DeepSix Dive Log — Pricing Philosophy

DeepSix Dive Log is free

The whole app. No dive cap, no feature gates, no nag screens, no “unlock the good stuff” pop-ups. If you log one dive or ten thousand, it costs you nothing.

This is not a trick. There’s no Pro tier hidden behind a feature you actually need. The thing you downloaded is the thing you get.

If you haven’t configured a tide source or AI key, we’ll occasionally show a small info card explaining your options. One dismissal sticks across all your devices and we won’t bring it up again.

What costs money, and how that works

Two parts of DeepSix Dive Log have real per-use costs that someone has to pay: tides (high-accuracy tidal data near coastlines) and AI features (species identification, tank OCR, narrative generation). For both, you have options.

Tides. The free default is Open-Meteo — worldwide tidal estimates, no signup, no cost, accurate enough for most diving. If you want better data, especially near coasts, two paths exist:

• Bring your own WorldTides API key (worldtides.info). Their free tier covers casual use. You pay them directly; we never see the money.
• Support DeepSix with a Patron purchase — Plankton (US $0.99/month or $9.99/year), or Whale and Megalodon one-time. High-accuracy tides come included, served through our tide relay, so there’s no key to manage.

AI features. These are bring-your-own-key only. Use your Anthropic or OpenAI API key, pay the provider directly at their published rates. We don’t mark up AI costs, we don’t take a cut, we don’t even see what you’re spending.

Costs are usage-controlled. A single critter ID, tank OCR, or narrative generation runs roughly two to three cents at current Sonnet rates — pocket change per dive. Big batch operations are where it adds up: bulk-categorising a 5,000-photo library in one go runs around $100, and a 20,000-photo library closer to $400. Those are conscious decisions, not surprise bills — every batch operation shows you a cost estimate before it runs, and you set spend limits with your provider directly.

We chose BYOK for AI because the costs vary widely between users — annual spend ranges from a few dollars for casual use to a few hundred for a serious liveaboard regular. No subscription tier works for both, and consumable token packs through the App Store eat too much margin to be worth the engineering. Your key, your data, your bill.

Patron tiers

Optional. They exist for users who want to support development. They don’t unlock anything beyond the included high-accuracy tides. Naming is intentional. Prices below are US App Store prices; the app and the App Store listing show them in your local currency.

• Plankton — US $0.99/month or $9.99/year. Tiny, abundant, holds the whole thing up.
• Whale — US $49.99 one-time. Big presence. Tides for life.
• Megalodon — US $99.99 one-time. For users who feel “Whale” doesn’t quite capture their stature.

Naming is the joke; the badge is the receipt — that’s the entire functional difference between them.

Megalodon is the cap. If you’d like to contribute more than that, we’d be genuinely grateful, but we can’t trade you anything in-app for it — Apple’s rules require all in-app benefits to be paid through Apple, and we’d rather respect that than route around it.

What we won’t do

A pricing model is also a list of things you’ve decided against. We’re being explicit so we can be held to it.

• No paywall on the things you came for. Logging and viewing your dives is free, and we have no plans to change that. We won’t promise “forever” — anyone who does is bluffing — but we will promise this: any version you’ve installed keeps working under the terms we offered when you installed it. If we ever introduce paid features, they’ll be genuinely new things, not basics walled off after the fact.
• No paywall on your own data. UDDF and Subsurface export are always free. If you decide to leave DeepSix Dive Log, you take everything with you.
• No advertising. Not in-app, not on the website, not in any future feature. We will never sell your dive log to anyone. The only data that ever reaches us is what you explicitly send — a diagnostic bundle, a wreck or Wonder contribution, or an opt-in Critter Expert report — each shown to you before it leaves your device, and none of it sold or shared. The privacy policy lists every server we run and exactly what each one sees.
• No dark patterns. No fake urgency, no “limited time” tier offers, no shame copy if you choose the free path. The Patron tiers are visible in Settings; you have to go looking for them.
• No gatekeeping community features. If we ever add shared trip pages, public dive site contributions, or species observation upload to research institutions, those will be free regardless of tier.
• No hostage-taking. When your Patron tier ends — whether you cancel Plankton or your card just expires — your dives, photos, and notes are still yours. Tides revert to Open-Meteo. Nothing you entered disappears.

• No abandoning your data. Your dive log remains usable offline and does not depend on our servers existing for basic operation. If we ever stop maintaining DeepSix Dive Log, the source code will be released under the MIT license so other developers can keep it alive or fork it forward. The release mechanism is designed so it does not depend on any individual developer remaining active. The app is free, so this release mechanism is not a gate on shipping; it is being set up now and will follow shortly after launch.

  A handful of external dependencies keep their own open-source licenses (we use libdivecomputer under LGPL and our color-correction algorithm is published separately under GPL); these are documented for any fork maintainer. A fork would technically be a separate app — your existing iCloud-synced data wouldn’t automatically carry over — but our UDDF export preserves everything we know about your dives via documented deepsix: namespace extensions, so a fork willing to read those extensions can ingest your full library with high fidelity. UDDF and Subsurface export are always free; your data stays portable regardless of what happens to us.

Why this model

Three honest reasons.

One: dive logging is a personal record-keeping tool, and personal record-keeping shouldn’t be a subscription. Your dive log will outlive any company, including ours. The model needs to respect that.

Two: DeepSix Dive Log was built by a small independent team of divers, scattered globally, who weren’t happy with the existing options and decided to fix it. We specced what we wanted as divers, built it, and tested it on our own dive logs before sharing it more widely. Early adopters then expanded the project well past its original scope — we started as reef divers, but contributors brought us deco diving, multi-gas, CCR, cave, and concerns we never would have considered on our own. We’re not a venture-backed company chasing growth metrics. We’re trying to make a good thing and let other divers shape it. We’d rather operate sustainably at our real size than chase the largest paying user base we could.

Three: the existing dive logging apps don’t quite hit the mark for us — some are aging, some have stalled, some just aren’t to our taste. The category needs a free, modern, well-built option to consolidate around. We’d rather DeepSix Dive Log be that thing than a small revenue stream nobody really cares about.