Appearance
Crest — Product Vision
| Product | Crest — Personal Finance App |
| Document version | 0.3 (Draft) — Crest is local-first: the app is open to everyone on their own device; sync and sharing are for invited people |
| Date | 2026-10-05 |
| Owner | Reizkian Y. Radityatama |
| Status | Draft — pending review |
This is the first document to read. It explains why Crest exists and what it believes. The other documents describe what Crest does (0.1), how people use it (0.2), and how it is built (0.3). When a design decision is unclear, choose the option that best serves this vision. This document explains intent; it does not define behaviour. Where it seems to differ from the Business Requirements Document, the requirements and business rules (BR-*) are the truth.
1. Why Crest exists
Most people work hard for their money, yet at the end of the month many can't say where it went. Money leaves in many small, forgettable moments: a coffee here, a delivery there, a parking fee, a top-up. It is spread across cash, several banks, e-wallets, and credit cards, so no single place shows the whole picture.
Without that picture, people make money decisions on feelings: "I think I can afford it." "I don't know why I'm always short before payday." "We should save more, but from where?" The result is stress, arguments at home, and savings that never grow.
Crest exists to help people see their money clearly, so they can decide on purpose instead of by accident.
We believe the simplest habit makes the biggest difference: write down what comes in and what goes out. Crest makes that habit fast, meaningful, and worth keeping.
2. Our mission
Help people build the habit of recording their finances, and turn those records into understanding, calm, and better choices.
3. Why recording your finances matters
Recording every transaction can feel like a chore. Here is why it is worth it, and what Crest wants every user to experience.
| Benefit | What it means in daily life |
|---|---|
| 1. You finally know where your money goes | After one month of recording, you see real numbers instead of guesses. Most people are surprised: the biggest leaks are rarely the big purchases. |
| 2. Small leaks become visible | Coffee, snacks, food delivery, parking, and small top-ups feel cheap one at a time but add up to a large monthly amount. Seeing the total is often where the easiest savings are. |
| 3. You can plan instead of react | With a record of past months, you can set budgets that fit your real life, and you know before payday whether you're on track, not after. |
| 4. You pay your future self first | When saving and investing are planned like any other expense, they happen every month instead of "if something is left over." |
| 5. Surprises stop being surprises | Annual and irregular costs (vehicle tax, school fees, Lebaran, insurance premiums) show up in your history. You can set a little aside each month, so they don't break your budget when they arrive. |
| 6. Less stress, more calm | Uncertainty is what makes money stressful. Knowing your numbers, even when they're not perfect, replaces worry with a plan. |
| 7. Better conversations | Couples and families can talk about money using facts, not feelings. A business owner can see how a staff fund is used without micromanaging. |
| 8. You can see your progress | Net worth, savings goals, and falling debt show that your effort is working, which makes the habit easier to keep. |
| 9. Your decisions get better | "Can I afford this?" becomes a question with an answer: you can see what it would replace. |
4. What Crest believes
These principles guide every feature and design decision.
- Recording must be effortless. If adding a transaction takes more than a few seconds, people stop. Speed beats completeness (BO-2: under 10 seconds).
- Classify by purpose, not by place. A category answers "what was this money for?", not "which shop took it?" (see §5).
- Show what you can control. Separate fixed commitments from everyday needs and from choices, so people know what can shrink when money is tight.
- No judgment. Crest shows facts, not lectures. Enjoying life is part of a healthy budget; the goal is spending on purpose, not spending nothing.
- Real life, not a textbook. Crest fits how people actually live: cash and e-wallets, motorbikes and ride-hailing, supporting parents, religious giving, community contributions, and shared money with a partner or staff.
- Your money, your data. Crest never sells data, shows ads, or moves money. Privacy is a feature, not a setting. The app works fully on your own device, so your records can stay with you and nowhere else.
- Open to everyone on their own device, cloud for people we know. Anyone can use Crest for free, with no sign-up, because it costs nothing to run on their own phone. The cloud part (sync across devices, shared spaces, a server copy as backup) runs on a small server that the owner pays for, so it is invite-only, free, and run with care.
4.1 Two ways to use Crest
| On your device (local mode) | Connected (invited people) | |
|---|---|---|
| Who | Anyone | People the owner knows and approves |
| Sign-up | None: open Crest and start | Request access, then activate a login |
| Where the data lives | Only on your device | On your device and on Crest's server in Indonesia |
| What it gives you | Everything for recording, budgets, and understanding your money | The same, plus several devices, shared spaces, a server backup, and email |
| Who looks after a backup | You: save a backup file | The server, and you can still save a file |
The first version of Crest is the local one. It needs no server, so it can be used while the cloud part is still being built.
5. Example: classifying spending by purpose
This section is an illustration, not a specification. It shows how the principle "classify by purpose, not by place" can work in practice. Crest's actual behaviour (default categories, how transfers, credit cards, and savings are counted) is defined in the Business Requirements Document; where this example differs, the business rules win.
A good set of categories answers a clear question for each category and supports a real decision.
5.1 Why this classification works
It's organized by purpose, not by where you pay. Each category answers "what was this money for?" rather than "which shop took it?" A supermarket trip is recorded by what it was mostly for (e.g. Food & Drinks), not under the store's name, so the budget reflects real life.
It separates what you can control from what you can't. The categories move from commitments to choices:
Group Categories Fixed commitments Housing, Utilities, Insurance, Debt Payments, Vehicle Ownership Needs that vary Mobility, Food & Drinks, Household Supplies, Healthcare, Children & Family Choices Lifestyle, Giving & Social Future and surprises Financial Goals, Irregular / Annual When money is tight, users can see immediately which categories can shrink and which can't.
It fits real everyday life, not just a textbook household. It covers people who own a car or motorbike, people who rely on ride-hailing, people who cook, and people who eat every meal outside. It includes costs many budgeting apps forget, like supporting parents, religious giving, and community contributions.
It makes hidden spending visible. Small, frequent costs like coffee & snacks, food delivery, and parking get their own lines. They rarely feel expensive in the moment, but they add up, and seeing them is where users find the easiest savings.
It has the right level of detail. Fourteen categories with a few sub-categories each are detailed enough to be insightful, but not so detailed that logging an expense feels like work. Users who want less detail can track only at the category level.
5.2 Why each category exists
| Category | Why it exists |
|---|---|
| Housing | The largest fixed cost for most people. Keeping it on its own shows how much of income goes to a roof over your head, one of the most important numbers in personal finance. |
| Utilities | Recurring bills that keep a home running. Mostly fixed, but can be reduced through usage (electricity, data plans), so they're separate from Housing. |
| Insurance | Protection costs. Grouping health, life, and property insurance shows the total price of protection in one place. Vehicle insurance is the exception and lives under Vehicle Ownership. |
| Debt Payments | Shows how much income is already committed to past spending. If this grows too large it limits everything else, so it must be clearly visible. (Paying a credit card bill is a transfer, not spending, per BR-18; the purchases were already counted when made.) |
| Vehicle Ownership | Answers "what does it cost to have this vehicle?" Financing, insurance, tax, maintenance, repairs, and parts are in one place, so users see the true yearly cost of owning a car or motorbike. That's why vehicle insurance is here rather than under Insurance. |
| Mobility | Answers "what does it cost to move around?" Fuel, tolls, parking, and all other ways of getting around. Users can compare driving themselves with ride-hailing or public transport on a fair basis. |
| Food & Drinks | Works for everyone, whether they cook or eat out. Daily meals are treated as a need, not a luxury. Coffee & snacks and delivery are separate because they're common leaks. Social dining is the part that is truly a choice. |
| Household Supplies | Non-food things a home uses up. Separating these from food keeps the food numbers accurate. |
| Healthcare | Out-of-pocket medical costs. Separate from Insurance: insurance is what you pay to be protected; healthcare is what you pay when you actually need care. |
| Children & Family | Covers people who depend on the user, both children and parents. A major cost in many households that deserves its own space. |
| Lifestyle | Spending that makes life enjoyable but isn't essential. Making it visible helps users enjoy it without guilt when the budget allows, and cut it first when needed. |
| Financial Goals | Encourages paying your future self first instead of saving whatever happens to be left over. (Moving money to your own savings financial account is a transfer, not spending, per BR-2; progress is followed with savings goals, FR-BUD-4/5.) |
| Giving & Social | Religious giving, charity, gifts, and celebrations are often large and meaningful, but easy to forget in budgets. A dedicated category helps users plan for them. |
| Irregular / Annual | Costs that come once or twice a year and feel like surprises. Seeing them helps users set aside a little each month so they don't break the budget when they arrive. |
5.3 Example categories and sub-categories
An example of how a space's categories could look for an Indonesian household. It is not the default list; Owners of each space shape their own categories (FR-CAT-2). Indonesian examples are in brackets.
| Category | Sub-categories |
|---|---|
| Housing | Rent & Boarding [kos] · Mortgage [KPR] · Service & Security Fees [IPL] · Property Tax [PBB] · Maintenance & Repairs · Furniture & Appliances |
| Utilities | Electricity [PLN] · Water [PDAM] · Cooking Gas [LPG] · Home Internet · Mobile & Data |
| Insurance | Health Insurance [BPJS Kesehatan, private] · Life Insurance · Property Insurance · Other Insurance |
| Debt Payments | Personal Loans [KTA] · Paylater & Installments [cicilan] · Loans from Family & Friends · Interest & Late Fees |
| Vehicle Ownership | Vehicle Financing · Vehicle Insurance · Vehicle Tax & Registration [pajak, STNK] · Service & Maintenance · Repairs & Parts |
| Mobility | Fuel · Tolls · Parking · Ride-hailing & Taxi [ojek online] · Public Transport |
| Food & Drinks | Groceries · Daily Meals · Coffee & Snacks · Food Delivery · Social Dining |
| Household Supplies | Cleaning Supplies · Toiletries · Laundry · Kitchen & Home Items · Household Help [ART] |
| Healthcare | Doctor & Clinic · Medicines · Dental · Hospital · Vitamins & Supplements |
| Children & Family | School Fees · Courses & School Supplies · Childcare · Children's Needs · Supporting Parents · Supporting Relatives |
| Lifestyle | Clothing & Accessories · Personal Care [salon, barber] · Entertainment & Hobbies · Subscriptions & Streaming · Sports & Fitness · Holidays & Travel · Gadgets & Electronics |
| Financial Goals | Emergency Fund · Savings · Investments · Retirement · Pilgrimage & Big Goals [haji, umrah] |
| Giving & Social | Religious Giving [zakat, infaq, sedekah, persembahan] · Charity & Donations · Gifts · Weddings & Celebrations [kondangan] · Community Contributions [iuran RT/RW] |
| Irregular / Annual | Holiday Allowances & Gifts [THR, Lebaran] · Documents & Permits [passport, SIM] · Annual Fees · Unexpected Expenses |
| Other | Bank & Transfer Fees · Miscellaneous |
That is 14 main categories plus Other, with 73 sub-categories.
Example income categories: Salary · Business Income · Freelance & Side Income · Bonus & THR · Investment Returns · Gifts Received · Other Income.
5.4 Tips that keep a classification clear
- Purpose wins over payment timing. A yearly gym membership is Lifestyle → Sports & Fitness, even though it's paid once a year. Irregular / Annual is only for yearly or rare costs that have no better purpose category.
- Miscellaneous should stay small. If it grows, a new sub-category is probably needed.
- Users can customize. Owners of a space can rename, archive, add, and reorder categories (FR-CAT-2), so the system fits different lifestyles and businesses.
- Less detail is fine. Users can track only at the main-category level.
6. How Crest encourages the habit
| Barrier | How Crest helps |
|---|---|
| "It takes too long." | Add a transaction in 3 taps and under 10 seconds; the last-used financial account and most-used categories come first |
| "I forget." | Optional daily reminder at a time you choose; recurring transactions record themselves |
| "My money is everywhere." | Every cash wallet, bank, e-wallet, and credit card in one place |
| "I don't see the point." | Dashboard, spending by category, month-to-month trends, and budget progress show the value of every entry |
| "I missed a few days." | Log late entries with the right date; no streaks to lose, no guilt |
| "It's shared money." | Shared spaces show everyone the same picture and who added what |
| "I don't want to sign up for another service." | Open Crest and start: no email, no password, no waiting for approval |
| "I don't trust apps with my money data." | Works on your own device and sends nothing to Crest unless you connect; no ads, no data selling, cloud data stored in Indonesia, and Crest never moves money |
7. What success looks like
- People who start recording keep going: at least 40% still log a transaction in their fourth week (BO-1).
- After a month, users can answer "where did my money go?" with a real number.
- Users set budgets that match their life (BO-3), and see savings and goals move forward.
- Couples, families, and small teams use shared spaces to talk about money with facts.