Free shipping on every order · 30-day empty-jar guarantee · ships from Madrid in 24h
helix supply
Supplement stacks for deep work, training and sleep. Subscriptions and one-offs.
loading the catalogue
🚚
Free shipping
Every order, tracked, 24h dispatch
↩️
30-day guarantee
Empty jar? Full refund, no questions
🔒
Your money at your bank
Pay from your account or card — the shop never holds it
🧪
Third-party tested
Every batch, published results
Your orders
What happened after you paid · the parcel's journey, answered live by the
logistics service, and the money's journey when a parcel could not go.
nothing yet · buy something above
The ecosystem, live
Every purchase above travels these rails · read from the running system,
every 3 seconds, like the bank's strip under a transfer.
🐘 PostgreSQL
…
ledger rows, last minute
📨 Kafka
…
events published, last minute
🧾 The shop's books
…
orders · subscriptions · invoices
Your cart
Total
What a purchase actually does
Reserves stock in one database and authorises money in another, over HTTP, then
captures on shipment. No money you own is ever involved.
Stock is a second double-entry ledger. A stock account's currency is
UNIT:{product}, so "you cannot oversell" and "you cannot overdraw" are the same rule,
checked once under a row lock. Overselling is not defended against here, it is impossible to express.Live operations
Read straight from the running system, every 3 seconds.
Three audits run continuously. Sum-zero says every transaction balances per currency.
Drift says every cached balance still equals the sum of its entries. The third says the pooled reserved
stock equals the units actually held by live reservations, and it is the only one that can catch a
reservation being settled twice: the other two stay green while the warehouse goes wrong.
Inventory
On hand, held by live reservations, and sold. These three always sum to what was received.
Recent orders
Every order carries the id of a PaymentIntent living in the other service.
Subscriptions
A renewal is not a special case here, it is an order with a derived id, so it inherits the
same reservation, authorisation and idempotency machinery.
The customers are agents
This shop has no human customers, so the customers were built too. A seeded population
browses the catalogue, buys, abandons carts and comes back, driving the same public API a browser would.
Every choice is a pure function of (run, agent, tick, step), so the same seed produces the
same week twice even though agents run concurrently. Order ids are derived rather than random, which is why
replaying a window creates nothing new instead of duplicating orders. One tick of business time is one
hour, so a run of 24 ticks lives a compressed day in a few seconds.
What this honestly proves: that the platform holds up under concurrent traffic and
that its invariants survive. What it does not prove: real conversion rates. These agents were
authored, so they are a load and logic oracle, not a forecast.
A third service, which owns nothing
minimart owns the goods. minipay owns the money. This one owns neither: it has its own
Postgres database, its own Kafka consumer group, and everything it knows it learned from an event.
It cannot query minimart even to settle an argument, because no connection between them exists.
Why the same number appears twice. MRR is stored as MOVEMENTS, never as a
total, for the same reason money is stored as entries: a figure you can overwrite is a figure nobody
can audit. The headline is the sum of every movement ever recorded. The second is that same figure
reached independently, through the projection. If they ever disagree, the drift is shown rather than
hidden, and the movements are the ones to believe.
Where the revenue came from
Growth split into its causes, the only form in which the number means anything.
A renewal is cash, not growth. Three months of renewals do not triple MRR, they
prove it: the revenue was counted the month the subscription began. Counting every payment as new MRR is
the most common way a dashboard shows a business growing 30% a month while the bank disagrees. Renewals
move this number only when the PRICE moved, and then only by the difference, which is why
expansion is a row of its own.
Every movement, and the event that caused it
The audit trail behind the headline. Each row names the exact event key it came from,
which is also the key that stopped it being counted twice when the broker redelivered it.
Provenance is recorded, not assumed. MEASURED means read straight off an event.
DERIVED means computed from measured facts. AUTHORED means seeded by hand. A reporting service that
cannot tell you which of the three a number is will eventually present all three as the same thing.