hereby app lets you leave a line of text readable only on the spot

What can you do with hereby?

You can drop a note on a street, in a park or at a pier. Version 1.1, released on 31 October, added "Birine bırak" (leave it for someone). You write a line for one person and share a link, but the link alone is not enough: the recipient has to go to the spot to read it. Other uses include time capsules, notes to your future self, or a trace about a stray animal.

The app also has "İz Yolları" (trace routes), poetry walks with lines from Doğan's books in Kadıköy, Beşiktaş and the Bosphorus area. Right now there are three walks with 13 stops in total and nearly 40 author traces. Walk from Haydarpaşa Station to Moda shore and the verses appear along the way, each one only when you arrive.

A longer project, writtenby., would let users write one line a day from where they are. Doğan plans to collect those lines in a printed book about Istanbul at the end of 2027.

Is hereby private and free?

It is free, with no ads, subscriptions or commission. It asks for no name, email or phone number. Traces show an area of about 150 metres rather than the exact point, and leaving traces near homes and schools is not allowed. Data is stored within the European Union. There is no read counter, and Doğan says he cannot see that data either.

The first version took about two weeks. It uses SwiftUI, MapKit, Supabase, PostgreSQL and PostGIS for location queries. It supports 30 languages, all adapted by Doğan, and has no outside funding. An Android version and new poetry walks in more Istanbul districts and campuses are planned. Possible income could come from the printed book and custom walks for schools and cultural institutions.