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
RANDOM.ORG
All randomness wasn't created equal
Free · In-app purchases
PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
No overall Grossing estimate available
RATING
★ 4.6
1,282 ratings · Top 15%
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 included16 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 RANDOM.ORG: map the core Utilities 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
Allow users to save templates for future use and customize settings.
Assumption to check: Limited customization options for generated numbers and sequences.
Validate with people who use this workflow before building.
Hypothesis 2
Add a share button to easily share results via social media or messaging apps.
Assumption to check: No option to share generated results directly.
Validate with people who use this workflow before building.
Hypothesis 3
Enhance UI with themes and additional features like history tracking.
Assumption to check: Some users find the interface too simplistic.
Validate with people who use this workflow before building.
Hypothesis 4
Introduce features that provide insights into generated numbers, like frequency and distribution.
Assumption to check: Lack of advanced features like statistical analysis.
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
All randomness wasn't created equal. This app offers certified true randomness, generated with atmospheric noise and independently approved by several testing labs. (See sample certificate from eCOGRA.) You can use our randomizers for free and without ads in this official app. If you would like to support our free services, you can do so by making a donation through our website: https://www.random.org/donate - Coin Flipper with 100 different coins from Ancient Rome to 27 modern currencies - Dice Roller to roll up to six regular dice in one go - Card Shuffler to shuffle playing cards and draw them one at a time - Lotto Quick Pick with more than 170 lotteries from all around the world - Integer Generator to generate true random numbers in configurable intervals - List Randomizer to create and randomize your own lists of items RANDOM.ORG was founded in 1998 and generates certified true randomness from atmospheric noise, which for many purposes is better than the pseudo-random numbers typically used in computer programs. Our mission is the generate the highest quality true randomness and make it available to the world in useful forms.
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
Async Storage
React Navigation
TypeScript
ShadCN/UI
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.
