Welcome to Keysat.
Keysat lets independent software creators sell their work on their own terms. You ship software — open source, closed source, free / paid versions, whatever fits — and Keysat handles the buy page, payment via BTCPay, and a signed license for each buyer.
How you use that license inside your software is up to you: a one-time purchase to unlock the whole app, a free + paid split with specific paid features, a tip-jar style supporter badge — all legitimate. The licensing layer is a primitive, not a script.
These docs cover both ends:
Architecture
Keysat is the licensing layer sitting on top of your existing payments stack. Three boxes:
- BTCPay Server — takes the payment. On-chain Bitcoin or Lightning, settling to your wallet. Lives on your Start9.
- Keysat — your private licensing service. Holds the Ed25519 signing key. Hosts the public purchase URLs at
/buy/<product>. Listens for BTCPay payment webhooks and issues a signed license on each settlement. Lives on your Start9. - Your software — the thing you sell. Ships with the Keysat public key embedded at compile time. On startup it reads the user’s license and verifies the signature offline. No network call.
The key word is offline. Once a license is issued, your software does not need to phone home to verify it. The verification is a pure function of the license bytes and the public key. This is the same model used by signed JWTs, except wrapped in a small fixed-width format that’s comfortable to print on a receipt.
Why offline matters. Online license servers are a single point of failure for every customer who ever bought your software. With Keysat, if your Start9 disappears tomorrow, every previously-issued license still verifies. That’s sovereignty.
Products & policies
You declare two things in Keysat: products and policies.
A product is the thing you sell — "Bitcoin Ticker Pro", "Aurora Plugin", whatever. It has a slug, a display name, a description, and a price (sats / USD / EUR). Each product also carries an entitlements catalog — the typed list of feature slugs your software cares about, plus their display names and descriptions. Policies pick entitlements from this catalog.
A policy is a license template attached to a product. It specifies:
| Field | Meaning |
|---|---|
duration_seconds | How long the license is valid. 0 means perpetual. |
grace_seconds | Extra time after expiry before the verifier rejects. |
max_machines | Seat cap. 0 means unlimited. |
is_trial | Sets a TRIAL bit so your app can show a "trial" banner. |
is_recurring + renewal_period_days | Auto-renew on a cycle (weekly / monthly / annual / custom). The daemon mints a fresh invoice + signed license per cycle. |
entitlements | Subset of the product’s catalog this policy grants. Baked into the signed license. |
metadata.marketing_bullets | Operator-authored ✓ items rendered on the buy-page tier card. Pure marketing copy — not enforced. |
metadata.hidden_entitlements | Slugs the license still grants but the buy-page card hides — useful when a higher tier uses "Everything in X, plus:" copy and doesn’t want to repeat implied entitlements. |
A product can have one policy or many. Multi-tier ladders (think Basic / Pro / Max) are first-class: when a product has two or more public policies, the buy page renders a tier picker and the buyer chooses before paying. The displayed tier is selected from a ?policy=<slug> URL hint, then the highlighted ("most popular") policy if any, then the cheapest. Tier ordering on the picker is operator-controlled via drag-and-drop in the admin UI (or tier_rank in the API).
You can also attach private policies for manual issuance — e.g. a longer-duration "Lifetime" comp for conferences, a richer-entitlement "Internal" tier for support cases. Private policies don’t appear on the buy page; the admin API issues them directly.
Discount codes
Four kinds:
| Kind | What it does |
|---|---|
percent | Buyer appends ?code=FOUNDERS50 to the purchase URL; price drops by N%. |
fixed_sats | Like above, but a flat amount comes off. Denominated in the code’s discount_currency (sats / USD / EUR), so the same code can sit on top of multi-currency products. |
set_price | Overrides the tier price with a flat number, regardless of base. Useful for "first 100 buyers at 25k sats" promos where you want the price to be a specific round number rather than a percentage off. |
free_license | No payment at all. Buyer redeems the code via POST /v1/redeem and gets a signed license back. |
Codes can be capped at N uses, dated to expire, restricted to one product (and optionally to a subset of policies on that product — e.g. "applies to Pro and Max but not Basic"), and tagged with a referrer label so you can see which campaign drove which sales in the audit log.
Codes can also be marked featured — a "launch special" mode. A featured code:
- Renders a diagonal "LAUNCH SPECIAL" ribbon + struck-through original price on the matching tier cards on the buy page.
- Auto-applies for buyers who don’t type any code, with the input pre-filled so they can see what’s been applied.
- Stops surfacing once it hits its
max_usescap or expires — the ribbon disappears and pricing reverts to standard automatically.
Operator-typed codes always take precedence: a buyer who pastes a non-featured code in the form gets that code instead of the auto-applied featured one.
Revocation strategy
This is the one piece of the architecture that requires a design decision from you.
Because verification is offline, a license that was once issued continues to verify forever — even if you mark it as revoked in the admin UI. The verifier in your app doesn’t know about your admin actions.
You have three options:
- Don’t support revocation at all. Many indie developers do this. Once a key is sold, it stays valid. Refunds are still possible — you send sats back via BTCPay; the key still works but the customer agreed to stop using it.
- Periodic online check. Your app fetches a small revocation list from your Keysat (or a CDN you point at it) once a week / month. Adds a "soft-online" requirement.
- Short-lived licenses with renewal. Issue 30-day licenses; the app fetches a fresh signed token before expiry. Recurring renewals are first-class in v0.2 — define a policy with
is_recurring=true+renewal_period_daysand Keysat handles the cycle (invoice → settle → re-sign → webhook).
You decide the policy. Keysat doesn’t force a particular revocation model. The default is no revocation — that’s the simplest, sovereign-by-default choice. If you need stronger guarantees, layer them on with the patterns above.
Operator tiers
Keysat itself ships under a tiered self-license. The daemon runs out of the box at the free Creator tier with caps that are generous for a solo developer; paid Pro and Patron tiers lift caps and unlock recurring billing + the Zaprite payment gateway. Caps are enforced by the daemon at create-time only — existing resources are always grandfathered if you downgrade.
As of this writing, Creator caps at 5 products / 5 policies per product / 10 active discount codes, and Pro / Patron are unlimited. The exact tier list, prices, entitlements, and any active launch-special discount are operator-controlled on the master Keysat and may change — the canonical sources are:
- The live tier cards on keysat.xyz (rendered dynamically from the master Keysat).
- The pricing page on these docs for the human-readable breakdown.
GET https://licensing.keysat.xyz/v1/products/keysat/policiesfor the machine-readable shape (entitlements, marketing bullets, featured discount, etc.).- Your local daemon’s
GET /v1/admin/tierfor current tier + caps + usage from inside the admin context.