App Overview

Seikyu: Invoice & Quote Maker icon

Seikyu: Invoice & Quote Maker

Yoshiaki Hirokawa · Business

Make a clean, professional invoice in one minute — no account, no subscription, no cloud.

$1.99 · In-app purchases

PRICE
$1.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
N/A
No ratings yet

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.

Build your own version

Build Kit

Make this idea yours

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

First kit free with a verified email

Add to a Remix

Combine features and design from your favorite apps.

Kit ready. Verify your email to download it.

What's included16 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.

JavaScript is required to complete mailbox verification.

Free quick prompt For a smaller starting point

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 Seikyu: Invoice & Quote 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.
            

Preview ready. Verify your email to reveal and copy the full prompt.

JavaScript is required to complete mailbox verification. Return to this prompt preview.

Continue in Rork copies the full prompt to your clipboard first, then opens Rork in a new tab.

Continue in Rork >

Affiliate link: CloneChart may earn a commission at no extra cost

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

Simplify the invoice creation process with templates.

Assumption to check: Users often struggle with complicated invoice formats.

Validate with people who use this workflow before building.

Hypothesis 2

Add integrations with popular accounting tools.

Assumption to check: Lack of integrations with accounting software.

Validate with people who use this workflow before building.

Hypothesis 3

Implement better tracking and notifications for payments.

Assumption to check: Difficulty in tracking payment statuses.

Validate with people who use this workflow before building.

Hypothesis 4

Offer more design customization options for invoices.

Assumption to check: Limited customization options for invoices.

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

Make a clean, professional invoice in one minute — no account, no subscription, no cloud. Invoice Maker is the invoicing app the way it should be: you buy it once, it works forever, and your business data never leaves your phone. Create quotes, invoices and receipts, share them as beautiful PDFs, and get back to work. WHY PEOPLE SWITCH TO INVOICE MAKER - One-time purchase — no monthly fees, ever - Completely offline — works on a plane, at a job site, anywhere - No signup, no tracking, no data collection. Your clients stay yours CREATE IN SECONDS - Quotes, invoices and receipts with automatic numbering - Reusable clients and items — tap to add - Quantity, unit price, per-line tax rates and automatic totals - Discounts, notes and payment details BUILT FOR YOUR COUNTRY - Your currency, your number format — automatically from your device - Freely configurable tax rates (VAT, GST, sales tax…) - Japan mode: fully compatible with the qualified invoice system (インボイス制度) — registration number and per-rate tax breakdown SHARE AS PDF - Crisp, professional PDF layouts - Send by email, message or any app straight from the share sheet - Mark documents as sent or paid, and track what's outstanding Note: in countries where structured e-invoicing is mandatory for B2B (e.g. CFDI, NF-e, FatturaPA), use Invoice Maker for quotes, receipts and records. Your invoices, your data, your phone. That's it.

Written user reviews are not shown here. Check current App Store reviews >

Screenshots

< Scroll to see more >

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
React Navigation
Axios
Async Storage
Shadcn/UI
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.