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.
Letterloop is a fun way to have a group newsletter without the work
Free · In-app purchases
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.
A product spec, screen plans, and build steps for your coding agent.
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Combine features and design from your favorite apps.
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What should your app do differently? Your note travels with the kit so your coding agent builds around your idea.
A product spec, phased build plan, differentiation notes, and screen references.
Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.
Goal: Send a clear invoice after finishing a job.
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.
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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Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.
Rork plan preview for Letterloop: Group Newsletters: map the core Books workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
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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
Assumption to check: Limited newsletter customization options
Validate with people who use this workflow before building.
Hypothesis 2
Assumption to check: Difficulties in managing subscriptions
Validate with people who use this workflow before building.
Hypothesis 3
Assumption to check: Lack of community engagement features
Validate with people who use this workflow before building.
Hypothesis 4
Assumption to check: Inconsistent content discovery
Validate with people who use this workflow before building.
Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.
Letterloop is a fun way to have a group newsletter without the work. You pick the questions for your group to answer, then Letterloop creates a fun and beautiful newsletter with everyone's replies. All you need is to do is invite your people! How does Letterloop work? We crafted a set of questions designed to spark fun and thoughtful replies. The questions range from updates about your week to thoughts on identity, life stories, and personal philosophies. Each newsletter cycle, we'll suggest a few questions for you. You can always swap questions or add your own. Plus, members of your newsletter can ask their own questions that you can include too. Who uses Letterloop? Groups of all kinds use Letterloop to grow close together, even when far apart. - Families - Friends - Teams - Universities - Clubs & Masterminds - Youth Groups - Communities Why Letterloop? - Stay in touch, grow closer together, and discover things you never knew with the people in your life - Let everyone ask and answer fun & interesting questions that don't normally come up in group chats or video calls - Customize your Letterloop's content, schedule, and settings to match your group's interests and personalities - Reschedule, pause, or extend a Letterloop issue as needed - Access unlimited archives of your Letterloop's historical issues - You're always in full control of your Letterloop data — no ads, ever Letterloop Subscription - You may purchase an auto-renewing subscription through an In-App Purchase. - Subscriptions include Letterloop Monthly ($5.00/month) and Letterloop Annual ($50.00/year) - Your subscription will be charged to your iTunes account at confirmation of purchase and will automatically renew (at the duration selected) unless auto-renew is turned off at least 24 hours before the end of the current period. - Current subscription may not be cancelled during the active subscription period; however, you can manage your subscription and/or turn off auto-renewal by visiting your iTunes Account Settings after purchase Privacy Policy: https://www.letterloop.co/privacy-policy Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Written user reviews are not shown here. Check current App Store reviews >
Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.
Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.
Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.
Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.
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.