About and Methodology
Where the numbers come from, who writes the text and how far to trust each: how the site works, in the open.
- Opening Bell
- 09:30
- 16:30 TR
- Closing Bell
- 16:00
- 23:00 TR
- Pre-Market
- Regular Session
- After Hours
Who Builds It
Opening Bell is a personal project by developer Ahmet Akyapı. It is not a company, a brokerage or an investment adviser, and there is no advertiser or sponsor behind it.
Why it exists: everyone following US markets from Turkey was doing the same translation every day. Sources publish in New York time, an earnings report is due "after the close" and everyone works out what that means in Turkish time, a calculation that shifts by an hour when US daylight saving changes. The site was built to do that translation once, correctly.
Principles
No Ads
No advertising, sponsored content or paid membership.
Free
Nothing is paywalled; an account only keeps your own lists and portfolio.
Open Source
All of the code is on GitHub: you can read how any number is calculated.
No Invented Numbers
A number without a source is not printed; a measure that cannot be shown honestly is not shown.
Privacy
Page measurement is cookieless: no IP address, full referrer or browser identifier is stored, and there is no third-party analytics. If you create an account, every field kept is listed one by one in the privacy notice.
PrivacyWhere the Data Comes From
Every number on the site has a named source. The site does not invent numbers; it computes, formats and stamps what the source provides.
Sources
- AlpacaStock and fund prices, chart bars. Real-time IEX prices in session; volume, charts and extended hours from the consolidated tape (SIP), 15 minutes delayed.
- IEXReal-time prices during the session. Data provided for free by IEX.
- FinnhubCompany profiles, news, the earnings calendar, analyst ratings and IPOs.
- FREDUS macro series: inflation, employment, growth and rates.
- U.S. Treasury and CboeOfficial daily closes for Treasury yields and the VIX.
- CBRTThe USD/TRY rate, carrying the bulletin's own date.
Three Layers of Data
Every price request passes through three gates in order. No stage produces an estimate or a made-up value.
- Live ProviderThe primary source is asked first.
- If No AnswerBackup ProviderIf it does not answer, a second source is tried.
- If No AnswerLast Known ValueIf both fail, the last stored record is shown and the card's label says so.
On Screen
The stamp under every data card: the source's name, the delay and the time the data was fetched.
Source and Time Stamps
Under every data card you will find the source name and the time the data was fetched. In session prices are real-time (IEX); thinly traded symbols and extended hours are 15 minutes delayed, and the stamp says which. If a record is from yesterday the date is written out; a record that may be stale is flagged.
A percentage that cannot prove which session it describes is not shown as "today". A measure that cannot be shown honestly is not shown at all: the card stays empty or the measure is removed.
Times in Turkish Time
On the Turkish site Istanbul time comes first with New York time beside it; in English the order flips. No clock time is hard-coded; every time is computed for that day's date, so it stays right when US daylight saving changes. The session hours at the top were computed for today's date too.
How the Writing Is Produced
The daily brief, Close-Up stories, earnings analyses and technical analyses are written by scheduled routines running Claude, Anthropic's AI model. We do not hide this: there is no human byline on them because no human writes them.
The Site Computes
Moving averages, RSI, MACD and pivot levels are computed from the site's own price data and handed to the routine.
The Routine Writes
The scheduled routine writes only the commentary; it produces no numbers.
The Write Layer Checks
The format is validated; a price not proven to belong to that session cannot enter the text.
The Owner Corrects
Published text is read and corrected from the admin panel, and its previous version is kept.
Publishing Rhythm
- Every Day
- Brief
- Two a Day
- Close-Up Stories
- The Day After
- Earnings Analyses
- Three per Trading Day
- Technical Analyses
- Mondays
- Weekly Brief
Guide articles live in the code itself, and every change to them goes through review.
Add It to Your Site
You can put the opening countdown or this week's earnings on your own site. Copy the code and paste it into your page; for a dark background set the theme value in the address to koyu.
Opening Countdown
<iframe src="https://aciliszili.com/en/gomulu/geri-sayim?tema=acik" title="Opening Countdown" width="100%" height="240" style="border:0;max-width:480px" loading="lazy"></iframe>This Week's Earnings
<iframe src="https://aciliszili.com/en/gomulu/bilancolar?tema=acik" title="This Week's Earnings" width="100%" height="524" style="border:0;max-width:480px" loading="lazy"></iframe>Not Investment Advice
No number, view or article on this site is a recommendation to buy or sell. The Buy, Hold and Sell views in technical analysis are the output of a method; they know nothing about your savings, risk appetite or tax situation. Talk to a licensed adviser before making a decision.