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Case study · Own product

Manual logging, a rules engine that learns recurring spending, monthly budgets and goals, and a shelf of closed monthly chapters. Designed and built end to end.

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Role
Product design and development
Platforms
iOS, Android and web
Users
20 active in beta
Company
Bianki Inc
TodayDec 14 · Chapter 5
McMack says
Morning, Mira. 23-day streak. Dec is shaping up 14% better than Nov.
· 13 rules running   · 4 entries waiting on you   · Chapter 5 in progress
Saved · Dec
$1,520
+$380 vs Nov
Spent · Dec
$3,600
of $4,150 budget
Streak
23 days
Log one thing today.
Net worth
$16,356
+$1,240 this month
In · Out
Last 5 months
IncomeSpend
Aug
Sep
Oct
Nov
Dec
Recent
Activity
Tartine Bakery
PendingDec 14 · Cardinal
−$16.00
Ferry Plaza Mkt
Needs categoryDec 13 · Cardinal
−$42.00
Aesop
Needs categoryDec 12 · Cardinal
−$38.00
Whole Foods
Dec 11 · Cardinal· rule
−$82.00
You've saved more in December than three of the last five months.You've saved more in December than three of the last five months.
01The rules engine
Teach McMack once.He catches forever.

You log Whole Foods on a Saturday. McMack leans over and asks once: “Want me to catch this every week?” Say yes, and from then on every Whole Foods entry lands in Groceries on its own.

14
rules in the demo
92
caught this month
0
passwords stored
McMack's rules13 running · 92 caught
Match
Category
Cadence
Caught
On
Acme Payroll
Income
biweekly
8×
Spotify
Subscriptions
monthly
4×
Netflix
Subscriptions
monthly
4×
Whole Foods
Groceries
weekly
22×
Trader Joe's
Groceries
weekly
14×
Apt 4B Rent
Rent
monthly
5×
03Categories & budgets
December budgets9 pockets · $4,150
Groceries$484 / $500
Rent$1850 / $1850
Transport$156 / $200
Dining$320 / $400
Subscriptions$247 / $300
Twelve pockets.No yelling.

Set a monthly target on any of them. When you cross it, the bar turns coral. We don't ping, freeze, or shame you. The number is the number; you decide what to do with it.

06The bound book
Each month becomes a chapter.

On the last day of every month, you close the book together. We seal it, summarize it, and set it on the shelf.

2025
AUG
Lvl 1
$640
★ CLOSED ★
2025
SEP
Lvl 2
$980
★ CLOSED ★
2025
OCT
Lvl 3
$1,140
★ CLOSED ★
2025
NOV
Lvl 4
$1,140
★ CLOSED ★
2025
DEC
Lvl 5
in progress
· OPEN ·
Whole Foods again? Groceries. Got it.Whole Foods again? Groceries. Got it.

Today, the rules engine, budgets and the chapter shelf, on a loop

01

Problem

Most money apps are dashboards you check once and forget. Biankbook is built to be read: a short note each morning, rules that do the sorting, and a month that closes like a chapter.

02

What I built

Manual logging, a rules engine that learns recurring spending, monthly budgets and goals, and a shelf of closed monthly chapters, with McMack, a pixel companion who comments as you go.

03

Result

20Active users in beta

Across iOS, Android and the web.

04

Stack and timeframe

Stack
Next.js, tRPC, PostgreSQL, Drizzle, Redis, GSAP
Platforms
iOS, Android and web
05

My role

Product design and development, end to end. Biankbook is my own product, under Bianki Inc.

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