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
Python Challenge
Feed your brain
$3.99 · In-app purchases
PRICE
$3.99
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's included15 files
A product spec, phased build plan, differentiation notes, and screen references.
- START_HERE
- AGENTS
- EVIDENCE
- SPEC
- BUILD_PLAN
- DIFFERENTIATION
- skills/
- screens/
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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 Python Challenge: map the core Developer Tools 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 a personalized recommendation system based on user progress and preferences.
Assumption to check: Users often feel overwhelmed by the number of challenges.
Validate with people who use this workflow before building.
Hypothesis 2
Introduce gamification elements like badges and rewards for completed challenges.
Assumption to check: Challenges may lack variety and engagement.
Validate with people who use this workflow before building.
Hypothesis 3
Provide clearer descriptions and examples for each difficulty level.
Assumption to check: Difficulty levels may not be well-defined.
Validate with people who use this workflow before building.
Hypothesis 4
Create a more visual and interactive progress tracker with charts and stats.
Assumption to check: Users may find it hard to track their progress.
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
Feed your brain. Grow the snake. Learn algorithms by writing real Python — on your phone. Python Challenge is a single path of original coding challenges, from your first `return a + b` to N-Queens, edit distance and Dijkstra. Every solution runs on-device in real Python and is checked against hidden tests, so passing means it actually works. WRITE REAL CODE • A coder keyboard built for Python: tab, snippets, brackets, quotes, undo • Instant feedback with named tests, expected vs actual output • Some levels enforce rules (no sorted(), recursion required) so you learn the technique, not the shortcut LEARN THE RIGHT WAY • Three-tier hints from PySnake, your slightly sardonic mentor • Curated solutions after you solve: naive vs optimal, time and space complexity • Topics: strings, lists, sorting, searching, recursion, dynamic programming, data structures, graphs, heaps, bit tricks, grids, greedy, intervals, math STAY MOTIVATED • One path, no shortcuts: easy → medium → hard, with performance tests on the hard ones • XP, levels, daily streaks and ten badges • Six themes, dark and light PRIVATE BY DESIGN • Works fully offline, no account, no ads, no tracking — your progress stays on your device
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
Supabase
Zustand
React Navigation
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.
