How it works
What a resolver is, and whether you need one
A resolver turns the identifier in a code into the address of that product's data, and sends the request there. It is the step between the scan and the answer.
A resolver is the service that turns the identifier in a code into the web address of that product's data. It then sends the request to that address. That middle step lets the address change after you print the code.
You probably do not have to run one. The company that places your product on the European market carries the passport duty. That company is usually your European importer.
The middle step saves you a reprint. If you put one fixed web address in the code, a change of website or of service provider breaks every code you printed. You cannot recall a swing tag from a shop in Hamburg.
Five steps run between the scan and the answer
| Step | What happens |
|---|---|
| 1 | A person or a scanner reads the code on the product |
| 2 | The code carries an identifier for that one product |
| 3 | The resolver finds where the data for that identifier lives |
| 4 | The request goes to that place |
| 5 | The data comes back, as a page or as structured data |
Warning: this site has found no verified legal rule for steps 3 and 4. So do not buy a resolver to meet a legal requirement. Buy one when a customer asks you to serve product data from a scanned code. Keep that contract short enough to change.
Steps 3 and 4 are the resolver. The last step can give two answers from the same address. A person gets a page, and a machine gets structured data. See content negotiation and how a passport works.
The code is printed once, and the address can move later
A code on a product is permanent in practice. You print it on the swing tag of a merino jumper or on the label of an e-bike battery. The product goes into a container, and the code stays as it is for the life of that product.
European law leaves the passport data with a company. Three verified rules decide who holds that data, and for how long. Two of them come from the Ecodesign for Sustainable Products Regulation (ESPR).
| Rule | What it says |
|---|---|
| ESPR, Article 10(c) | The passport is "stored by the economic operator responsible for its creation or by digital product passport service providers" |
| ESPR, recital 41 | The passport needs "a decentralised data system" |
| Battery regulation (EU) 2023/1542, Article 78(e) | The battery passport stays available after the responsible operator ceases to exist |
Read those three rows together. The identifier belongs to the product. The address belongs to the company that holds the data at that time. A resolver keeps the two apart, so one can change without the other.
That last sentence is a conclusion from the rules above, none of which states it.
The data sits with a company, so something must route the request
Warning: ESPR creates no passport duty for a product until the Commission adopts a delegated act for that product group. It has adopted none, as at August 2026. See what a delegated act is.
ESPR is Regulation (EU) 2024/1781. It has been in force since 18 July 2024. Article 10(c) and recital 41 keep the passport data with a company. So there is no central European store of product data, and no single address to print in a code.
The registry stores identifiers, not your product data
People confuse the resolver with the EU registry, but the two do different jobs.
Article 13(1) of ESPR reads:
By 19 July 2026, the Commission shall set up a digital registry (the 'registry') which stores in a secure manner at least the unique identifiers.
That date is the statutory deadline. The Commission launched the registry, with a testing environment, on 20 July 2026. It has been operational since then.
The registry works as a directory. It holds the unique identifiers, and it gives back a registration identifier. The fibre content of your jumper stays with the operator, or with the service provider that the operator pays. Article 10(c) says so.
Article 13(5) states that the registry's communication "shall not be deemed to be proof of compliance with this Regulation or other Union law". A registration identifier is not a compliance certificate.
Implementing Regulation (EU) 2026/1778 governs the registry, and this site has now read the full act. Article 8(9) lists what the registry keeps. Where relevant, it keeps the unique identifiers, the commodity code, a reference to a passport service provider, and information about the registrant. See the EU registry.
No verified rule says what a resolver must do
ESPR Annex III names the ISO/IEC 15459 series. It names parts 1 to 6. The data carrier and the unique product identifier must comply with that series, where it is relevant for the product. Article 10(1)(c) makes this an interim rule. It runs until the Commission publishes the references of harmonised standards.
The regulation names no vendor scheme. A search of the full text returns no hit for GS1, for Digital Link, for IEC 61406 or for the digital object identifier (DOI). So no supplier can cite ESPR for a claim about the address format in your code.
Implementing Decision (EU) 2026/1736 cites six European standards. The table below gives the title of each one.
| Standard | Official title |
|---|---|
| EN 18216 | Digital product passport - Data exchange protocols |
| EN 18219 | Digital product passport - Unique identifiers |
| EN 18220 | Digital product passport - Data carriers |
| EN 18221 | Digital product passport - Data storage, archiving, and persistence |
| EN 18222 | Digital Product Passport - Application Programming Interfaces (APIs) for product passport lifecycle management and searchability |
| EN 18223 | Digital Product Passport - System interoperability |
Every one of the six is paywalled, and this site has read none of them. So this page states no requirement and no protocol from any of them.
The set has a gap in the numbering. There is no EN 18217 and no EN 18218. Never accept the set written as a range. See the six standards.
A battery passport can be replaced, and it ends after recycling
The battery regulation, Regulation (EU) 2023/1542, is in force. The passport duty applies from 18 February 2027. Three categories need a battery passport:
- each light means of transport (LMT) battery, such as an e-bike battery
- each industrial battery with a capacity greater than 2 kilowatt hours
- each electric vehicle battery
Warning: Article 78 governs the battery passport only, so it sets no rule for the passport of any other product. See batteries.
| Article | The rule |
|---|---|
| Article 77(3) | Each battery carries a unique identifier |
| Article 77(7) | A repurposed battery needs a new passport |
| Article 77(8) | The passport ceases to exist after the battery is recycled |
| Article 78(e) | The passport stays available after the responsible operator ceases to exist, or ceases its activity in the Union |
Read those four rows together. The passport belongs to a single battery. It does not belong to a model or to a batch. A repurposed battery gets a new passport. After recycling, the passport stops.
A resolver can point at the record that exists at the time of the scan. A fixed address printed on the cell cannot. That last point is this site's reasoning.
Who places the product on the market decides if you need one
If your company has no office in the Union, you are usually not the operator that carries the duty. The importer is. See who is the economic operator and what a passport service provider does.
Warning: one industry paper disagrees. The PARSEC, CIRPASS-2 and BORDERLINK projects published it on 31 March 2026. It states that a non-EU manufacturer stays a duty-holder, whatever its place of establishment. That paper is not the legal text. Agree the data duties with your importer in writing. See agreeing data duties.
No rule requires the three steps below today, and each one is still your work.
- Give each export product an identifier that is unique.
- Never reassign that identifier.
- Make sure you can correct the data behind it, without a reprint.
No New Zealand government guidance explains how to build, host or resolve a passport. The Ministry of Foreign Affairs and Trade market report of October 2025 stops at data tracking and reporting systems. See what New Zealand agencies have said.
Five questions to ask before you pay for a resolver
- Which company places our product on the European market?
- If we change provider, does the printed code still work?
- Can you correct the data without a new identifier and a reprint?
- Which of the six cited standards does the service implement, by number?
- Which delegated act covers our product group?
Question five has one answer today for every product group: none. A supplier who answers it with a year is quoting the year the Commission expects to adopt the rule. See how to read the timeline.
OwlQR, a New Zealand company that publishes this site, runs a resolver service. Ask that company the five questions above. Ask every other supplier the same five questions.
Open-source resolvers exist too, and the OpenDPP catalogue lists some of them.