures while reducing backend load and improving maintainability.
The article reviews the newly released GLM-5 model, highlighting its ability to generate end‑to‑end system designs, write and debug backend code, and solve large‑scale engineering problems through detailed prompts, positioning it alongside GPT‑5.3 and Claude Opus in the competitive LLM landscape.
The article explains how excessive if‑else logic harms maintainability in a business middle‑platform, introduces a flow‑engine and plugin‑extension approach to isolate code and support rapid business expansion, and demonstrates the design with the open‑source MemberClub project, including configuration, node definitions, execution principles and core Java implementation.
The article explains why design patterns often feel useless in Spring Boot projects, introduces a three‑branch decision tree that maps common sources of complexity to suitable patterns, and demonstrates a concrete refactor of an if‑else payment service into a clean, Spring‑managed strategy‑based solution.
LiteFlow is a lightweight, open‑source Chinese rule engine that transforms tangled if‑else code into modular, hot‑deployable components using a simple EL DSL, offering high performance, multi‑language scripting, and visual orchestration for backend systems.
This article explains why microservices, while attractive for large systems, introduce hidden costs, operational complexity, network latency, data management challenges, and testing difficulties, and provides a decision framework to determine when a monolith‑first approach is more appropriate.
This article details a comprehensive redesign of a high‑traffic order system, covering the challenges of massive data volume, concurrency pressure, and poor scalability, and presenting a step‑by‑step solution that includes sharding strategy selection, database product comparison, unique ID generation, middleware choice, migration plan, risk mitigation, and FAQ handling.
This guide breaks down a real‑world interview scenario where a backend engineer must design a scalable database solution for a billing‑log or feed system handling 100 million daily inserts and 100 k QPS reads, covering partitioning vs sharding, sharding key selection, shard count, read‑write separation, multi‑level caching, consistency patterns, hot‑key mitigation, and online schema changes.
This article explains how e‑commerce flash‑sale systems handle extreme concurrency by defining TPS requirements for different scales, applying a layered filtering architecture, and using techniques like CDN caching, rate limiting, Redis pre‑deduction, and minimal database writes to ensure stability.
This article walks through the layered architecture that large services like Instagram use to instantly check if a username is taken, starting from simple database queries, adding caching, employing Bloom filters, and finally using Trie structures for fast, memory‑efficient lookups.
The article explains the limitations of Spring MVC's blocking model, introduces Spring WebFlux's reactive, asynchronous, non‑blocking architecture, compares annotation and functional programming models, details core components and request flow, and provides guidance on when and how to adopt WebFlux for high‑concurrency I/O‑intensive applications.
In complex systems where multiple modules must cooperate, asynchronous communication boosts throughput but often becomes a black box, so this article outlines three async patterns, their trade‑offs, and a comprehensive monitoring, alerting, and remediation framework for reliable operation.
This article examines how business scale and system boundaries evolve, explaining when hooks are optimal, why they become problematic, and how to transition smoothly to event‑driven architectures with concrete examples, signals, and a step‑by‑step migration path.
This article recounts the migration from a simple HTTP polling approach to an MQTT‑based real‑time communication architecture, detailing the motivations, technical comparisons, implementation steps, performance gains, operational challenges, and future directions for scalable event‑driven systems.
The article traces the evolution from monolithic Java apps to RPC services, explains why sharding and database partitioning cannot alone achieve limitless scaling due to connection limits, and introduces unitization—assigning each application to a specific database shard—to overcome the bottleneck.
This article provides a comprehensive framework for evaluating system support capability by defining QPS excellence thresholds across industry benchmarks, business types, response time, resource efficiency, performance metrics, architectural guidelines, optimization tactics, and real‑world case studies, culminating in a practical calculation formula.
This article dissects a common interview question about automatically canceling unpaid orders after 30 minutes, explains why naive cron jobs fail at scale, and presents three robust backend designs—Redis ZSet polling, message‑queue delayed messages, and time‑wheel timers—along with practical code snippets and pitfalls to avoid.
The article analyzes a common Java interview question about using JOINs, explaining performance bottlenecks, scalability issues in distributed and micro‑service architectures, and offers practical guidelines and best‑practice alternatives for handling data associations efficiently.
The article explains how excessive if‑else branching in business‑centered back‑ends leads to tangled, hard‑to‑maintain code, and demonstrates how a flow‑engine combined with plugin extensions can isolate business logic, improve extensibility, and simplify testing, using the open‑source MemberClub project as a concrete example.
Netflix built a distributed write‑ahead log (WAL) system to guarantee data consistency, durability, and high‑throughput across services, tackling challenges like data loss, cross‑store entropy, multi‑partition updates, replication, and reliable retry for real‑time pipelines.
This case study shows how AI was used to analyze a monolithic service‑package system, automatically identify bounded contexts, generate DDD‑aligned code skeletons, and refactor duplicated business logic, reducing development effort from 5‑8 person‑days to a configurable solution while improving maintainability and extensibility.
This article explains how Ctrip’s Universal Control Service (UCS) handles global traffic routing, data‑compliance zones, region failover, and gradual migration by using configurable strategy models, partitioning logic, and a lightweight degradation mask to ensure reliable, compliant user experiences worldwide.
This guide explains how to design a high‑performance Nginx architecture that can handle up to half a million concurrent requests, covering horizontal scaling, OS and hardware tuning, critical Nginx directives, and complementary optimization techniques.
This article analyzes Bilibili's private messaging architecture, identifies performance bottlenecks such as MySQL slow queries, storage limits, and tightly coupled services, and presents a multi‑layer redesign with caching, sharding, BFF separation, and consistency mechanisms to sustain tenfold traffic growth.
This article explains how the agent-web framework builds a powerful AI agent orchestration system in Go without external libraries, detailing the reasons for choosing Go, the use of go:embed for single‑binary deployment, core data structures, planning and execution logic, and the interaction handling that enables both CLI and web interfaces.
This article explains the principle of Nginx static‑dynamic separation, describes its layered architecture, request routing flow, and key optimization techniques such as caching, compression, load balancing, security limits, and monitoring to dramatically improve overall system performance.
This article explains the fundamentals of distributed communication, outlines essential elements such as serialization, transport protocols, service discovery, load balancing, security, and reliability, and reviews popular frameworks like gRPC, Dubbo, Thrift, and OpenFeign for building robust backend architectures.
This article dissects the core processes, functional challenges, and architectural design of a high‑throughput, strongly consistent e‑commerce order system, covering forward and reverse flows, order creation, payment, fulfillment, cancellation, after‑sale handling, and the layered backend architecture that powers it.
This article provides a comprehensive overview of RocketMQ, covering its core components (Producer, Broker, Consumer, NameServer), detailed architecture diagrams, step‑by‑step message production and consumption processes, and typical scenarios such as asynchronous decoupling, traffic shaping, transactional messaging, and event‑driven logging.
This article compares microservices and SOA, covering design philosophy, service granularity, autonomy, communication mechanisms, and deployment/operations, highlighting how microservices favor lightweight protocols, independent deployment, and container orchestration, while SOA relies on centralized middleware and coarse‑grained services.
To ensure fund safety and robust operations, the team built a real‑time reconciliation platform that leverages Kafka, and after encountering scaling bottlenecks with a static consumer model, they implemented a dynamic, partition‑level, weighted load‑balancing consumer cluster that supports automatic scaling and high‑throughput processing.
This article explains how to build a production‑grade short‑link service, covering the background of SMS short URLs, Base62 encoding principles, database schema design, request routing, security measures such as custom alphabets, rate limiting, and signed links, and additional management features for operation and monitoring.
This article presents a comprehensive guide to essential system‑design concepts—including client‑server architecture, IP addressing, DNS, proxies, latency, HTTP/HTTPS, APIs, REST, GraphQL, databases, scaling, caching, microservices, message queues, rate limiting, API gateways, and more—illustrated with Spring Boot 3 examples and diagrams.
During peak travel periods, 12306 often displays available seats that cannot be booked, a problem caused by intricate inventory deduction across multiple travel segments, heavy caching strategies, and real‑time load pressures that lead to stale data and purchase failures.
This article chronicles the decade‑long evolution of WeChat Reading’s backend, detailing architectural layers, RPC framework innovations, storage migrations, account system redesign, book data platform construction, and modern content retrieval techniques that together enable high availability and scalability.
Designing high‑traffic, high‑concurrency systems requires careful planning across architecture, client optimization, CDN usage, clustering, caching, database tuning, and service governance, with principles such as statelessness, modularity, and fault‑tolerance to ensure scalability, reliability, and maintainability.
An in‑depth guide to microservice architecture explores its evolution, core characteristics, advantages and drawbacks, and walks through essential design patterns—Database per Service, Event Sourcing, CQRS, Saga, BFF, API Gateway, Strangler, Circuit Breaker, Externalized Configuration, and Consumer‑Driven Contract Testing—detailing when and why to use each.
This article details how Vivo Browser's welfare center was re‑engineered—splitting services, sharding databases, adding arbitration and soft‑transaction mechanisms—to overcome traffic, I/O, and data‑consistency challenges, enabling stable operation at tens of millions of daily active users while reducing storage costs.
This article walks through a complete, interview‑ready design of a high‑performance rate‑limiting system that can handle up to one million queries per second, covering requirements, core entities, algorithm choices, distributed state storage with Redis, scalability, high availability, latency optimization, hot‑key mitigation, and dynamic rule configuration.
This article walks through the complete design of a high‑performance, highly available URL shortener—covering business value, requirement analysis, capacity estimation, API definitions, database schema, key generation algorithms, sharding, caching, load balancing, and expiration cleanup—so you can impress interviewers with a thorough, scalable solution.
This article examines the data dependency challenges among microservices in a supply‑chain system, compares initial data‑redundancy and decoupled synchronization approaches, and demonstrates how real‑time table sync using the open‑source Bifrost middleware can improve query performance and maintain consistency.
This article explains how to evaluate system performance bottlenecks, choose between hard and soft rate‑limiting, and implement a non‑intrusive, high‑concurrency traffic‑control solution using OpenResty, Lua scripts, and Redis, covering architecture design, queue management, rate limiting, resource release, and performance testing.
This article examines why many DDD projects default to anemic models, identifies scenarios where DDD adds real value, and provides practical strategies—including aggregate redesign, event‑driven consistency, and incremental refactoring—to successfully implement Domain‑Driven Design in complex backend systems.
This article outlines ten practical microservice best practices—including single responsibility, cross‑functional teams, proper tooling, asynchronous communication, DevSecOps, independent data stores, isolated deployment, orchestration, and monitoring—to help developers build scalable, maintainable, and secure backend systems.
This article explains how to design a high‑availability, million‑level concurrent architecture using LVS for layer‑4 load distribution, Nginx for intelligent application‑layer routing, and Keepalived for automatic failover, illustrated with clear diagrams and practical insights.
This article explains how to select and combine hardware, software, and cloud load‑balancing solutions—such as F5 BIG‑IP, Nginx, LVS, and public‑cloud SLB—to achieve optimal stability and performance in high‑concurrency environments.
This article dissects the architecture of a modern short‑video backend, covering layered system design, core services such as video production, distribution, interaction, storage strategies, real‑time and offline recommendation engines, high‑concurrency streaming solutions, and practical techniques for cost control, scalability, and fault tolerance.
This article explains the fundamentals of distributed transactions, illustrates why they are essential for multi‑service operations such as e‑commerce order processing, and compares four major solutions—two‑phase commit, three‑phase commit, TCC, and message‑queue based eventual consistency—detailing their workflows, advantages, and drawbacks.
This article explores a step‑by‑step evolution of business operation logging—from a simple AOP‑annotation approach, through enriched SpEL expressions, to a robust Binlog‑based solution with time‑window aggregation—highlighting benefits, challenges, code examples, and architectural diagrams for backend developers.
This article compares Nginx and Apache architectures, explaining how Nginx’s event‑driven, single‑threaded workers handle thousands of simultaneous connections with minimal resources, while Apache’s process‑oriented models consume more CPU and memory under heavy load.
This article details Bilibili's third‑generation streaming transcoding system, explaining its architecture, core modules, testing strategies, quality‑assurance plans, and code examples that together dramatically reduce processing time and support millions of daily video uploads.
This article dissects the end‑to‑end payment workflow, identifies performance, reliability and data‑consistency bottlenecks across order creation, risk assessment, routing, settlement and payout stages, and presents concrete architectural patterns, code snippets and monitoring strategies to achieve sub‑second latency and 99.99% availability under massive traffic spikes.
This article explains the three types of IM packets—Request, Acknowledge, and Notify—illustrates the basic message flow between client and server, identifies reliability gaps such as lost notifications, and proposes an application‑level solution using acknowledgments, timeout‑driven retransmission, and message deduplication to achieve dependable delivery.
This article examines ten typical problems encountered when adopting microservices—such as improper service splitting, distributed transaction failures, configuration chaos, logging fragmentation, database sharing, API incompatibility, CI bottlenecks, monitoring gaps, and team collaboration issues—and provides concrete solutions, best‑practice principles, code examples, and architectural guidelines to help engineers build reliable, maintainable microservice systems.
This article shares ten frequent microservice problems—from improper service splitting and distributed transaction failures to configuration chaos, logging fragmentation, database sharing, API incompatibility, CI bottlenecks, missing monitoring, and team collaboration issues—offering concrete solutions, best‑practice principles, and code examples to help engineers build robust, maintainable microservice systems.
This article explores the four‑layer load‑balancing architecture, five common algorithms (including Round Robin, Weighted RR, Least Connections, Consistent Hashing, and AI‑driven adaptive load), high‑availability design, deep pitfalls, and a self‑built load balancer implementation, providing practical code examples and best‑practice guidelines.
This article details the design of a reusable, configurable lottery platform for a youth‑focused social app, covering business background, pain points, a modular data model, micro‑service architecture, stock pre‑allocation with optimistic and distributed locks, real‑time risk detection, over‑issue prevention, probability calculation, and future AI‑driven enhancements.
This article explains why RPC should be used when callers need immediate results, why forcing MQ for request‑response adds complexity and risk, and how combining RPC for result‑sensitive flows with MQ for fire‑and‑forget events achieves clean architectural decoupling.
This article explains what a process engine is, distinguishes workflow from BPM, explores common design patterns for process designers, organization structures, form and page design, and presents a detailed architecture guide with code examples and commercial opportunities for building robust backend workflow solutions.
Understanding system design trade‑offs is crucial for building robust software; this article examines ten common compromises—from vertical vs. horizontal scaling and SQL vs. NoSQL to CAP theorem, consistency models, REST vs. GraphQL, stateful vs. stateless architectures, caching strategies, and synchronous vs. asynchronous processing—highlighting their benefits and drawbacks.
Payment systems serve as the essential bridge linking consumers, merchants, and financial institutions in e‑commerce, handling everything from transaction processing and security compliance to multi‑channel payment management, order settlement, refunds, and detailed architecture design that evolves from closed internal apps to open, scalable micro‑service platforms.
This article details the design and implementation of a high‑performance data‑screen platform, covering its background, functional matrix, cloud‑native architecture, caching strategies, resource isolation, load testing, and monitoring, and demonstrates how it supports over 500 concurrent screens with sub‑second response times for enterprise decision‑making.
Microservices have become the standard architecture for large internet companies, offering superior scalability, maintainability, and team autonomy compared to monolithic systems, while demanding a broad tech stack—including service discovery, API gateways, container orchestration, and distributed transaction handling—making expertise in this area highly lucrative.
This article explains how to refactor a monolithic dependency‑injection container into separate repository, service, and application containers, aligning with the Single Responsibility Principle, improving maintainability, testability, and limiting change ripple effects within clear architectural boundaries, with full Python/FastAPI code examples.
The article explains how over‑design can be avoided by using workflow orchestration and plugin extensions to isolate business logic, reduce if‑else sprawl, and improve extensibility, illustrated with the open‑source MemberClub project and its Java flow‑engine implementation.
This article outlines the key building blocks of a microservice architecture—including Nginx as the traffic entry, Spring Cloud Gateway, service registries, Redis caching, MySQL persistence, Elasticsearch, message queues, ELK logging, distributed schedulers, and object storage—explaining their roles, deployment patterns, and common technology choices.
This article examines common interview scenarios involving distributed locks, explains why they are often misused, outlines their proper use cases such as rate limiting, ensuring data consistency, and achieving ordered processing, and compares distributed locks with distributed transactions.
Marking ten years of WeChat Reading, this article details the backend's evolution from a monolithic service to a multi‑layered, micro‑service architecture with robust storage, RPC frameworks, book data platforms, account system redesign, and AI‑driven content retrieval, highlighting the technical challenges and solutions behind its scalability.
Splitting a monolith into microservices can shift complexity to inter‑service communication, causing data consistency issues and CAP trade‑offs, so you must evaluate motivations, apply single‑responsibility and team‑aligned boundaries, and follow practical guidelines to ensure a sound architecture.
This article examines the evolution of permission frameworks in digital systems, explains functional, data, and approval permissions, and compares four concrete data‑permission implementations, highlighting their trade‑offs and presenting a refined model that balances role management with fine‑grained data access.
This article outlines a comprehensive, step‑by‑step roadmap for preparing system design interviews, covering foundational concepts, interview templates, high‑level and detailed design choices, practical resources, mock interview platforms, and company‑specific tailoring to boost candidates' success.
The article explains why RPC should be used when callers need immediate results, while MQ is preferable for fire‑and‑forget notifications, illustrating the trade‑offs with code examples, common pitfalls of misusing each method, and practical steps to achieve physical and logical decoupling in backend systems.
This article explains multi‑tenancy as a software architecture pattern, describes why it reduces operational costs and improves resource utilization, and presents five concrete SpringBoot designs—including separate databases, shared databases with separate schemas, shared tables, shared‑table with tenant ID, and a hybrid model—along with implementation steps, code samples, pros and cons, and suitable scenarios.
This article explores how DeWu's community activity platform evolved from ad‑hoc implementations to a componentized, event‑driven backend using OOP principles, modular design, rule engines, and observer‑hook mechanisms, while also outlining future AI‑driven optimizations and system‑wide standardization.
This article explains how to build a high‑availability, million‑level concurrent architecture by combining Linux Virtual Server (LVS) for layer‑4 load balancing, Nginx for layer‑7 reverse proxy and caching, and Keepalived for VIP failover, including configuration examples and deployment modes.
This article outlines practical microservice best practices—including the Single Responsibility Principle, cross‑functional teams, appropriate tooling, asynchronous communication, DevSecOps, isolated data stores, independent deployment, orchestration, and monitoring—to help developers build maintainable, scalable, and secure cloud‑native applications.
