App Overview

Billdu: Invoice Estimate Maker icon

Billdu: Invoice Estimate Maker

BILLDU LTD · Business

Billdu is your all-in-one invoice maker, estimate generator, and billing app designed for small businesses, contractors, and freelancers in the US

Free · In-app purchases

PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
No overall Grossing estimate available
RATING
4.8
26,087 ratings · Top 5%

Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.

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Build Kit

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A product spec, screen plans, and build steps for your coding agent.

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Combine features and design from your favorite apps.

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What's included18 files

A product spec, phased build plan, differentiation notes, and screen references.

  • START_HERE
  • AGENTS
  • EVIDENCE
  • SPEC
  • BUILD_PLAN
  • DIFFERENTIATION
  • skills/
  • screens/
Preview a sample Build Kit No email needed

Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.

Feature spec

Goal: Send a clear invoice after finishing a job.

  • Add a client, line items, a due date, and payment instructions.
  • Preview the total before exporting a PDF.
  • Keep an editable draft if export fails.

Screen plan

Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.

States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.

Differentiate and validate

Hypothesis: Contractors need faster repeat invoices more than more templates.

First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.

The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.

Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.

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Quick prompt

> SELECT BUILD PLATFORM:

Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.

// RORK SYSTEM PROMPT
Rork plan preview for Billdu: Invoice Estimate Maker: map the core Business workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
            

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Opportunities

AI-GENERATED OPPORTUNITY HYPOTHESES

These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.

Hypothesis 1

Implement better filtering and sorting options.

Assumption to check: Difficulties in managing multiple invoices efficiently

Validate with people who use this workflow before building.

Hypothesis 2

Provide more templates and design customization.

Assumption to check: Limited customization options for invoices

Validate with people who use this workflow before building.

Hypothesis 3

Create a more intuitive navigation structure.

Assumption to check: Confusing navigation between different features

Validate with people who use this workflow before building.

Hypothesis 4

Optimize the app's performance for a smoother experience.

Assumption to check: Inconsistent performance on lower-end devices

Validate with people who use this workflow before building.

App evidence

Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.

App Store description

Billdu is your all-in-one invoice maker, estimate generator, and billing app designed for small businesses, contractors, and freelancers in the US. Whether you’re creating a simple invoice, a professional estimate, or tracking receipts, Billdu makes it fast, easy, and reliable. Why choose Billdu? • Customizable Invoice Templates – Personalize with your logo, colors, and signature. Choose from professional layouts that impress clients. • Instant Estimates & Invoices – Create and send documents right after the job is done. • Get Paid Faster – Enable Stripe-powered Online Payments to accept credit cards, Apple Pay, Google Pay, and other popular payment methods. • Expense Tracking – Scan receipts, categorize expenses, and keep your business finances organized. • Contractor-Friendly Tools – Perfect for construction, plumbing, electrical, and service-based businesses. • Multi-Device Sync – Access your account and data from iPhone, iPad, or desktop in real-time. • Inventory Management – Track products, manage stock, and add items to invoices in one tap. • Client Management – Store and organize client data, import from contacts, and send reminders. Who Billdu is for? Billdu is perfect for contractors, estimators, and service companies including: painters, concrete, HVAC, roofers, renovators, plumbers, siding, lawn care, construction, electricians, carpenters, flooring, builders, pest control, tile, handymen, landscapers, drywallers, paving, remodeling, arborists, cleaning, general contractors, scaffolding, insulation, pool, EV charger installers and more! Advanced Features: - Attach product images to invoices - Know when an invoice was opened - Connect directly with your accountant - Use offline and sync later - Secure with Face ID or Touch ID - Generate reports and track cash flow Flexible Plans: Try Billdu free for 7 days. Upgrade to Lite, Standard, or Premium for unlimited invoices, estimates, and clients. Billdu helps you save time, get paid faster, and stay organized — all while maintaining a professional image. Terms: https://my.billdu.com/page/condition Privacy: https://my.billdu.com/page/protection

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Screenshots

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Build scope

Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.

Define the first version

Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.

Set boundaries

Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.

Check the hard parts

Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.

SUGGESTED BUILD STACK
React Native
Expo
Supabase
zustand
react-query
expo-router
BUILD KIT DIFFICULTY
Intermediate

From the Build Kit assessment.

A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.