App Overview

Base64 Encode Decode Offline icon

Base64 Encode Decode Offline

LEAN ASIA CO., LTD · Developer Tools

Paste a Base64 string, tap once, read the answer — right on your iPhone, fully offline

Free

PRICE
Free
No in-app purchases
BUSINESS MODEL
Free
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.

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Build Kit

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A product spec, screen plans, and build steps for your coding agent.

First kit free with a verified email

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What's included

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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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 Base64 Encode Decode Offline: map the core Developer Tools 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

Add features like batch encoding/decoding and history tracking.

Assumption to check: Limited functionality for advanced users

Validate with people who use this workflow before building.

Hypothesis 2

Implement a modern UI design with better visuals.

Assumption to check: User interface may feel outdated

Validate with people who use this workflow before building.

Hypothesis 3

Integrate sharing functionality to easily share results via social media or messaging.

Assumption to check: No sharing options for encoded/decoded strings

Validate with people who use this workflow before building.

Hypothesis 4

Optimize performance for handling larger text inputs without lag.

Assumption to check: Lack of support for large texts

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

Paste a Base64 string, tap once, read the answer — right on your iPhone, fully offline. No web converter, no upload, no wondering who just logged the token you pasted. Base64 Encode Decode Offline is a developer scratchpad built for the real thing you paste: blobs copied out of logs and terminals. The decoder tolerates URL-safe alphabets, missing padding and line-wrapped copy-paste, auto-detects whether you meant encode or decode, and refuses garbage instead of returning silent nonsense. URL decoding is byte-accurate, so a leading BOM or odd byte is preserved instead of being quietly eaten. Everything renders in a proper monospaced font. WHAT YOU GET • A wrapped, unpadded, URL-safe Base64 blob from a log file still decodes cleanly — whitespace, CRLF and base64url handled for you • Paste a JWT and read its pretty-printed header and payload immediately — the signature never touches a server • One input, four digests: MD5, SHA-1, SHA-256 and SHA-512 update as you type, with one button to copy all four • URL-encode a query value and the &, =, + and # characters that break query strings are actually escaped • Turn any file into Base64 or a ready-to-embed data URI with the correct MIME type — and turn Base64 back into a file • The String Inspector shows characters, UTF-8 / UTF-16 / UTF-32 byte counts, words and lines the moment text is entered PERFECT FOR • Backend and mobile developers debugging an API payload away from the laptop • QA engineers inspecting auth tokens without pasting credentials into a website • Sysadmins decoding config blobs and verifying checksums from a phone session • Students seeing exactly how encodings and hash digests behave WHY NOT JUST USE A WEB CONVERTER? Because every online encode/decode tool receives your string on its server — and the strings developers convert are exactly the ones that should never leave the machine: session tokens, API keys, connection strings, JWTs. This app does all conversion and hashing on the device with Apple's CryptoKit. It works in airplane mode. PRIVATE BY DEFAULT No accounts, no tracking of your content, no network needed to convert. Your inputs and your conversion history are stored only on your iPhone. FULL ACCESS Pro unlocks unlimited saved conversions, file conversion beyond 5 MB in both directions, and Batch mode to convert many lines in one pass. Full access is available as a weekly subscription, a yearly subscription, or a one-time lifetime purchase. Decode that string before the next station — download Base64 Encode Decode Offline. Terms of Use: https://leanstudio.asia/terms-of-use Privacy Policy: https://leanstudio.asia/privacy-policy Support: [email protected]

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
React Navigation
React Native Elements
expo-clipboard
BUILD KIT DIFFICULTY

Not assessed in a Build Kit yet.

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.