My app has zero customers. Its file format is already public.

LockMargin doesn't have a public build yet. Windows Early Access opens this month, and today the customer count is zero. Last week I published its data format anyway: the schema, the container spec, and a reference decoder that reads both.

People keep asking why I'd do that before launch. The honest answer: the format isn't just infrastructure. It's part of the product promise.

Here's the test I keep applying. If the company disappears tomorrow, can you still read your own invoices? An export button doesn't answer that: exports can be removed, renamed, or quietly degraded to a PDF. A "we take your privacy seriously" page doesn't answer it either. For me, the strongest evidence is two artifacts: a documented format, and working code that reads it without my servers, my keys, or my permission.

So that's what's public now. The file on your machine stays encrypted (AES-256-GCM); what's open is the shape of the container and a decoder that proves the shape is real and not a promise.

I know how this looks from the outside: pre-launch PR, a repo as a press release. I'd argue the opposite, and this is the part I expect pushback on. Publishing the format makes compatibility a visible promise. Once the shape is public, "your old files stay readable" stops being a sentence in my FAQ and becomes something anyone can check me against — including after a v2 I haven't written yet. It is the data-side twin of the license rule I wrote down in an earlier thread: could a v1 buyer reasonably say "I paid for that?" Now the same question applies to their files, not only their license.

I don't yet know whether anyone cares enough to verify any of this. That is the part Early Access should test: do people actually run the decoder, ask about the format, or mention portability when they decide whether to trust the product? The app has no telemetry, so my signal won't be analytics. It will be replies, emails, and the question I already put in the first EA email: which proof did you actually read?
If none of that ever happens, I'll have evidence that I built a proof nobody needed — and I'll say so in the same post where the cohort number lands.

The numbers I can give you today: $49 once when Standard ships, no subscription, no account. The Start tier is free to try: up to 5 clients, 5 projects a month, same encryption, same file. Windows first this month; macOS and Linux coming soon. Zero customers right now.

Three questions, because I genuinely don't have the answers:

1. What's the oldest business file you can no longer open, because the software that made it is gone?
2. If a vendor told you "your data is yours," what would you actually check before believing them?
3. If you've published anything about your product before launch (format, pricing, mistakes): what came back that you didn't expect?

The spec and the decoder:
github.com/vladsh444/lockmargin-data-layer
The longer version, with the reasoning:
lockmargin.com/blog/why-i-published-the-format-before-the-product.html?utm_source=indiehackers&utm_medium=social