App Overview

Number Shield icon

Number Shield

Kinnaman Software LLC · Utilities

Block annoying scammers who hide behind fake phone numbers.

$2.99 · In-app purchases

PRICE
$2.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
4.5
1,879 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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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.

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.

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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> SELECT BUILD PLATFORM:

Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.

// RORK SYSTEM PROMPT
Rork plan preview for Number Shield: 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 customize number formats and types more extensively.

Assumption to check: Limited number of customizations for generated numbers

Validate with people who use this workflow before building.

Hypothesis 2

Integrate a help center or chat support within the app.

Assumption to check: Lack of user support options

Validate with people who use this workflow before building.

Hypothesis 3

Implement a more gradual introduction to premium features.

Assumption to check: Paywall after few uses can frustrate users

Validate with people who use this workflow before building.

Hypothesis 4

Add iCloud sync to save user-generated numbers across devices.

Assumption to check: No backup or sync options

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

Block annoying scammers who hide behind fake phone numbers. Do you get unwanted calls or text messages from phone numbers similar to your own? With Number Shield, block an entire group of numbers at once. Just enter a wildcard for each digit you want to block. For example, if your number is 714-555-1234, scammers might use a number like 714-555-6789. Block all similar numbers by entering 714-555-####. Wildcards and numbers can be combined in any order you choose. Block international numbers, too! To make sure you don't miss calls from your family and friends, phone numbers in your contacts are always allowed. Block numbers directly from your phone's missed calls screen. Just follow these steps: 1. Tap the “ i ” button next to the missed call. 2. Tap “Share Contact”. 3. Tap “Block Similar Numbers”. (If you don't see this action, tap “Edit Actions...“ to enable it.) 4. Now you'll see the Number Shield number entry screen. Tap “Done” to block calls from similar numbers. Please note: • Each number pattern can contain up to 7 wildcards, and up to 50,000,000 phone numbers can be blocked. • Blocked calls are sent directly to voice mail. • Blocked text messages are sent to the “Junk” filter in the Messages app. • iMessage messages are not blocked. • When “Do Not Disturb” is enabled on your phone, calls that should be blocked may appear in your phone's list of missed calls. More information about caller ID spoofing in the United States is available from the FCC: https://www.fcc.gov/spoofing

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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
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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.