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
Day One
Apple’s App of the Year with over 15 million downloads and 200,000 5-star ratings globally, Day One has reinvented journaling letting you record your life as you live it
Free · In-app purchases
PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
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.
Generating… usually about a minute.
Make it yours Optional
What should your app do differently? Your note travels with the kit so your coding agent builds around your idea.
What's included18 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.
JavaScript is required to complete mailbox verification.
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 Day One: map the core Lifestyle 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 >
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 user experience by reducing options and providing guided onboarding.
Assumption to check: Users often feel overwhelmed by too many features.
Validate with people who use this workflow before building.
Hypothesis 2
Allow users to customize themes, fonts, and layouts.
Assumption to check: Lack of customization options for entries.
Validate with people who use this workflow before building.
Hypothesis 3
Implement better search and filtering options for journal entries.
Assumption to check: Difficulty in finding past entries.
Validate with people who use this workflow before building.
Hypothesis 4
Optimize the app for better performance on a wider range of devices.
Assumption to check: Inconsistent performance on older devices.
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
Apple’s App of the Year with over 15 million downloads and 200,000 5-star ratings globally, Day One has reinvented journaling letting you record your life as you live it. Securely save audio, video, photos, notes, and more in the world’s most trusted digital journal. “Day One creates something so rare it feels almost sacred: A completely private digital space.” – New York Times “Day One makes keeping a journal delightfully easy.” – Wired “This superb journaling app remains pleasant to behold, easy to use, and a tough act for any rival to follow.” – Macworld WHY DAY ONE? Day One is the original journal app and a decade of updates and feature additions make it the most private, trusted, and easiest-to-use journaling platform in the world. SIMPLE TO USE, EASY TO LOVE • Beautiful, award-winning design • Unlimited text entries • Unlimited photos and videos* • Powerful rich text formatting with markdown • Different journals for every aspect of your life* PRIVATE AND SECURE • Automatic backups keep your journal entries safe • End-to-end encryption, which is a fancy way of saying your entries are 100% private • Journal entries stay secure with passcode or TouchID • Export options (pdf, plain text, JSON, etc.) ensure your entries always stay yours FORM A HABIT & STAY CONSISTENT • Programmable reminder notifications • Unique, daily journal prompts help eliminate writer’s cramp • Customizable templates save time and add organization to entries • Today view provides a summary of where you’ve been and what you’ve done JOURNAL FROM WHEREVER, WHENEVER • Cross-platform apps available on iPhone, Apple Watch, iPad, and Mac • The ability to email entries straight to your journal BUILT FOR REMINISCING • On This Day feature allows you to revisit past memories • Tags, favorites, and search filters make it easy to find what you’re looking for • Map view quickly shows all the places you’ve journaled from *Day One is FREE to use forever with unlimited entries. Additional features, including unlimited photos, videos, and sync are available with a Day One Premium membership. Start a free trial today. Privacy Policy: https://dayoneapp.com/privacy-policy/ Terms of Use: https://dayoneapp.com/terms-of-use/ For technical assistance or other inquiries: https://dayoneapp.com/contact/
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
Redux
Firebase
React Navigation
TypeScript
BUILD KIT DIFFICULTY
Advanced
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.
