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Software developer, product builder, market-notes writer

İsmail Harmanda

software, product thinking, and market literacy in the same room.

I have spent years building mobile and frontend products. More recently, @yatirimci became a public notebook about prices, data, physical assets, housing, and everyday economics. This site is the personal home between those worlds.

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Illustrated portrait of İsmail Harmanda

Public notebook

@yatirimci

Where code meets money, and data meets judgment

Stack

React Native · Next.js · Swift

Experience

10+ years building

indirimRadar

Price history

Altın Yastık

Savings tracking

Identity map

Three axes

I have spent years building mobile and frontend products. More recently, @yatirimci became a public notebook about prices, data, physical assets, housing, and everyday economics. This site is the personal home between those worlds.

01 / Software

Turning complex ideas into working products

I work across React Native, Swift, React, and Next.js, building consumer apps, operational interfaces, and high-traffic mobile experiences.

02 / Data

Reading price, history, and context together

Discounts, gold, silver, rent, and housing decisions need more than a single number. I care about history, incentives, and daily life.

03 / Product

Tools that quietly make users stronger

With products like indirimRadar and Altın Yastık, the aim is to make noisy markets easier to read, track, and act on.

@yatirimci

Writing style

On @yatirimci I publish long-form notes, practical checklists, and attempts to read the hidden structure of everyday economics.

Follow the notesLive feed

Physical assets

Do not ignore counterparty risk

The point of a physical asset is not only price, but storage, access, and the chain of trust around it.

Housing checklist

You buy a daily rhythm, not just an apartment

Noise, smell, street slope, market day, and the business downstairs are part of the true cost of a home.

Price history

A discount percentage is not enough data

To know whether a price is good, read the last 30-90 days rather than the current label alone.

Product building

Good tools reduce decision load

An app becomes durable when it helps people decide better, not merely faster.

Products

Apps I build

Products born from my own daily questions: price tracking, savings literacy, and better decision ground.

indirimRadar app artwork

Amazon Türkiye price history and deal tracking

indirimRadar

A price tracking app that reads today's price together with its history and reduces fake-discount noise.

Price historyPrice drop alertsReal discount analysis
App StoreGoogle Play
Altın Yastık app artwork

Gold price, savings, and portfolio tracking

Altın Yastık

A simple way to track gold savings, buy-sell records, profit and loss, and price movements in one place.

Live price trackingPortfolio managementDetailed charts
App StoreGoogle Play

@yatirimci

Selected X notes

A pinned tweet and selected notes from the account's main themes: price, data, physical assets, housing, and product building.

Most engaged notes

See all notes on X

Operating notes

Short principles

The thinking behind this site: technical care, market literacy, and the real cost of daily life.

I watch behavior more than labels

What something is called matters less than how it behaves over time, whether it is an asset, a product, or a person.

I ask what the beautiful thing costs to operate

A listing photo, a polished UI, or an investment thesis is never enough. Daily friction usually decides.

Data is cool, decisions remain human

Charts and price history can ground a decision, but comfort, rhythm, and risk perception still matter.