Author
Ahmadullah Mukhlis
Full-stack and fintech software engineer writing about payment systems, enterprise applications, mobile and web development, APIs, cloud infrastructure, and production software architecture.
Articles
ISO 8583 Explained: Complete Guide to Payment Message Structure and Transaction ProcessingISO 8583 MTI Explained: Understanding Message Type IndicatorsISO 8583 Data Elements Explained: A Practical Field-by-Field GuideISO 8583 Response Codes: How Transaction Results Are CommunicatedISO 8583 Reversal Transactions: How Failed and Timed-Out Payments Are RecoveredSTAN vs RRN in ISO 8583: What’s the Difference?ISO 8583 Field 3: Processing Code ExplainedISO 8583 Field 4: Transaction Amount and Minor UnitsISO 8583 Field 11: STAN Generation and Transaction TracingISO 8583 Field 22: POS Entry Mode ExplainedISO 8583 Field 35: Track 2 Data and PCI-Safe HandlingISO 8583 Field 37: Retrieval Reference Number ExplainedISO 8583 Field 41: Terminal Identification in Payment SystemsISO 8583 Field 42: Merchant Identification ExplainedISO 8583 Field 49: Currency Codes and Minor UnitsISO 8583 Field 52: PIN Data and Secure PIN ProcessingPayment Switch Architecture: How Financial Transactions Are Routed ReliablyCard Payment Transaction Flow: From POS Terminal to Issuer and BackIssuer vs Acquirer: Roles in Card Payment ProcessingHow Payment Gateways Work: Architecture, APIs, Security and ReliabilityPayment Reversal Flow: Recovering Timed-Out Financial TransactionsAuthorization, Clearing and Settlement ExplainedHardware Security Modules in Payment Systems: What Software Engineers Need to KnowIdempotency in Financial Transactions: Preventing Duplicate PaymentsPayment Reconciliation: Matching Transactions, Settlement and ExceptionsHigh-Availability Payment Systems: Reliability and Disaster RecoveryLaravel Production Architecture: Building Reliable APIs and Enterprise ApplicationsLaravel Sanctum Authentication for SPAs and APIsLaravel Socialite: OAuth Login ArchitectureLaravel Reverb and WebSockets in ProductionLaravel Queues in Production: Workers, Retries and Failed JobsLaravel with Docker in ProductionLaravel API Security: A Production ChecklistFlutter Application Architecture for Large Mobile and Desktop SystemsFlutter Offline-First Architecture: Local Data, Sync and ConflictsFlutter Windows Deployment: Builds, Installers and VersioningFlutter ERP Architecture for Connected and Offline Business SystemsFlutter Multi-Currency Accounting: Preserving Transaction CurrencyNext.js Production Architecture: SEO, APIs, Deployment and PerformanceNext.js SEO Guide: Metadata, Schema, Sitemaps and PerformanceNext.js and Laravel Architecture: Authentication, APIs and DeploymentNext.js with Docker in ProductionReact Application Architecture: Components, State, APIs and PerformanceDocker Production Guide: Images, Containers and Reliable DeploymentNginx Reverse Proxy: TLS, WebSockets, Headers and TimeoutsNginx and Certbot HTTPS: Certificate Lifecycle and Docker OperationsCI/CD Pipeline Design: Build, Test, Deploy and Roll Back SafelyGitHub Actions Guide: Workflows, Artifacts and Secure DeploymentJenkins CI/CD: Pipelines, Agents and Reliable DeploymentAWS EC2 Application Deployment: Docker, Nginx, TLS and OperationsMicroservices Architecture: Boundaries, Communication and Failure HandlingREST API Design: Resources, Validation and IdempotencyDatabase Design for Enterprise ApplicationsRedis in Production: Cache, Sessions, Queues and Failure HandlingSoftware Architecture Guide: Monoliths, Microservices and Trade-offs