Case study · Metering · Pricing engine

Segment-level custom pricing

Metered customers wanted to override usage rates on a single subscription, per pricing segment, without forking their catalog. I took it from the first deep-dive to production in about three months.

The problem

Maxio Metering prices usage by segment: a region, a tier, a customer attribute. Every subscription on a price point paid the same segment rates. Customers needed a way to give one account a different rate for one segment without cloning the whole price point and losing the link to the catalog.

How I approached it

I wrote the deep-dive myself: the product goals, the architecture, and the open questions for product and engineering to settle. Once those were resolved, I split the epic into five milestones that could each ship on their own, and wrote an implementation plan for each one. Every plan was reviewed like code before anyone wrote code against it. Then I built the pricing logic and validation myself.

What I delivered

Metering · Pricing engine

Period: Jul – Oct 2026
Role: PM, planner and implementer
Stack: Rails · React · OpenAPI
Shipped: 7 pull requests

Segment rates resolved in pricing brackets and carried forward on renewal

Public API docs and validation on every entry point

Editing segment rates on the subscription's Custom Pricing page

Effective-dated rate changes that split a billing period's usage

A selector for when a rate change takes effect

Line item	Detail
Deep-dive	Wrote the product and architecture deep-dive, got the open product questions answered, and split the epic into five milestones that could each ship on their own.
Milestone plans	Wrote a reviewed implementation plan for each milestone: file-level changes, stub tests, and a decision log recording which option was chosen and why.
Pricing engine	Applied segment-level rates when pricing tiers are worked out, priced inherited segments in the site's currency, and split a period's usage when a rate changes mid-cycle.
Guardrails	Validated segments on signup previews and price-point endpoints, rejected them on paths that couldn't support them yet, and logged an audit entry for every change made through the API.
Plan vs. reality	Kept a changelog of every place the build differed from the plan, such as overrides taking effect immediately instead of at renewal, and fed it back into the plan.

ResultPer-subscription segment pricing for metered customers, from the first deep-dive to production in about three months, with a written record of every design decision.

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