Opportunities › File synchronization across isolated devices › Proposed app
Carryover
Two-way file sync for air-gapped computers using a plain USB drive
- Score
- 28
- confidence 39
- Evidence
- 2
- items on the page
- Rivals
- 0
- named in sources
- First version
- 30 d
- estimate
- Type
- Desktop app
- PWA: runs in the browser, installs on Mac and Windows
- Market since
- 2001
- Mature market · AI estimate
ScreensConcept
Desktop app: Technical users manage file syncs across air-gapped machines, preview changes carefully, and review detailed logs before committing changes, all desktop activities. Sample screens on a computer, in the proposed brand. Their numbers are sample data.
Lab-PC-2 ↔ Stick
Ready to sync14 changes
About this appAI proposal
Carryover keeps folders in step across computers that can never reach each other or a server. You carry one ordinary USB drive between them. On each machine you open Carryover, point it at a local folder and the drive, and it merges both ways.
It is for researchers, developers and teams with air-gapped or isolated systems who now copy files by hand. Carryover compares timestamps, keeps both versions when the same file changed on two machines, and writes a log you can check.
It runs as an installed web app that works offline, in a browser that can open folders. There is no hardware to buy and no account needed on the isolated machine.
- Tagline
- Keep isolated machines in step with one USB stick.
- Voice
- PlainPreciseCalm
- Why this name
- Carryover describes the act: files are carried from one machine to the next on a stick and left in step. It is two plain words joined, easy to say.
In the first version
Members say which features they would use. It tells PWAS what people want; it changes no score.
Two-way folder merge
Pick a local folder and a USB drive. Carryover copies new and changed files in both directions in one pass.
No member yet
Timestamp conflict rules
Newest modified time wins by default. Choose keep-both, which renames the older copy, or ask each time.
No member yet
Many machines, one stick
The drive holds a shared bundle. Each machine that visits picks up what the others left.
No member yet
Preview before writing
See every file to add, replace or rename before anything is changed. Nothing is deleted without approval.
No member yet
Brand identityAI proposal
Check the name against trademark registers before using it.
Palette
#0F5C54Deep Teal · primary#F6F3EAPaper · surface#1B2B2AInk · text#E0873AAmber · accent#3C6E9ESlate Blue · data
Typography
Aa
Carryover
ABCDEFGHIJKLMNOPQRSTUVWXYZ 0123456789
Keep isolated machines in step with one USB stick.
PricingAI proposal
The material gives no competitor prices. One public claim says people would pay about $100 for a hardware device. These software tiers are a starting point to test against that figure.
Free
Free
- One folder pair
- Up to 2 machines
- Timestamp rules
- Basic log
Pro
$60 a year
- Unlimited folders
- Unlimited machines
- Preview and keep-both rules
- Checksummed report export
Team
$240 a year
- Up to 15 users
- Shared rule presets
- Audit report templates
- Priority support
Would you pay Pro · $60 a year?
Your answer tells PWAS which prices people accept. It changes no score.
No answers yet.
What it could be worthEstimate
What a software business making this much sells for today, from real deals. Pick a monthly revenue.
If it makes
Worth about
$194,000
Sale range $132,000 to $263,000
$120,000 a year in revenue
From 87 software businesses listed and sold on Empire Flippers in the last year, revenue vetted by the broker: they sell for about 19× their monthly revenue, most between 13× and 26×.
Measured on profit, the middle deal is 32× monthly net profit: about 2.7 years of profit.
An estimate, not an offer or financial advice. A real price depends on profit, growth, churn, how much of the work is the owner's, and the buyer.
How it would growAI proposal
How the product would reach new customers through its own use, and how the first ones would be found. A plan to test, not a result.
- Built-in loop
- Shared outputs. Each sync can export a plain-text or HTML transfer report that a security reviewer or collaborator opens. The report carries the Carryover name and a link to how it works.
- Do they become customers?
- Recipients of a report are existing colleagues, often on the same isolated machines, so some may become buyers. Whether a report reader installs the tool and pays is untested.
- First customers
- Small research labs and engineering teams, 5 to 30 people, that move files by USB between instrument or air-gapped computers.
- Where to reach them
- Hacker News and Show HN: Post a demo for the sneakernet sync problem and reply to people who describe isolated-device setups.
- Research computing forums: Offer it to lab and instrument-computer admins who move data by USB today, with a short how-to.
- Security and ICS communities: Write a guide on auditable removable-media transfers and invite admins to try the log export.
- First milestone
- Ten teams use it weekly for a month and five pay for Pro, showing that software on a normal USB drive meets the need.
Why people already pay for this
- Public claimUsers would pay around $100 for a physical device that synchronizes files across multiple isolated devices through USB emulation.
- Public claimThe sync device would need to handle conflict resolution based on file timestamps when the same file exists on multiple devices.
Tech stack
Every proposal builds on the same PWA base, installable from the browser on any phone or computer. Dashed boxes are what this app adds.
- AppNext.js and TypeScript
- PWAManifest and service worker
- UITailwind CSS
- Data and authSupabase Postgres
- PaymentsStripe
- EmailResend
- HostingVercel
- This app · Local folder accessBrowser File System Access APIReads and writes the chosen folder and the USB drive with no server.
- This app · Offline storageIndexedDB with hashing in a web workerKeeps per-machine sync state and file hashes without a network.
RisksAI inference
- PlatformFolder access in the browser depends on the File System Access API, which is not in every browser. Locked-down machines may only have browsers without it.
- CommercialThe source idea is a $100 hardware device that needs no software on each machine. Many isolated machines forbid installing anything, so this may not fit them.
- TechnicalInstalling the app on a machine with no internet needs an offline route, such as copying it from the drive. Browsers may limit that for service workers.
- TechnicalTimestamps can differ because of clock drift or file systems like FAT, so the wrong version may win. Keep-both and preview are needed to limit data loss.
- RegulatorySecure environments may need approval of any software that touches removable media. That slows sales and may need open source or review of the code.
Everything marked AI proposal or AI inference was written by a model from the evidence on the opportunity page. The proposed name must be checked against trademark registers before it is used.