We are looking for a freelancer or development team to build a simple, practical mobile app for Unikem, a company specialized in drilling fluid additives for trenchless / HDD applications. The app will act as a field support tool, helping operators quickly determine: which products to use how much product is needed correct dosage and basic treatment recommendations The focus is speed, clarity, and accuracy in real job-site conditions. - Core Functionality (Main Goal) The app must include a calculator where the user inputs key project data: Bore diameter Bore length Soil type (predefined selectable categories) Water quality (basic classification) Estimated mud volume Drilling objective or problem (e.g. stabilization, lubrication, fluid loss, etc.) Based on these inputs, the app returns: Recommended product(s) Quantity required Dosage range Simple usage instructions The logic will be rule-based and formula-driven, and will be fully provided by us. - Features & Requirements Clean, simple UI optimized for field use (fast input, clear output) Ability to recommend multiple products in combination Output screen must clearly display: product name dosage quantity short notes/instructions Product screen should include: product image Technical Data Sheet (PDF) Share/export function (for sending or saving calculation summaries) App must work offline after initial data download (calculator + documents) Architecture must allow: easy update of products and formulas future addition of languages English language initially (multi-language ready) - Technical Preferences Mobile app (iOS + Android) preferred Single codebase preferred (Flutter / React Native), but open to alternatives Performance and maintainability are more important than specific framework - Deliverables Full source code Build and deployment instructions TestFlight (iOS) and internal testing build (Android) Proper structure for future updates - We Will Provide Product list Technical data sheets Calculation formulas and selection logic Example calculation sheets (if needed) - Nice to Have Experience with technical / industrial / engineering calculators Experience with offline-first apps Ability to design simple, intuitive UX - To Apply, Please Include Examples of similar apps or calculators you have built Your proposed tech stack Estimated timeline to MVP Estimated budget Any suggestions to improve reliability and usability - Budget Open to proposals