Tell you not to buy
If the used copy costs €19.88 and the new one €19.90, Pecia says so. A site that tells you when it's not worth it is the only one you can believe when it says it is.
About Pecia
That's the gap. The mechanism is simple: watch it for you, in any edition, shipping included, and tell you the day it crosses your price.
You hear about a book on a podcast, jot it down somewhere and lose it. When you remember, you don't know where to get it cheap without checking five websites by hand. Pecia started as exactly that: a fix to stop losing books.
And looking at the category, something odder showed up. Goodreads links to Amazon because it's owned by Amazon. StoryGraph links to new copies. The whole category treats buying as an affiliate link at the bottom of the page — never as data that sorts, filters and triggers alerts. Nobody publishes the second-hand price.
Engine first, interface second. Resolve a title to all its Spanish editions, look each one up in second-hand bookshops, always add shipping, drop foreign editions that share the title, and tell “doesn't exist” apart from “no used copy”.
None of that is glamorous and every step broke at least once. The French edition of Fahrenheit 451 won at €5.90 until we filtered by language. Booksellers catalog “CHICO PERDIDO, EL”, so the articles had to go before it could be found.
A tool that earns when you buy has a conflict of interest. These are the lines, written before any money is involved.
If the used copy costs €19.88 and the new one €19.90, Pecia says so. A site that tells you when it's not worth it is the only one you can believe when it says it is.
Some links may earn a few cents, and they'll be marked as such on the book page itself, not in the footer. They never change which offer comes first: total price sorts, always.
No ads and no selling data. From your Kindle we read the title and your progress, nothing else — the book never leaves your device. Export everything or delete your account whenever you like.
Spain's fixed book price law allows at most 5% off new books, so there's nothing to compare: the only place prices move is used and out-of-print books.
And it happens to line up with the rest: printing a copy of about 300 pages emits around 1.2 kg of CO₂. One that's already printed emits nothing, it just changes shelves.
We didn't invent reusing books. In the 13th century, universities split a book into numbered quires —the peciae— and rented them out one at a time, so those who couldn't buy it could copy it. Hence the name.
Pecia is built by Rumbo Labs, an independent software studio based in Barcelona making small, sharp products under one roof. No venture capital, funded by its own products. These are its siblings:
One person, part-time, from Barcelona. Pecia is built in the open: what works, what doesn't yet, and the numbers behind each decision. If you want to suggest something —a bookshop that should be here, an integration, a bug— or just give us feedback, write.