The catalog · SaaS

Dunnable

Recover the failed card

Next.js + PostgresDifficulty 2/5Suggested $29/moAny subscription business
Smoke-tested to a running MVP, or we fix it. No card to start.
84
UIQ score
GO
Build Dunnable · free to start, no card
1
Pick a scored ideaEach idea is graded 0 to 100 with the full case that earned the number, so you build on evidence.
2
Build it with your agentA ten-phase kit feeds your coding agent one prompt at a time, from empty folder to a running MVP.
3
Launch and get paidShip it live, then the launch kit helps you land the first users who prove it.

Problem

A card expires and a paying, happy customer silently becomes a former customer. The default retry fires three times into the void and gives up. The customer never knew, and the founder counts it as churn and looks for a product reason that does not exist.

Why now

Involuntary churn quietly became a large share of total churn as subscription businesses multiplied, and card networks now expose enough decline detail to retry intelligently rather than blindly.

Solution

Retry on the schedule the decline code actually warrants, since insufficient funds and an expired card want completely different treatment. Reach the customer where they will see it, and make updating the card a single tap rather than a login.

Who it is for

Any subscription business losing revenue to failed payments, which is all of them, though only some have noticed. The founder who buys it has usually just discovered that a chunk of what they logged as churn was a card expiring rather than a customer leaving. They were looking for a product reason that did not exist. Once seen, it is hard to unsee, because the lost revenue is from customers who were happy and never chose to go.

What you could earn from Dunnable

Say you build Dunnable and charge your own customers $29 a month, the price the score suggests. The numbers below are the revenue that would come from them. This is money you earn, never a fee you pay UpgradIQ, and we never take a cut. It is arithmetic off the price, not a promise the customers arrive on their own.

10customers paying you $29/mo$290/moyou earn · $3,480 a year
50customers paying you $29/mo$1,450/moyou earn · $17,400 a year
100customers paying you $29/mo$2,900/moyou earn · $34,800 a year

See what Dunnable produces

It retries on the schedule the decline code actually warrants, since insufficient funds and an expired card want completely different treatment, reaches the customer where they will see it, and makes updating the card a single tap.

Dunnable · recovery queue
CustomerAmountDecline reasonNext retryStatus
Acme Co$290Insufficient fundsin 3 daysRetrying
Lumen Ltd$49Expired cardEmailedAwaiting card
Byte Inc$120Do not honorPausedNeeds contact
Nova LLC$290Insufficient fundsRecoveredPaid
3 of 4 on track$460 at risk
Retry cadence matched to the decline code · one tap updates the cardSend update links

Your build kit for Dunnable

Start the build and the kit opens two steps in, then drip-feeds the rest one phase at a time. Every phase is a copy-paste prompt for your agent with its own verification before the next unlocks, so Dunnable moves from an empty folder to a running MVP without you ever holding the whole plan in your head.

Progress saves across every device, and the workspace always reopens on the exact step you left, so a build that runs over several weeks survives them instead of dying in a browser tab you eventually close.

Idea and stack are already checked, so you open at 2 of 10
10phases to MVP
2/5difficulty
Next.jsprimary stack
Dunnable · build kit
Idea chosenDone
Stack selectedDone
3Scaffold the stackNext up
4Data model and sign-inLocked
5Core feature, end to endLocked
6Monetization wiringLocked
7Test and hardenLocked
8Polish and deployLocked
9Launch-day toolkitLocked
10First 10 usersLocked

How you actually build it

Connect your coding agent once. It pulls the current phase straight from your kit over MCP: the exact prompt, the outcome to aim for, and the check to run before it moves on. You review and ship, it does the typing.

No copy-paste juggling, no thread to lose. The kit stays the single source of truth, and your agent works through it one phase at a time, verifying its own work at each step before the next phase is unlocked.

Start free, run phase 1Free account, no card. The first phase prompt unlocks the moment you start, right in your workspace.
agent · MCP
$ get_current_phase dunnable
Phase 3 of 10: Scaffold the stack
Outcome: The project builds, runs locally, and its health route answers 200.
Check: Run the dev server. `curl` the health route and show the 200. Run the build and show it passing with zero type errors. Confirm `.env` is gitignored: `git status` must not list it.
building · scaffolding Next.js, the data layer, the health check
dev server up · /api/health returns 200 · build passes
$ mark_phase_complete scaffold
Done · 30% complete · next: Data model and sign-in
phase 4 unlocked · the agent asks for the next prompt

Take the context file, free

This is the AGENTS.md that keeps your coding agent on scope for the entire build: what Dunnable is, who it is for, the stack, the non-goals, and the rules it must follow. Copy it into your project now, no account needed, and your agent is briefed before you write a line.

AGENTS.md · dunnable
# Dunnable

Recover the failed card

## What this is
Retry on the schedule the decline code actually warrants, since insufficient funds and an expired card want completely different treatment. Reach the customer where they will see it, and make updating the card a single tap rather than a login.

## The problem it solves
A card expires and a paying, happy customer silently becomes a former customer. The default retry fires three times into the void and gives up. The customer never knew, and the founder counts it as churn and looks for a product reason that does not exist.

## Who it is for
Any subscription business losing revenue to failed payments, which is all of them, though only some have noticed. The founder who buys it has usually just discovered that a chunk of what they logged as churn was a card expiring rather than a customer leaving. They were looking for a product reason that did not exist. Once seen, it is hard to unsee, because the lost revenue is from customers who were happy and never chose to go.

## Stack
Next.js + Postgres

## Non-goals
Do not build features outside the core job above. This product exists to do one
thing well. Every extra feature is a reason it does not ship.


## Rules for the agent
- Build one phase at a time. Do not run ahead into later phases.
- Validate input at every boundary where data enters.
- Never put a permission or plan check in client code.
- Ask before adding a dependency that a few lines would cover.
- If something is ambiguous, say so rather than inventing a requirement.

---
Context file from UpgradIQ · idea dunnable · prompts kit-v4

Then start free to get the ten-phase kit and run the first prompt.

The path to a running MVP

Phases 1-4

Foundation

Scaffold the stack, then wire the data model and sign-in. It is the skeleton Dunnable stands on, and it goes up in an evening rather than a lost week of config.

Phases 5-6

The product

Build the core feature end to end, then wire how it charges. This is where Dunnable finally turns into something that a stranger will actually pay you for.

Phases 7-10

Ship it

Test and harden, deploy it live, then open the launch-day toolkit that lands the first ten users who prove it.

Is Dunnable for you?

A good fit if
  • You want revenue reasonably soon, not a science project
  • You can give it evenings and a couple of weekends
  • You can reach Any subscription business
You have read the free case, the hard part4 of 7 sections done

The 3 sections that decide whether you should actually build it, plus the full kit, are one click away.

Pro

3 more sections decide whether you build Dunnable

You have the case and the plan. Pro opens how it makes money, the one risk that kills it, and the build notes, plus the 10-phase kit that takes Dunnable to a running MVP, on this idea and all 200.

How it makes money

Main risk

Build notes

What is free here, and what Pro unlocks

The problem, timing, solution and buyerFree
How it makes money, priced and modelledPro
The full UIQ 84 and all eight sub-scoresFree
The one risk most likely to kill itPro
Stack, difficulty and suggested priceFree
The 10-phase kit to a running MVPPro

Frequently asked

Is Dunnable actually validated?

It scored UIQ 84 with a GO verdict, weighed across eight sub-scores on the same rubric as every idea. GO means 75 and above, so demand and buildability were judged, not guessed.

What stack does it use?

Dunnable is built on Next.js + Postgres, chosen because a coding agent can carry most of it. You are not fighting infrastructure, you are shipping the feature that matters.

How long to a running MVP?

The kit is ten phases, drip-fed one at a time so you always know the single next step. An evening and a weekend for the lighter builds, a few focused weeks for the deeper ones.

What does the $29 a month mean?

It is the price the model suggests Dunnable could charge its own customers, not a fee to us. It is here so the money question is answered before you build, not after.

Which agent do I need?

Any capable coding agent: Claude Code, Cursor, Lovable, or Bolt. Every phase is a copy-paste prompt with its own check, so the agent does the typing and you keep the judgement.

What is free versus Pro?

The whole case above is free: the problem, timing, solution, buyer, and the full score. Pro adds how it makes money, the one risk that could kill it, and the full kit that carries Dunnable from an empty folder to a running MVP.

More like Dunnable

All 24 SaaS ideas
3 more sections

Build Dunnable, not just read about it

You have the problem, the timing, the solution and the buyer. A plan opens how it makes money, the risk that kills it, and the kit that takes it to a running MVP.

Start building Dunnable
Today's idea is free, no account