---
title: What link types does a GS1 Digital Link resolver support, and how does the default link work?
description: All GS1 Digital Link link types in one table, how the resolver’s default link works, and the IMDE packagingInfo link type for PPWR packaging dossiers.
---

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# What link types does a GS1 Digital Link resolver support, and how does the default link work?

## An overview of all GS1 link types, how a resolver chooses the default link, and how the IMDE link type imde:packagingInfo gives access to packaging dossiers for PPWR compliance.

**Summary:** A GS1 Digital Link (for example a QR code on a product) is resolved by a GS1-Conformant Resolver, which sends the user or system to the right information. Each link stored in the resolver has a *link type* that says what the target is: a product page, instructions, a Digital Product Passport, and so on. This article explains what link types are, lists all link types currently defined by GS1, explains how the default link works, and describes the IMDE link type `imde:packagingInfo` for packaging dossiers under the PPWR.

*Based on the GS1-Conformant Resolver Standard release 1.2.1 (ratified August 2026), the GS1 Web Vocabulary, and the IMDE Vocabulary (imde:packagingInfo, created 14 October 2026).*

### 1. What is a link type?

A resolver can hold many links for one product: a product page, a manual, a recall notice, a Digital Product Passport. The **link type** (formally the *link relation type*) says what kind of information a link leads to, so apps and systems can pick the right one without asking the user.

- **Every link has three mandatory attributes:** the target URL, the link type and a human-readable title. Language, media type and context are optional extras that help choose between similar links.
- **Link types come from a shared vocabulary.** GS1 defines them in the GS1 Web Vocabulary. They are written in a short form such as `gs1:pip`, where `gs1:` stands for `https://ref.gs1.org/voc/`, so `gs1:pip` means `https://ref.gs1.org/voc/pip`.
- **One link can have several types.** A product page that also shows nutrition and allergens can be typed `gs1:pip`, `gs1:nutritionalInfo` and `gs1:allergenInfo`.
- **One type can have several links.** A product may link to several certificates or social media channels of the same type.
- **Other vocabularies can extend the list.** A resolver must recognise all `gs1:` link types and may support other namespaces, such as `imde:` for packaging (section 5).

### 2. Supported link types

The GS1 Web Vocabulary currently defines 60 link types: 59 stable and 1 deprecated. The IMDE extension is listed at the bottom of the table.

| Group | Link type | Points to |
| --- | --- | --- |
| **Resolver control** | `gs1:defaultLink` | The single default redirect (resolver use only) |
|  | `gs1:defaultLinkMulti` | Default variants chosen via request headers (resolver use only) |
|  | `gs1:handledBy` | Pattern-based hand-off to another resolver (resolver use only) |
| **Product information** | `gs1:pip` | Product information page |
|  | `gs1:masterData` | Structured master data, typically B2B |
|  | `gs1:dpp` | Digital Product Passport |
|  | `gs1:smartLabel` | SmartLabel page |
|  | `gs1:whatsInTheBox` | Contents of the pack |
|  | `gs1:backgroundInfo` | Creative or technical background of the item |
|  | `gs1:relatedImage` | Related image |
|  | `gs1:relatedVideo` | Related video |
| **Food** | `gs1:allergenInfo` | Allergen information |
|  | `gs1:ingredientsInfo` | Ingredients |
|  | `gs1:nutritionalInfo` | Nutritional facts |
|  | `gs1:recipeInfo` | Recipes |
|  | `gs1:menuInfo` | Menu or list of offerings |
| **Use and support** | `gs1:instructions` | Instructions (not for regulated healthcare content) |
|  | `gs1:quickStartGuide` | Quick start guide |
|  | `gs1:tutorial` | Tutorials, how-to videos |
|  | `gs1:faqs` | Frequently asked questions |
|  | `gs1:support` | Helpdesk or support channel |
|  | `gs1:serviceInfo` | Service and maintenance instructions |
|  | `gs1:activityIdeas` | Ideas for using the product |
|  | `gs1:purchaseSuppliesOrAccessories` | Where to buy supplies or accessories |
|  | `gs1:registerProduct` | Product or warranty registration |
|  | `gs1:reportFound` | Reporting a found item |
| **Safety and compliance** | `gs1:safetyInfo` | Safety information |
|  | `gs1:consumerHandlingStorageInfo` | Safe handling and storage |
|  | `gs1:recallStatus` | Recall status, typically an API |
|  | `gs1:certificationInfo` | Certification information |
|  | `gs1:sustainabilityInfo` | Sustainability and recycling (consumer-facing) |
|  | `gs1:productSustainabilityInfo` | **Deprecated**, use `gs1:sustainabilityInfo` |
| **Traceability and verification** | `gs1:traceability` | Traceability, track and trace |
|  | `gs1:epcisRepository` | EPCIS repository of event data |
|  | `gs1:verificationService` | Lightweight Messaging verification service |
|  | `gs1:jws` | JSON Web Signature |
|  | `gs1:registryEntry` | Entry in an official register |
| **Healthcare** | `gs1:epil` | Electronic patient information leaflet (validated healthcare only) |
|  | `gs1:smpc` | Summary of Product Characteristics (validated healthcare only) |
|  | `gs1:eifu` | Electronic instructions for use, medical devices (validated healthcare only) |
|  | `gs1:brandHomepagePatient` | Brand information for patients |
|  | `gs1:brandHomepageClinical` | Brand information for clinical professionals |
| **Commerce and engagement** | `gs1:hasRetailers` | List of retailers |
|  | `gs1:promotion` | Promotion |
|  | `gs1:loyaltyProgram` | Loyalty programme |
|  | `gs1:review` | Reviews |
|  | `gs1:leaveReview` | Where to add a review |
|  | `gs1:subscribe` | Subscription form |
|  | `gs1:socialMedia` | Social media channel |
|  | `gs1:appDownload` | Related mobile app |
|  | `gs1:paymentLink` | Payment details or payment page |
|  | `gs1:userAgreement` | Agreement or waiver to sign |
| **Organisation and location** | `gs1:homepage` | Organisation or brand homepage |
|  | `gs1:careersInfo` | Jobs and careers |
|  | `gs1:statisticInfo` | Statistics about an organisation or location |
|  | `gs1:locationInfo` | Map, directions, location details |
|  | `gs1:logisticsInfo` | B2B logistics information for a location |
|  | `gs1:openingHoursInfo` | Opening hours |
|  | `gs1:eventsInfo` | Event details |
|  | `gs1:scheduleTime` | Scheduling, appointments, reservations |
| **Packaging (IMDE extension)** | `imde:packagingInfo` | Packaging dossier of the Packaging System: EU Declarations of Conformity, technical documentation and packaging composition, as JSON (B2B, PPWR and EPR) |

*The grouping is for readability; GS1 publishes the list alphabetically.*

### 3. How the default link works

There is **no fixed default link type** in the GS1 resolver standard. The default is set **per identified entity**, not globally.

- **Exactly one default per entity.** Each identified entity (for example a GTIN) has exactly one default link, typed `gs1:defaultLink`. The party that registers the links decides which one it is.
- **A marker, not a content type.** The default link must also carry a descriptive link type. A product page used as default is typed both `gs1:defaultLink` and `gs1:pip`. In practice `gs1:pip` is the most common default, but the standard does not prescribe it.
- **No extra attributes.** The default link has a title, but no language, media type or context.
- **Inheritance down the hierarchy.** The default may be set at primary key level only (for example the GTIN). A more granular URI (CPV, batch/lot, serial number) uses the default at its own level or the nearest level above it.
- **Default variants.** Optional `gs1:defaultLinkMulti` links let the resolver choose a better default based on the HTTP request headers, mainly the user's language.
- **Linkset as default.** A resolver may allow the default to be set to the full list of links instead of a redirect. The resolver declares this in its description file (`linkTypeDefaultCanBeLinkset`).

### 4. Requesting a link type

| Request | Resolver response |
| --- | --- |
| No `linkType` parameter | Redirect to the default link (or the best matching `gs1:defaultLinkMulti` variant) |
| `?linkType=gs1:nutritionalInfo` and the link exists | Redirect to that link |
| `?linkType=...` and several links match equally | 300 Multiple Choices with the list of matching links |
| `?linkType=...` and the link does not exist | 404 Not Found (optionally with the full list of links). Older resolvers based on Digital Link 1.1 redirected to the default instead. |
| `?linkType=linkset` or header `Accept: application/linkset+json` | 200 |

### 5. The IMDE link type imde:packagingInfo

`imde:packagingInfo` is defined in the IMDE Vocabulary (Interoperable Modular Data Exchange) and is designed to sit next to the GS1 link types. It points to the packaging dossier of an item, for systems that need to assess, store or report on that packaging under the PPWR (Regulation (EU) 2025/40) and for EPR reporting.

| **Full URI** | `https://imde.io/voc/packagingInfo` |
| --- | --- |
| **Compact form** | `imde:packagingInfo` (prefix `imde:` = `https://imde.io/voc/`) |
| **Label** | Packaging information |
| **Status** | Stable (created 14 October 2026) |
| **Target media type** | `application/json` |
| **Target profile** | IMDE Packaging System data container (JSON Schema): `https://imde.io/schema/packaging-system` |
| **Can start from** | 150 |

#### The Packaging Digital Link

One Packaging System is often used by many sales units and transport units, and in private label several Manufacturers each sign their own EU Declaration of Conformity for it. The Packaging Digital Link keeps **one dossier per Packaging System**; every party that needs it stores **one link** instead of copies of the files. A change is published once, at the link.

The link uses ANSI MH10.8.2 Data Identifier `31B` for the Packaging System, following ISO/IEC 18975:

```
https://{resolver domain}/31B/{Packaging System identifier} 
```

```
Example: https://prodigi.link/31B/VTA-MPLA-PS-3YJHUG2A
```

The Packaging Digital Link does not replace the GS1 Digital Link of the product. The GS1 Digital Link of a sales or transport unit (`/01/{GTIN}`) carries an `imde:packagingInfo` link to the Packaging Digital Link of each Packaging System it runs on. The GTIN link points to the Packaging Digital Link, not directly to the dossier file, so when the dossier moves only the Packaging System link changes.

#### What the dossier contains

- **EU Declarations of Conformity:** one per Manufacturer, for the Packaging System and the sales and transport units that run on it.
- **Technical documentation:** the proof of conformity with evidence files, such as test reports, supplier declarations and calculations.
- **Packaging composition:** packaging elements, materials and composite materials, with form-related attributes (packaging type, dimensions, weight) and material-related attributes (material type, recycled content). Uses the PPWR categories: sales, grouped, transport and e-commerce packaging.

#### When to use another link type

- Consumer-facing sorting and recycling guidance: `gs1:sustainabilityInfo`
- General product master data: `gs1:masterData`
- A single certificate: `gs1:certificationInfo`

#### Examples

Request the packaging dossier of a Packaging System:

```
GET https://prodigi.link/31B/VTA-MPLA-PS-3YJHUG2A?linkType=imde:packagingInfo  
```

```
HTTP/1.1 307 Temporary Redirect Location: https://{dossier host}/packaging-system/VTA-MPLA-PS-3YJHUG2A.json
```

Start from a GTIN:

```
GET https://prodigi.link/01/{GTIN}?linkType=imde:packagingInfo  
```

```
HTTP/1.1 307 Temporary Redirect Location: https://prodigi.link/31B/VTA-MPLA-PS-3YJHUG2A?linkType=imde:packagingInfo
```

Request all links (linkset):

```
GET https://prodigi.link/31B/VTA-MPLA-PS-3YJHUG2A?linkType=linkset 
```

```
Accept: application/linkset+json  {   "linkset": [{     "anchor": "https://prodigi.link/31B/VTA-MPLA-PS-3YJHUG2A",     "https://imde.io/voc/packagingInfo": [{       "href": "https://{dossier host}/packaging-system/VTA-MPLA-PS-3YJHUG2A.json",       "type": "application/json",       "profile": "https://imde.io/schema/packaging-system",       "title": "Packaging System dossier"     }]   }] }
```

### Resolver requirements for imde:packagingInfo

- Conform to the GS1 Digital Link and GS1-Conformant Resolver standards and ISO/IEC 18975.
- Accept ANSI Data Identifiers (such as `31B`) as path segments, next to GS1 Application Identifiers (such as `01`).
- Recognise the `imde:` namespace, so that `linkType=imde:packagingInfo` and the full URI are treated as the same link type. Declare the namespace in the resolver description file (`supportedLinkType`).
- In linksets and HTTP Link headers, always write the full URI `https://imde.io/voc/packagingInfo`; the compact form is for the `linkType` query parameter.
- Return linksets as `application/linkset+json` (RFC 9264) and redirect with HTTP 307 to the requested target.

**Note:** the IMDE specification says an unknown link type falls back to the default link. The GS1-Conformant Resolver Standard (1.0 and later) requires a 404 Not Found in that case. Check which behaviour your resolver follows.

If GS1 publishes an equivalent link type, IMDE will declare `imde:packagingInfo` equivalent to it and the URI will keep resolving.

```
6. Sources
```

- [GS1-Conformant Resolver Standard, release 1.2.1 (August 2026)](https://ref.gs1.org/standards/resolver/1.2.1/GS1_Conformant_Resolver_standard_i1.2.1-r-2026-08-07)
- [GS1 Web Vocabulary: all link types](https://ref.gs1.org/voc/?show=linktypes) ([JSON](https://ref.gs1.org/voc/data/linktypes))
- [IMDE: Packaging Digital Link](https://imde.io/index.php?title=Packaging_Digital_Link_-_DT)
- [IMDE Vocabulary: imde:packagingInfo](https://imde.io/voc/packagingInfo)

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