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
Letterboard SpellerBuddy
Letterboard SpellerBuddy is the ultimate typing assistant designed specifically for spellers who use letter boards
$9.99 · In-app purchases
PRICE
$9.99
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.
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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 should your app do differently? Your note travels with the kit so your coding agent builds around your idea.
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 Letterboard SpellerBuddy: map the core Education 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
Incorporate gamification elements like badges and leaderboards.
Assumption to check: Limited engagement for users
Validate with people who use this workflow before building.
Hypothesis 2
Enable offline downloads for lessons.
Assumption to check: Lack of offline access
Validate with people who use this workflow before building.
Hypothesis 3
Add a detailed progress dashboard with visual stats.
Assumption to check: Inadequate progress tracking
Validate with people who use this workflow before building.
Hypothesis 4
Implement tailored lesson plans based on user performance.
Assumption to check: No personalized learning paths
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
Letterboard SpellerBuddy is the ultimate typing assistant designed specifically for spellers who use letter boards. Whether your child is just learning the alphabet or advancing to QWERTY, this app grows with them. Key Features: • Multiple Keyboard Layouts - Choose from ABC alphabetical, QWERTY, Grid, or full-screen Letterboard modes • Customizable Experience - Adjust key sizes, text colors, and spacing to match your child's needs. Extra-large text options available for users with vision challenges • Smart Word Suggestions - Kid-friendly vocabulary with context-aware predictions to build confidence • Text-to-Speech - Hear letters and words spoken aloud with adjustable voice speed • Built-in Calculator - Scientific calculator with graphing capabilities for math practice • Metronome - Real clock sounds from 10-120 BPM to help with rhythm and pacing • Cloud Save - Google Drive integration to save and sync progress • Bluetooth Support - Use external keyboards with the Letterboard mode Designed with accessibility in mind, Letterboard SpellerBuddy supports learners of all abilities.
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
React Native
Expo
Zustand
React Navigation
expo-av
BUILD KIT DIFFICULTY
Starter
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.
