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.
App Overview
MBOX Viewer
MBOX Viewer – Open MBOX Files
$4.99 · In-app purchases
PRICE
$4.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 5.0
1 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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What's included17 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.
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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Free quick prompt For a smaller starting point
Quick prompt
Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.
// RORK SYSTEM PROMPT
Rork plan preview for MBOX Viewer: 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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Continue in Rork >
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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
Expand to support various file formats and functionalities.
Assumption to check: Limited MBOX file handling capabilities.
Validate with people who use this workflow before building.
Hypothesis 2
Provide an onboarding process for new users.
Assumption to check: Lack of user guidance or tutorials.
Validate with people who use this workflow before building.
Hypothesis 3
Implement sharing features for ease of use.
Assumption to check: No sharing options for MBOX content.
Validate with people who use this workflow before building.
Hypothesis 4
Add a restore purchases option for user convenience.
Assumption to check: No restore purchases feature.
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
MBOX Viewer – Open MBOX Files Open, read, and export MBOX files on iPhone, iPad, and macOS. One Purchase. All Your Apple Devices. No subscription. No ads. No recurring fees. MBOX Viewer is a fast and private MBOX file viewer for Apple devices. Open .mbox email archives from Gmail Takeout, Thunderbird, and other email clients. Works completely offline with all data stored locally on your device. Features • Open and read MBOX (.mbox) email files • Gmail Takeout MBOX support • Thunderbird MBOX compatible • Large MBOX file support • Browse emails by sender, subject, and date • Search and read full email content • Export emails to PDF, HTML, or TXT • Share individual emails as EML • Offline MBOX viewer • One-time purchase — no subscription • No ads, no tracking Privacy First All email data stays on your device. No cloud upload. No accounts. No data collection. Supported Format • MBOX (.mbox) If you need a reliable MBOX viewer for Gmail Takeout or Thunderbird archives, MBOX Viewer makes opening and exporting MBOX files simple and private.
Written user reviews are not shown here. Check current App Store reviews >
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
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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.
