How a Basic JS Calculator Can Evolve Into a Real-World Utility Tool

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A tutorial on DEV Community walks developers through transforming a standard JavaScript calculator exercise into a practical, real-world application. Using a UAE end-of-service gratuity calculator as a case study, the article demonstrates how production-ready tools must handle input validation, edge cases, and partial-period calculations. The piece includes a simplified JavaScript function that estimates gratuity based on salary and years of service, while noting that a full implementation would require date handling, unpaid-leave adjustments, and eligibility checks. Beyond arithmetic, the author emphasizes presenting a detailed result breakdown so users can verify inputs and understand how the final figure was reached. The article concludes that expanding a beginner project into a useful tool builds broader skills in product design, usability, and responsible information presentation.

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How to Build a Confidential OTC Settlement Protocol Using Oasis Sapphire and Base

A new developer tutorial on DEV Community walks through building a privacy-preserving over-the-counter trading protocol for large cryptocurrency transactions. The protocol combines confidential smart contract execution on Oasis Sapphire with transparent on-chain settlement on Base, an Ethereum Layer 2 network. It addresses a core challenge in decentralized finance: large trades executed through public liquidity pools expose sensitive order information to arbitrage bots and market participants, distorting prices. Oasis Sapphire enables confidential negotiation between counterparties directly within an EVM-compatible environment using standard Solidity code, keeping deal terms private until settlement. The tutorial covers key features including encrypted trade offers, private counterparty quotes, asset escrow, replay-attack prevention, and safe order cancellation.

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ProgrammingDEV Community ·

Why temperature=0 Does Not Make AI Agents Deterministic and How to Test Them

A technical article on DEV Community explains why AI agents can produce different outputs even when temperature is set to zero, a setting commonly assumed to eliminate randomness. The variation stems from floating-point arithmetic on GPUs, request batching by model providers, and infrastructure changes such as hardware swaps or model re-quantization. Tests that rely on exact string matching therefore fail intermittently even when the agent is functioning correctly, eroding developer trust in test results. The article recommends shifting assertions away from literal text matching toward verifying output structure, required fields, data types, and valid values. Using JSON Schema validators like Ajv is proposed as a practical approach to writing resilient, semantics-focused tests for non-deterministic AI systems.

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ProgrammingDEV Community ·

How Developers Can Build a Reusable Crypto Payment Kit for Agencies to Resell

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ProgrammingDEV Community ·

How a Misrouted S3 Worker Almost Handed a Startup a $30,000 AWS Bill

A startup came within 48 hours of receiving a $30,000 AWS invoice after a worker process fetched millions of small JSON files from S3 through a NAT gateway, which charges for every byte of data it routes. The NAT gateway, sitting between the company's private subnet and the internet, silently metered all traffic without any obvious warning to the engineering team. The fix required no application rewrite — adding a VPC gateway endpoint for S3 rerouted traffic through AWS's private network, eliminating the costly NAT charges entirely. The incident highlights a broader cloud cost trap: small-file workloads at scale generate disproportionate per-request overhead, and cross-AZ or NAT-routed traffic can quietly drain budgets. Engineers are advised to trace the physical path of data traffic before scaling any data-moving workload, since intra-region endpoint-routed traffic is often free while NAT-routed traffic is not.

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