Take the “capacity” field of a battery. Your forwarder calls it one thing in its paperwork, the recycler another, and the authority has a third name for it on its form. All three mean the same, and all three have to be sure they mean the same. In 2034 an inspector reads your passport from 2026 and has to know, without asking, what your value meant back then.
That is the whole task behind the question of which terms a Digital Product Passport carries. It sounds like detail work, but it decides whether anyone can still read your data in ten years.
This article explains which three dictionaries a passport uses, why every term needs a fixed address, and why you notice none of it in daily work.
The passport invents no new language
A product passport brings three existing dictionaries together. Each describes one part of the product world, and none is enough on its own.
The first describes what happened to the product: shipped, repaired, recalled, recycled. It comes from GS1 and is called EPCIS, the same standard logistics has used for years to record supply chains. Every step gets a name and a state, and the steps add up to a log any machine can read: when a batch was shipped, when it was recalled, when it was recycled.
The second describes what the product is: material, recycled content, CO2 footprint, repairability. It is called OpenEPCIS DPP Core and is published openly at ref.openepcis.io.
The third describes what your regulation requires. Each product group brings its own technical vocabulary:
- batteries (Regulation 2023/1542): over 200 properties, from cell chemistry through recycled-content shares for lithium, cobalt and nickel to charge cycles and the battery’s state of health
- textiles: fibre composition, dyes, microplastic risk class, washing symbols, recyclability
- electronics: repair index, component types, replaceability of individual components
- plus dictionaries of their own for deforestation, detergents, packaging and construction products
So a passport switches its technical vocabulary with the product group and still stays on the same frame. Which regulation and which mandatory data that means per industry is in the industries reference.
Every term has a fixed address
So that three dictionaries do not turn into a muddle, the passport carries an index that points every term to its definition. Every term has exactly one home in it: an address on the web where anyone can look up what it means.
This is more than tidiness. A passport has to stay verifiable for ten years and longer. If an authority reads a passport issued in 2026 in the year 2034, the recycled content must still mean exactly what it means today. That only holds if the address still points to the same definition years later, for the platform, the archive, the auditor and the authority alike.
Why your own field names are an island
Whoever invents their own field names instead builds an island. The authority, the recycler and a third party’s verification tool have to understand what is in your passport without asking. That only works when the terms come from dictionaries those readers already know.
Own names also make a change of provider expensive, because the meaning then sits in the old system instead of in the data. That is exactly why Transpareo sticks strictly to the three dictionaries instead of inventing its own.
Two rules that prevent errors
Share values are always decimal numbers between 0 and 1, so 0.85 rather than 85 per cent. That one rule removes a whole class of import errors.
And every piece of information carries an access level: public, for authorised readers, or restricted. That is how the same passport delivers different views to end customers, partners and authorities.
40 languages in one field
A text field carries its language variants in one compact form, {"de": "Wasser", "en": "Water"}, instead of being repeated per language. That keeps the data small, and a reader gets the passport in their browser language and falls back to English where a language is missing. 40 languages, including all 24 official EU languages, are covered this way without special logic.
What you notice of all this
Nothing, and that is on purpose. You maintain products, components and materials in your own words, through the interface, by import or via the API. The platform speaks the three dictionaries underneath and applies the right technical vocabulary for each product group without you rebuilding the data model.
Which dictionaries a platform speaks matters when you choose one, not in daily work afterwards. Three questions are enough: does it use the established dictionaries or one of its own that only it understands? Can it apply the right technical vocabulary per product group? And does every term sit at an address that will still hold in ten years?
Three times yes, and your passport stays readable: today, across a change of provider, and beyond the statutory retention period.
Questions on this article
Do we have to know these dictionaries to publish a passport?
No. The dictionaries decide what the fields are called in the published data, not what you type in. You maintain products, components and materials through the interface, by import or via the API, and the passport carries the standard terms underneath. Which dictionaries a platform speaks matters when you choose one, not every day afterwards.
Which dictionary covers which part of the passport?
There are three. What happened to the product follows GS1 EPCIS 2.0, the same standard that has mapped logistics supply chains for years, with a business step and a state per event. What the product is, so material composition, recycled content, CO2 footprint and repairability, follows the OpenEPCIS DPP Core. Above that sits the technical vocabulary each EU regulation requires. A product name still comes from schema.org, the dictionary search engines read.
What is wrong with our own field names?
They build an island. An authority, a recycler or a third party’s verification tool has to understand what is in your passport without asking you first, and that only works when the terms come from dictionaries those readers already know. Own names also make a change of provider expensive, because the meaning then sits in your old system rather than in the data.
Does the vocabulary change per product group?
Yes, and the platform has to carry that without you rebuilding the data model. Batteries alone bring over 200 properties, from cell chemistry through recycled-content shares for lithium, cobalt and nickel to charge cycles and the battery’s state of health. Textiles require fibre composition, dyes, a microplastic risk class, washing symbols and recyclability; electronics a repair index, component types and replaceability. Deforestation, detergents, packaging and construction products each add their own.
Why do fixed addresses matter so much?
Because a passport has to stay verifiable for ten years and longer. If an authority reads a passport issued in 2026 in the year 2034, the recycled content must still mean exactly what it means today, and that only holds when the definition sits at an address which points to the same thing years later. Fixed addresses are what let the platform, the archive, an auditor and an authority all point at one definition.
How are shares and units written?
Share values are always decimal numbers between 0 and 1, so 0.85 rather than 85 per cent. That one rule removes a whole class of import errors. Every piece of information also carries an access level, public, authorised or restricted, and that is how the same passport delivers different views to end customers, partners and authorities.
Do we have to translate the passport ourselves?
No. A text field carries its language variants in one compact form instead of being repeated per language, so 40 languages, including all 24 official EU languages, are covered without special logic. A reader gets the passport in their browser language and falls back to English where a language is missing. How that translation is produced is in 40 languages automatically.
Are these standards actually mandatory?
The harmonised European DPP standards are not an obligation. Whoever meets them counts as compliant and does not have to prove it. Six of them were cited in the EU Official Journal on 15 July 2026 by Implementing Decision (EU) 2026/1736. You may meet the requirements another way, but then you carry the burden of proof. More in standard by standard.
