Codemix for software architects / platform teams

Build the right system. Not just a tidy diagram.

A technically sound architecture can still fight the product. The service boundary looks clean. Then every real feature has to cross it.

The missing input is domain understanding. Boundaries drawn without it split concepts that belong together. Platform abstractions built without it get worked around. This is very predictable, which somehow doesn't stop it happening.

Codemix gives architects and platform teams the product's actual domain model: concepts, flows, constraints and how they relate. Make structural decisions from the product, not the diagram.

Demo

Multi-tenant analytics SaaS platform

Work in motion

Model inventory

Integrations

Build Checklist

TECHNICAL READINESS

• All critical API endpoints covered by integration tests
• Rate limiting in place on public endpoints
• Database backups verified and restore tested

PRODUCT & ONBOARDING

• Onboarding flow end-to-end tested with external user
• Help docs cover the top 5 user questions
• Feedback channel (Slack / email) ready and monitored

Activity

1. Proposal sent to review - 3/10/2026
2. Task plan generated from approved scope - 3/10/2026
3. Project phase changed from explore to build - 3/10/2026

Project overview

See everything in flight, at a glance. The overview surfaces every active proposal, running task, and recent conversation in one place — no status updates required. Codemix keeps it current as work progresses, so anyone on the team can see what's happening and where things stand.

Next

Good technical reasoning is not enough without product understanding.

Architectural decisions can be technically reasonable and still wrong for the product. A boundary can split a domain concept in half. A platform abstraction can make product work slower.

The issue is not competence. It is context. Without the domain model, architects optimise for the wrong things. Codemix puts the product model in the room before the decision gets made.

Boundaries that split the domain

A service boundary can look clean and still split a concept that belongs together. Product teams pay for that forever.

Platform abstractions nobody uses right

Infrastructure designed without product context gets bent, worked around and eventually replaced by the teams it was meant to help.

Optimized for the wrong workloads

Scalability and resilience patterns are easy to apply in the wrong place when you don't know where the domain actually concentrates load.

Architecture that fights the domain

When technical structure fights business structure, every feature has to bridge the gap. That friction compounds.

Start from the product

You cannot draw good boundaries without understanding the concepts and how they relate.

Codemix surfaces concepts, commands, flows and constraints from real code. You reason from the product domain before decisions harden into contracts.

Proposal Review Task

React to plan changes in real time

Ready to execute from the accepted proposal.

Overview

Stratum currently has no way to respond when a customer's subscription changes. Stripe sends a notification every time a plan is upgraded, downgraded, or cancelled — but the product ignores them. This means a tenant's access level in the product can be out of step with what they're actually paying for.

This work makes billing changes real:

• When a customer upgrades, their new plan limits apply before their next action in the product.
• When a customer downgrades, their access steps down at the end of their current billing period.
• When a customer cancels, they keep full access until their paid period expires, then move to the free tier.
• If the same billing notification arrives more than once, the tenant's access is updated exactly once.
• If a notification can't be verified as genuine, it is rejected and Stripe will automatically retry.

What to implement

1. Receive plan change notifications — The product listens for billing notifications from Stripe.
2. Verify each notification is genuine — Before acting on any notification, the product confirms it actually came from Stripe.
3. Apply each notification exactly once — Record each notification it has acted on.
4. Update tenant access — Update the tenant's access level based on verified notifications.
5. Confirm the behaviour end to end — Tests verify the product-level outcomes.

Out of scope

• Sending email notifications when subscription state changes
• Changing which features are available on each plan
• Reacting to payment failures or invoice events
• Registering the notification endpoint with Stripe

Task Plan

Once a proposal is approved, Codemix breaks it into parallelizable tasks and executes them autonomously. The task plan keeps every behavioural commitment visible while the build is underway.

Next

Review with product context

Assess change impact in terms the product actually cares about. Technical impact is only half the review. The other half is product impact. Codemix maps proposed changes to affected concepts and flows before implementation starts.

Tasks

5 pending/3 done

Pending Tasks

1. Accept and verify plan change notifications (In progress)
2. Verify notifications are genuinely from Stripe (Ready)
3. Prevent the same notification from being applied twice (Ready)
4. Update tenant access when their plan changes (Blocked)
5. Confirm the behaviour end to end (Ready)

Completed Tasks

1. Enforce per-tenant usage limits (Completed)
2. Keep tenants isolated from each other's usage (Completed)
3. Surface usage limits in API responses (Completed)

Build for how teams actually work

Design platform abstractions that fit real product workflows. Platform teams often build from technical needs and assumptions about product teams.

Codemix shows the workflows, constraints and domain concepts the platform has to serve.

Proposal Review Suggestions

Resolve ambiguous behaviour before accepting the proposal.

1 open 1 approved 1 rejected

• The proposal doesn't specify which part of the product is authoritative when a plan changes.
• If Stripe sends the same notification twice, the proposal doesn't guarantee that only the first delivery has any effect.
• New billing signals from Stripe would be missed silently.

Proposal Review

Catch the problems before the work starts. Codemix flags gaps in the proposal — ambiguities, missing cases, or things that conflict with how the product already works.

How it works

Start with a conversation or from code

Chat with Codemix if you're still at the idea stage, or import your existing codebase.

A product baseline
Start with an interview or connect the existing codebase.

Model the product

Codemix builds a working model of the product: the concepts, screens, actions, rules, edge cases, and decisions that explain how it is meant to behave.

Shape the change

Before implementation starts, you can ask questions, edit the spec, and turn a rough idea into a concrete proposal for what should change.

Write the tasks

Once the proposal is approved, Codemix turns it into implementation work.

Answer questions mid-build

Implementation always uncovers questions. Codemix gives engineers and coding agents answers from the product model.

Review what changed

Codemix reviews the code against the product decision, helping to catch mistakes.

Ship, then update the spec

Shipping often reveals details nobody saw at planning time. Codemix helps fold those decisions back into the spec.

Bring the context forward

Bring in bugs, customer feedback, support notes, and product signals.

Pricing

Codemix pays for itself on day 1.

Pay As You Go

• $50 pro user / month, for teams
• 20k credits per pro user / month

Solo

• For one-person workspaces that want to try Codemix
• Try for just $20

Pro

• Self-serve pricing for teams ready to start now.

Enterprise

• For teams that need custom terms, SSO, compliance, or support.

Ready to design from the product?
Stop making structural decisions from half the map.