Codemix for engineering managers

Stop making your best engineers the product memory.

Teams slow down when the product lives in a few heads. Every new hire needs a tour. Every change needs a back-channel check. The people who know the system best get turned into a helpdesk.

AI coding agents make that worse if they're briefed from tickets and vibes. They fill in the missing product context from nearby code. Sometimes that's right. Often it's just confident.

Codemix turns the real product into shared context for engineers and agents. New people ramp faster. Change impact is visible earlier. The team stops waiting for whoever remembers why it works this way.

Demo

Multi-tenant analytics SaaS platform

Work in motion

  • Proposals: 2
  • Reviewing: 1
  • Approved: 1
  • Tasks: 5
  • Running: 1
  • Ready: 3
  • Blocked: 1
  • Completed: 3

Model inventory

  • Requirements Intent: 8
  • Concepts Domain: 14
  • Personas Audience: 3
  • Flows Journeys: 9
  • Screens Surfaces: 6
  • Stories Behavior: 18
  • Systems Mechanics: 5

Integrations

  • 3/4 live
  • GitHub connected
  • MCP connected
  • CLI connected
  • Slack ready

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.

The coordination tax

Product knowledge that lives in heads doesn't scale.

Your team is not slow. The information they need is locked in a few people, and extracting it takes time nobody has.

Documentation usually doesn't fix this. Wikis go stale. Runbooks get written once. Codemix derives the product model from the codebase, so the context stays current without manual upkeep.

The bus factor problem

One engineer knows billing. One knows permissions. When they are away, the team either waits or guesses.

Onboarding takes months, not weeks

New engineers spend too much of their first quarter extracting context from people who are already overloaded.

Change impact is invisible until it isn't

The ticket looks small. Then implementation finds billing, permissions and three flows nobody mentioned.

Senior engineers become bottlenecks

The people who know the product best spend their time explaining it. That is useful once. After that it is a tax.

Understand the product

See what your team is actually building

Most teams have two products: the one people describe and the one the code actually implements.

Codemix derives a map of concepts, flows, commands and screens from the codebase. What you see is what exists, not what someone remembered to document.

Reduce knowledge silos

Give the whole team access to product context

When product knowledge lives in a few heads, everyone else has to interrupt those heads to move.

Codemix makes that context queryable. Engineers get answers grounded in the product model, not stale tickets or local guesses.

Proposal

When a customer upgrades their plan, how long does it take for their new limits to apply?

Right now, they don't apply automatically. Stripe notifies Stratum when a subscription changes, but the product doesn't react — so a tenant can pay for a higher tier and still be on their old limits until someone manually updates the database.

Want me to put together a proposal for closing this?

Yes. Make sure it covers upgrades, downgrades, and cancellations.

Proposal ready. Here's what changes for tenants:

  • Upgrade: new limits apply before their next action in the product
  • Downgrade: access steps down at the end of their current billing period
  • Cancellation: they keep full access until the period they've paid for expires, then move to the free tier

I've broken the work into 5 tasks that can run in parallel once the core notification handler is in place.

Assess change impact

Know what a change will touch before implementation starts

The expensive surprises are the ones that looked small in the ticket.

Codemix shows the concepts, screens, flows and dependencies involved before work starts. Scope conversations get a lot more honest.

Task plan

React to plan changes in real time

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 Stripe reports a subscription change, the product reacts immediately: the tenant's access updates, and everyone on that account sees the correct limits before their next action.

Behavioral change (what must now be true)

  • 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. Each notification describes a change in subscription state — an upgrade, a downgrade, or a cancellation.
  2. Verify each notification is genuine — Before acting on any notification, the product confirms it actually came from Stripe. Notifications that can't be verified are rejected, causing Stripe to retry delivery.
  3. Apply each notification exactly once — Under normal conditions, Stripe may send the same notification more than once. The product records each notification it has acted on, so duplicates have no effect.
  4. Update tenant access — Once a notification is verified and accepted, the tenant's access level is updated to reflect their current plan. Upgrades apply immediately; cancellations apply at period end.
  5. Confirm the behaviour end to end — Tests verify the product-level outcomes: that upgrades take effect, that cancellations move tenants to the free tier, that duplicates are safely ignored, and that forged notifications are rejected.

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

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

Keep delivery grounded

Make sure what ships matches what was decided

Agents and engineers make decisions during implementation. Some of those decisions are product decisions.

Codemix compares what was built with what was approved. Mismatches surface before they become review drama or production behaviour.

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. Resolve them here, and the work that follows is far less likely to need rethinking.

How it works

How Codemix carries context through the full lifecycle

  1. 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

  2. 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.

  3. 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.

  4. Write the tasks
    Once the proposal is approved, Codemix turns it into implementation work. Send it to Linear or Jira, hand it to a coding agent, or let humans and agents split it up.

  5. Answer questions mid-build
    Implementation always uncovers questions. Codemix gives engineers and coding agents answers from the product model, so they don't have to guess from a ticket title or a nearby file.

  6. Review what changed
    Codemix reviews the code against the product decision, not just against style, tests, or neighbouring code. That's where a lot of agent mistakes hide.

  7. Ship, then update the spec
    Shipping often reveals details nobody saw at planning time. Codemix helps fold those decisions back into the spec, so the source of truth doesn't go stale the moment the PR lands.

  8. Bring the context forward
    Bring in bugs, customer feedback, support notes, and product signals. The next proposal starts with the context you already built, instead of another round of archaeology.

Pricing

Codemix pays for itself on day 1.

Build better apps with Codemix faster than ever before. Save time, stop wasting tokens and keep humans in control.

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 without committing to a subscription.

  • Try for just $20
  • Upgrade to Pro for Slack, hosted code analysis, invites, and code review

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

  • $50 per user / month
  • $500 per user yearly. 2 months free.

Enterprise
For teams that need custom terms, SSO, compliance, or support. Contact sales for custom pricing.

Ready to move faster?

Codemix gives engineering teams the shared product model they need to move without constant context downloads. Senior engineers build instead of explain. New hires start sooner.