App Overview

OnPhone: Second Number & eSIM icon

OnPhone: Second Number & eSIM

AnyDay Apps · Business

OnPhone lets you manage multiple phone lines for personal and business needs — all without an extra SIM card

Free · In-app purchases

PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
No overall Grossing estimate available
RATING
4.6
51,816 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 included18 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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Free quick prompt For a smaller starting point

Quick prompt

> SELECT BUILD PLATFORM:

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

// RORK SYSTEM PROMPT
Rork plan preview for OnPhone: Second Number & eSIM: map the core Business 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 choose area codes or number types.

Assumption to check: Limited customization options for second numbers

Validate with people who use this workflow before building.

Hypothesis 2

Offer more flexible pricing tiers or a pay-per-use model.

Assumption to check: High subscription costs for premium features

Validate with people who use this workflow before building.

Hypothesis 3

Simplify UI for better navigation and usability.

Assumption to check: Complex user interface for managing messages and contacts

Validate with people who use this workflow before building.

Hypothesis 4

Improve backend infrastructure for better call quality.

Assumption to check: Inconsistent performance and reliability on calls

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

OnPhone lets you manage multiple phone lines for personal and business needs — all without an extra SIM card. Instantly get a new phone number, make calls, and send texts worldwide while keeping your real number private. All phone numbers are fully compatible with social platforms and services such as WhatsApp, Telegram, iMessage, and many others. Choose from local phone numbers in the United States (US), United Kingdom (UK), France (FR), Brazil (BR), Canada (CA), Spain (ES), Mexico (MX), Australia (AU), South Korea (KR), Japan (JP), Hong Kong (HK) — and over 100 more countries! No need to swap SIM cards or carry extra devices — call and text from different numbers easily, anywhere you are. Affordable business and private calls, from anywhere to anywhere. Main Features * Voicemail: Let callers know why you can’t answer. Set custom Business Hours and redirect calls outside this period straight to voicemail. * Call Recording: Record both incoming and outgoing calls for reference or security. * Call Forwarding: Protect your privacy by forwarding calls to another number. * Spam Blocking: Stop unwanted calls instantly. * Send to Future: Schedule text messages to be sent automatically at any date and time. eSIM Data Plans Save up to 10x on mobile roaming fees with our built-in eSIM technology. Why eSIM is better: * Save money with fair, transparent data rates. * Stay connected across all your devices — no lost traffic when switching phones. * Manage unlimited eSIM profiles easily within your account. * Install in just a few taps — no physical SIM required. Send & Receive Faxes on the Go Fax directly from your iPhone or iPad — no fax machine or office needed! Key Fax Features: * Send faxes to 90+ countries worldwide. * Advanced document scanner & image processing for perfect quality. * Combine multiple documents into one fax and preview before sending. * Receive faxes from anywhere using your dedicated fax number. * Send almost any file type (PDF, DOC, JPG, PNG, TIFF, HTML). * Import documents from Google Drive, Files, or take photos on the go. Discover the best AI tools for calling and texting with OnPhone — smart solutions that make your communication faster, clearer, and more personal. From real-time voice assistants to intelligent text automation, OnPhone helps you stay connected effortlessly and efficiently. Premium Access Unlock all features with OnPhone Premium — your complete communication toolkit. Premium includes: * 1 Free Phone Number * Renewable Coins Package * Call Forwarding, Call Recording, Voicemail & Video Calls * eSIM Data Plans * Fax Sending & Receiving * App Protection with PIN & Touch ID Subscription Options * Weekly Plan (3-day free trial): $5.99 * Monthly Plan: $13.99 or $19.99 * 3-Month Plan: $39.99 * Annual Plan: $99.99 Prices may vary by location. Your iTunes account will be charged upon purchase confirmation and for each renewal. Free trials automatically convert to paid subscriptions unless canceled at least 24 hours before renewal. Manage or cancel anytime in your iTunes settings. Unused trial time will be forfeited once you upgrade to a paid plan. Privacy Policy: https://onphone.app/privacy.html
 Terms of Use: https://onphone.app/terms.html

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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
React Native
Expo
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Zustand
React Navigation
Axios
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.