Tip pool splitter
A small system that collects what came into the tip pool, applies the split rule the team agreed, and publishes each person’s share with the working shown. It never decides the rule, never moves money, and never rounds in the business’s favour. Seven posts on the same system — one diagram at a time — with a cost breakdown and an engineering reference at the end.
- 01
A tip pool splitter on AWS for a few dollars a month
The whole system on one page — a collector, a splitter and a publisher — with the rule held outside it, because the rule is a decision the system has no business making.
- 02
How the pool and hours are collected
Where each of the three inputs comes from, why cash is a declaration rather than a measurement, and why hours should come from the same source that pays people.
- 03
How the split is computed
The weighted-hours arithmetic, the four rule shapes small businesses actually use, and the two shapes that reliably produce arguments.
- 04
How the rounding remainder is handled
The few pence that rounding always leaves, why they must never go to the business, and the recorded rotation that makes their distribution demonstrably fair over a year.
- 05
How a split gets published
What each person sees, what the whole team sees, why individual shares are not published, and why a correction has to be at least as visible as the original.
- 06
What the tip pool splitter costs
About $1 a month. One Bedrock read per period is the only line that grows; the queue, the table, the mail and the storage are rounding errors. Plus the three ways the bill could surprise you.
- 07
Engineering reference: the tip pool splitter architecture
Same system, drawn purely for engineers. Service names, region, Lambda inventory, IAM scopes, the schemas and the exact model id.
Frequently asked questions
- What is a tip pool splitter?
- A small serverless system that takes what went into the tip pool for a period, applies the split rule the team agreed, and publishes each person’s share with the arithmetic visible. It does not choose the rule and it does not pay anybody.
- Does it decide how tips are shared?
- No. The rule is a decision for the people it affects, and in many places it has legal requirements attached. The system takes a rule that already exists, applies it identically every period, and shows its working.
- Why publish the arithmetic?
- Because tips are the one part of pay that people genuinely do not trust, and the reason is almost never dishonesty — it is that nobody can see the calculation. Showing hours, weights and the pool total removes the doubt at essentially no cost.
- How are rounding differences handled?
- Rounding to the penny always leaves a remainder. It is distributed rather than kept, in a rotating order recorded in the period, so it never quietly accumulates anywhere.
- What does it cost to run?
- A couple of dollars a month. It runs weekly over a few dozen rows. See part six.