LanFuture01 / Understand
Diagnostics with a location
Run bounded built-in checks and pinned official EPUBCheck 5.3.0 locally, with bundled Java. Inspect severity, origin and resource paths in a focused review workflow.
EPUB production / Book Preflight Studio
Understand EPUB errors.
Keep your original.
You already have an EPUB. Understand its structural diagnostics, approve a few narrow container repairs, and export a revalidated copy while keeping your original.
Planned $39 USD / v1 · Local checks without an API key
A specific job, not an everything app
Independent authors, small publishers and production freelancers with a supported EPUB ready for structural review.
Your authoring tool remains the editor. This is the review and handoff desk beside it.
02 / Approve
Small repairs. Explicit consent.
Only three existing mimetype-marker repairs are automated: ZIP position, uncompressed/no-extra-field storage and proven padding/BOM normalization. Content edits stay manual.
03 / Revalidate
A separate copy, with evidence
Recheck original and proposed snapshots before export. Compare resource payload hashes and refuse newly introduced findings under those checks. Existing unrelated issues can remain.
Try first. Understand the difference.
A useful preview.
A fuller desktop workflow.
One recorded synthetic report. Browse actual EPUBCheck and built-in diagnostics. No file import, live EPUBCheck, repair or export is run on this page.
| Workflow | Free browser preview | Planned desktop v1 · $39 |
|---|---|---|
| Input | One recorded synthetic report | Your supported unencrypted EPUB 2/3; up to 50 MiB / 2,000 entries |
| Diagnostics | Browse previously generated findings | Run bounded checks and bundled EPUBCheck locally |
| Repair & handoff | No repair, validation or export is run | Three consented mimetype repairs; before/after revalidation, reports and backups |
Inspect the actual output
Real format.
Synthetic content.
The sample EPUB and report are synthetic. The report includes actual local EPUBCheck diagnostics. An example is not a promise of store approval or complete repair.
Example data/report files, not installers, paid licenses or customer work.
Know the boundaries
Useful by design.
Specific in scope.
Supported scope
Supported unencrypted UTF-8 EPUB 2/3 only: 50 MiB input, 2,000 entries, 100 MiB expanded, 10 MiB/resource and 2 MiB/XML. No DRM/font obfuscation, signatures, ZIP64, DTD, multiple renditions or remote manifest resources. Valid EPUBs outside this bounded profile may be refused. Not a converter, PDF tool, editor, layout preview or universal repair service.
Optional AI, separate costs
Optional cloud explanations use your own OpenAI API account. Only selected, previewed diagnostics and their path/context are sent, not an attached manuscript. Diagnostics can contain sensitive excerpts. API charges are separate. AI never edits the book or certifies accessibility.
Planned v1 launch price
$39 USD / one time
One person, one transferable device. A 14-day evaluation is built into the apps; public installer delivery is not open yet.
Sales are not open yet.
Final license/refund/support terms, release platforms and automatic delivery must be verified before checkout opens. API usage, future major versions and lifetime support are not included in this planned price.
Try the free browser previewAsk about availabilityBefore you decide
A few useful answers.
Why not use free EPUBCheck?
You can. EPUBCheck and Ace remain independently available tools. This application's proposed value is its guided local project, decisions, narrow repairs, revalidation and handoff workflow, not proprietary validation rules or proven superiority.
Will it fix every EPUB problem?
No. Only the three declared mimetype-container repairs are automated. Text, layout, content, links and other structural issues may need an editor and manual review.
Does it certify accessibility or KDP acceptance?
No. Ace is not run by the app. Imported Ace JSON remains external evidence. Store acceptance, visual rendering and accessibility require separate evaluation.
What does the trial do after 14 days?
New analyses require a v1 license. Existing projects remain readable, with report export and backup available. Public installer delivery is not open yet.
Availability
Explore today.
Purchase after release.
The free previews and sample reports are available now. Desktop applications are functional local candidates; paid delivery is not open while the commercial handoff is verified.
- Linux x64
- Exercised locally on Fedora. Other distributions and clean-machine coverage are not implied.
- Windows x64
- Unsigned installers generated. Windows installation, upgrade, removal and signing decision remain pending. No macOS release.
- Purchases
- Merchant identity/receiving funds, final terms and end-to-end download/licensing verification are pending. There is no active purchase button.
- Optional AI
- Bring your own API account; provider charges are separate. Paid production inference and linguistic gains have not been independently verified. Core local features do not require an API key.
Technical privacy overview
Your work stays local.
AI is a separate choice.
The desktop apps store snapshots, projects and review history locally. Core checks do not require cloud AI. License activation/validation contacts the licensing service when used. Optional AI sends the exact request you preview and approve; the API provider's policies apply.
Product-information pages use no executable JavaScript. The separate free preview tools use only first-party browser code, with no analytics, cookies, storage or network submission. Text in the placeholder checker stays in page memory until cleared or closed. Host request metadata and emails you choose to send may still be processed. This overview is not a finalized sales policy.