DPMA Connect Plus Go Client

A Go client library for the German Patent and Trademark Office (DPMA) Connect Plus REST API.

Getting Started

Authentication

DPMA Connect Plus is a paid service requiring authentication:

Service Details: https://www.dpma.de/recherche/datenabgabe/dpmaconnect/index.html
Access: Contact DPMA to obtain credentials
Authentication Method: HTTP Basic Authentication

Installation

go get github.com/patent-dev/dpma-connect-plus

Quick Start

package main

import (
    "context"
    "fmt"
    "log"

    dpma "github.com/patent-dev/dpma-connect-plus"
)

func main() {
    client, err := dpma.NewClient(&dpma.Config{
        Username: "your-dpma-username",
        Password: "your-dpma-password",
    })
    if err != nil {
        log.Fatal(err)
    }

    ctx := context.Background()

    // Get service version
    version, err := client.GetVersion(ctx, dpma.ServicePatent)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("Version: %s\n", version)

    // Validate query before sending (optional but recommended)
    if err := dpma.ValidatePatentQuery("TI=Elektrofahrzeug"); err != nil {
        log.Fatal(err)
    }

    // Search patents (uses DPMAregister expert search syntax)
    results, err := client.SearchPatents(ctx, "TI=Elektrofahrzeug")
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("Results: %d bytes\n", len(results))
}

API Methods

All methods accept context.Context for timeout and cancellation support.

Common Operations

// Get service version
GetVersion(ctx, service string) (string, error)

Use the service constants: dpma.ServicePatent, dpma.ServiceDesign, dpma.ServiceTrademark.

Query Validation

// Validate a query against service-specific field codes (returns nil or error)
ValidatePatentQuery(query string) error
ValidateDesignQuery(query string) error
ValidateTrademarkQuery(query string) error

For advanced usage (tokenization, field inspection), use the query sub-package directly.

Patent Service

// Search patents and utility models
SearchPatents(ctx, query string) ([]byte, error)

// Get patent info by registered number
GetPatentInfo(ctx, registeredNumber string) ([]byte, error)

// Get searchable full text for a document
GetSearchableFullText(ctx, documentID string) ([]byte, error)

// Download single patent publication PDF
GetPatentPublicationPDF(ctx, documentID string) ([]byte, error)

// Weekly bulk downloads (XML)
GetDisclosureDocumentsXML(ctx, year, week int) ([]byte, error)
GetPatentSpecificationsXML(ctx, year, week int) ([]byte, error)
GetUtilityModelsXML(ctx, year, week int) ([]byte, error)
GetPublicationDataXML(ctx, year, week int) ([]byte, error)
GetApplicantCitationsXML(ctx, year, week int) ([]byte, error)
GetEuropeanPatentSpecificationsXML(ctx, year, week int) ([]byte, error)

// Weekly bulk downloads (PDF)
GetDisclosureDocumentsPDF(ctx, year, week int) ([]byte, error)
GetPatentSpecificationsPDF(ctx, year, week int) ([]byte, error)
GetEuropeanPatentSpecificationsPDF(ctx, year, week int) ([]byte, error)
GetUtilityModelsPDF(ctx, year, week int) ([]byte, error)

// Register extract
GetPatentRegisterExtract(ctx, date time.Time, period string) ([]byte, error)

Design Service

// Search designs
SearchDesigns(ctx, query string) ([]byte, error)

// Get design info by design number
GetDesignInfo(ctx, designNumber string) ([]byte, error)

// Get design image/thumbnail
GetDesignImage(ctx, designNumber, imageNumber string) ([]byte, error)
GetDesignThumbnail(ctx, designNumber, thumbnailNumber string) ([]byte, error)

// Weekly bulk downloads
GetDesignBibliographicDataXML(ctx, year, week int) ([]byte, error)
GetDesignImages(ctx, year, week int) ([]byte, error)

// Register extract
GetDesignRegisterExtract(ctx, date time.Time, period string) ([]byte, error)

Trademark Service

// Search trademarks
SearchTrademarks(ctx, query string) ([]byte, error)

// Get trademark info by application number
GetTrademarkInfo(ctx, applicationNumber string) ([]byte, error)

// Get trademark image/thumbnail
GetTrademarkImage(ctx, applicationNumber string) ([]byte, error)
GetTrademarkThumbnail(ctx, applicationNumber string) ([]byte, error)

// Weekly bulk downloads
GetTrademarkBibDataApplied(ctx, year, week int) ([]byte, error)
GetTrademarkBibDataRegistered(ctx, year, week int) ([]byte, error)
GetTrademarkBibDataRejected(ctx, year, week int) ([]byte, error)

// Register extract
GetTrademarkRegisterExtract(ctx, date time.Time, period string) ([]byte, error)

Streaming Downloads (Memory-Efficient)

Every bulk download and register extract method has a *Stream variant that writes to an io.Writer:

// Patent streams
GetDisclosureDocumentsXMLStream(ctx, year, week int, dst io.Writer) error
GetPatentSpecificationsXMLStream(ctx, year, week int, dst io.Writer) error
GetUtilityModelsXMLStream(ctx, year, week int, dst io.Writer) error
GetPublicationDataXMLStream(ctx, year, week int, dst io.Writer) error
GetApplicantCitationsXMLStream(ctx, year, week int, dst io.Writer) error
GetEuropeanPatentSpecificationsXMLStream(ctx, year, week int, dst io.Writer) error
GetDisclosureDocumentsPDFStream(ctx, year, week int, dst io.Writer) error
GetPatentSpecificationsPDFStream(ctx, year, week int, dst io.Writer) error
GetEuropeanPatentSpecificationsPDFStream(ctx, year, week int, dst io.Writer) error
GetUtilityModelsPDFStream(ctx, year, week int, dst io.Writer) error
GetPatentRegisterExtractStream(ctx, date time.Time, period string, dst io.Writer) error

// Design streams
GetDesignBibliographicDataXMLStream(ctx, year, week int, dst io.Writer) error
GetDesignImagesStream(ctx, year, week int, dst io.Writer) error
GetDesignRegisterExtractStream(ctx, date time.Time, period string, dst io.Writer) error

// Trademark streams
GetTrademarkBibDataAppliedStream(ctx, year, week int, dst io.Writer) error
GetTrademarkBibDataRegisteredStream(ctx, year, week int, dst io.Writer) error
GetTrademarkBibDataRejectedStream(ctx, year, week int, dst io.Writer) error
GetTrademarkRegisterExtractStream(ctx, date time.Time, period string, dst io.Writer) error

Configuration

config := &dpma.Config{
    Username: "your-username",           // Required
    Password: "your-password",           // Required
    BaseURL:  "https://dpmaconnect.dpma.de/dpmaws/rest-services", // Default
    Timeout:  20 * time.Minute,           // Request timeout (default: 20 minutes)
    HTTPClient: myCustomHTTPClient,      // Optional: provide your own *http.Client
}

client, err := dpma.NewClient(config)

Usage Examples

Download Patent PDF

ctx := context.Background()
pdf, err := client.GetPatentPublicationPDF(ctx, "DE102023000001A1")
if err != nil {
    log.Fatal(err)
}

err = os.WriteFile("patent.pdf", pdf, 0644)
if err != nil {
    log.Fatal(err)
}

Download Publication Week Data

ctx := context.Background()

zipData, err := client.GetDisclosureDocumentsXML(ctx, 2024, 45)
if err != nil {
    if _, ok := err.(*dpma.DataNotAvailableError); ok {
        fmt.Println("Data not available for this week")
        return
    }
    log.Fatal(err)
}

err = os.WriteFile("disclosure_202445.zip", zipData, 0644)
if err != nil {
    log.Fatal(err)
}

Stream Large Files

ctx := context.Background()

file, err := os.Create("patents_202445.zip")
if err != nil {
    log.Fatal(err)
}
defer file.Close()

err = client.GetPatentSpecificationsXMLStream(ctx, 2024, 45, file)
if err != nil {
    log.Fatal(err)
}

Search Designs

ctx := context.Background()

// Validate query against design field codes
if err := dpma.ValidateDesignQuery("INH=Samsung"); err != nil {
    log.Fatal(err)
}

results, err := client.SearchDesigns(ctx, "INH=Samsung")
if err != nil {
    log.Fatal(err)
}

fmt.Printf("Received %d bytes of XML results\n", len(results))

Register Extract

ctx := context.Background()

date := time.Date(2024, 10, 23, 0, 0, 0, 0, time.UTC)
data, err := client.GetPatentRegisterExtract(ctx, date, dpma.PeriodDaily)
if err != nil {
    log.Fatal(err)
}

fmt.Printf("Register extract: %d bytes\n", len(data))

Query Validation

The query sub-package provides a parser and validator for DPMAregister expert search syntax:

import "github.com/patent-dev/dpma-connect-plus/query"

// Parse and validate a patent query
q, err := query.ParseQuery("TI=Elektrofahrzeug AND INH=Siemens", query.ServicePatent)
if err != nil {
    log.Fatal(err)
}
if err := q.Validate(); err != nil {
    log.Fatal(err) // e.g. unknown field, unmatched parentheses
}

// Inspect the query
fmt.Println(q.GetFields())  // ["TI", "INH"]
fmt.Println(q.HasField("TI")) // true

// Validate against a specific service
q, _ = query.ParseQuery("MARKE=test", query.ServiceTrademark) // valid
q, _ = query.ParseQuery("MARKE=test", query.ServicePatent)    // invalid: unknown field

// Look up field definitions
f, ok := query.GetField("TI", query.ServicePatent)
fmt.Println(f.Description) // "title / designation"

// List all valid fields for a service
fields := query.GetValidFields(query.ServiceDesign)

Features

Tokenizer with support for quoted values, comparison operators (=, >=, <=, >, <), parentheses, and curly braces (procedure data)
Field validation per service (Patent, Design, Trademark) based on official DPMAregister field codes
Bracket and brace matching
Recognizes both English (AND, OR, NOT) and German (UND, ODER, NICHT) Boolean operators
Field lookup with German name, English description, and input type (text/date)

Search Query Syntax

All search methods use DPMAregister expert search syntax. The format is FIELD=value with Boolean operators AND, OR, NOT.

Patent Field Codes

Code	Description
`TI`	Title/designation
`INH`	Applicant/proprietor
`IN`	Inventor
`IC`	IPC classification
`AKZ`	File number
`PN`	Publication number
`PUB`	Publication date
`AB`	Abstract

Design Field Codes

Code	Description
`TI`	Designation
`INH`	Proprietor
`ENTW`	Designer
`ERZ`	Product(s)
`WKL`	Commodity class
`RN`	Registration number
`DNR`	Design number

Trademark Field Codes

Code	Description
`md`	Trademark text
`INH`	Proprietor
`WKL`	Class(es)

For a full reference, see the DPMAregister help pages:

Error Handling

The library provides custom error types for different scenarios:

// Resource not found (404)
if notFoundErr, ok := err.(*dpma.NotFoundError); ok {
    fmt.Printf("Not found: %s %s\n", notFoundErr.Resource, notFoundErr.ID)
}

// Data not available (common for old/future publication weeks)
if _, ok := err.(*dpma.DataNotAvailableError); ok {
    fmt.Println("Data not available for the requested period")
}

// Generic API errors
if apiErr, ok := err.(*dpma.APIError); ok {
    fmt.Printf("API error: %s (code: %s, HTTP %d)\n", apiErr.Message, apiErr.Code, apiErr.StatusCode)
}

// XML parsing failures (malformed response data)
if xmlErr, ok := err.(*dpma.XMLParseError); ok {
    fmt.Printf("Failed to parse response in %s: %v\n", xmlErr.Operation, xmlErr.Unwrap())
}

Date and Week Formatting

Publication Week Format

Publication weeks use YYYYWW format (6 digits):

pubWeek, err := dpma.FormatPublicationWeek(2024, 45)  // Returns "202445", nil

year, week, err := dpma.ParsePublicationWeek("202445")  // Returns 2024, 45, nil

Register Extract Date Format

Register extracts use YYYY-MM-DD format:

date := time.Date(2024, 10, 23, 0, 0, 0, 0, time.UTC)
dateStr := dpma.FormatDate(date)  // Returns "2024-10-23"

Services

DPMA Connect Plus provides three services:

Service	Description	Constant
Patents & Utility Models	Patent applications, grants, utility models	`dpma.ServicePatent`
Designs	Design applications and registrations	`dpma.ServiceDesign`
Trademarks	Trademark applications and registrations	`dpma.ServiceTrademark`

Package Structure

├── client.go              # Core client (Config, NewClient, GetVersion)
├── client_patent.go       # Patent service methods
├── client_design.go       # Design service methods
├── client_trademark.go    # Trademark service methods
├── errors.go              # Custom error types
├── helpers.go             # Date/week formatting, constants
├── query/                 # Query parser and field validation
│   ├── query.go           # Parser, tokenizer, validator
│   ├── fields.go          # Field definitions per service
│   └── query_test.go      # Query package tests
├── client_test.go         # Core unit tests
├── client_patent_test.go  # Patent unit tests
├── client_design_test.go  # Design unit tests
├── client_trademark_test.go # Trademark unit tests
├── integration_test.go    # Integration tests (real API)
├── generated/             # Auto-generated OpenAPI code
│   ├── types_gen.go       # Generated types
│   └── client_gen.go      # Generated client
├── openapi.yaml           # OpenAPI 3.0 specification
└── demo/                  # Interactive demo application
    └── demo.go

Implementation

This library follows a clean architecture:

OpenAPI Specification: Hand-crafted openapi.yaml based on official DPMA documentation
Code Generation: Types and client generated using oapi-codegen
Idiomatic Wrapper: Clean Go client wrapping generated code with error handling and convenience methods

Testing

Unit Tests (Mock Server)

Offline tests using mock HTTP server with realistic responses:

go test -v
go test -v -cover

Integration Tests (Real API)

Tests that make actual requests to the DPMA API:

export DPMA_CONNECT_PLUS_USERNAME=your-username
export DPMA_CONNECT_PLUS_PASSWORD=your-password

go test -tags=integration -v

Note: Integration tests require valid DPMA Connect Plus credentials and will skip if environment variables are not set.

Demo Application

An interactive demo application is included:

export DPMA_CONNECT_PLUS_USERNAME=your-username
export DPMA_CONNECT_PLUS_PASSWORD=your-password

cd demo
go run demo.go

The demo provides an interactive menu for testing all three services: patents, designs, and trademarks.

Implementation Status

All endpoints defined in the DPMA Connect Plus API are implemented. Verification status depends on the permissions granted to the test account.

Fully Verified

The following endpoints have been tested against the live API with real data:

Service	Endpoint	Description
General	`GetVersion`	Service version info
Patent	`SearchPatent`	Expert search
Patent	`GetRegisterInfo`	Register data for a patent
Patent	`GetFulltextXML` / `Stream`	Full-text XML
Patent	`GetFulltextPDF` / `Stream`	Full-text PDF
Patent	`GetDocumentIdList`	Document IDs for a publication week
Patent	`GetBulkFulltextXML` / `Stream`	Bulk full-text XML
Patent	`GetBulkFulltextPDF` / `Stream`	Bulk full-text PDF
Patent	`GetRegisterExtractXML` / `Stream`	Register extract
Patent	`GetDisclosureDocumentsXML` / `Stream`	Weekly disclosure documents
Design	`SearchDesign`	Expert search
Design	`GetDesignRegisterInfo`	Register data for a design
Trademark	`SearchTrademark`	Expert search
Trademark	`GetTrademarkRegisterInfo`	Register data for a trademark

Not Yet Verified (Permission-Restricted)

The following endpoints are implemented but could not be verified with the current test account. We are in talks with DPMA to achieve broader test coverage.

Service	Endpoint	Description
Patent	`GetPublicationDataXML` / `Stream`	Weekly publication data
Patent	`GetApplicantCitationsXML` / `Stream`	Applicant citations
Design	`GetDesignBibliographicDataXML` / `Stream`	Bibliographic bulk data
Design	`GetDesignImages` / `Stream`	Design images bulk download
Trademark	`GetTrademarkBibDataApplied` / `Stream`	Applied trademarks bulk data
Trademark	`GetTrademarkBibDataRegistered` / `Stream`	Registered trademarks bulk data
Trademark	`GetTrademarkBibDataRejected` / `Stream`	Rejected trademarks bulk data

Data Availability

Publication Data: Updated weekly
- Patents/Utility Models: Thursdays
- Designs/Trademarks: Fridays
Register Data: Updated daily
Historical Data: Varies by document type

Note: "Data not available" errors are common for:

Future publication weeks
Old publication weeks (before digital archiving)
Weeks with no publications

Development

Regenerating from OpenAPI

If the OpenAPI spec is updated:

go install github.com/oapi-codegen/oapi-codegen/v2/cmd/oapi-codegen@latest

oapi-codegen -package generated -generate types openapi.yaml > generated/types_gen.go
oapi-codegen -package generated -generate client openapi.yaml > generated/client_gen.go

Code Quality

go fmt ./...
go vet ./...
go test -v ./...

Related Projects

Part of the patent.dev open-source patent data ecosystem:

uspto-odp - USPTO Open Data Portal client (search, PTAB, XML full text)
epo-ops - EPO Open Patent Services client (search, biblio, legal status, family, images)
epo-bdds - EPO Bulk Data Distribution Service client

The bulk-file-loader uses these libraries for automated patent data downloads.

License

MIT License - see LICENSE file for details.

Credits

Developed by:

Wolfgang Stark - patent.dev - Funktionslust GmbH

Name		Name	Last commit message	Last commit date
Latest commit History 6 Commits
.github/workflows		.github/workflows
demo		demo
generated		generated
query		query
resources		resources
testdata		testdata
.gitignore		.gitignore
.golangci.yml		.golangci.yml
LICENSE		LICENSE
README.md		README.md
client.go		client.go
client_design.go		client_design.go
client_design_test.go		client_design_test.go
client_patent.go		client_patent.go
client_patent_test.go		client_patent_test.go
client_test.go		client_test.go
client_trademark.go		client_trademark.go
client_trademark_test.go		client_trademark_test.go
errors.go		errors.go
go.mod		go.mod
go.sum		go.sum
helpers.go		helpers.go
helpers_test.go		helpers_test.go
integration_test.go		integration_test.go
openapi.yaml		openapi.yaml
xml.go		xml.go
xml_test.go		xml_test.go

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DPMA Connect Plus Go Client

Getting Started

Authentication

Installation

Quick Start

API Methods

Common Operations

Query Validation

Patent Service

Design Service

Trademark Service

Streaming Downloads (Memory-Efficient)

Configuration

Usage Examples

Download Patent PDF

Download Publication Week Data

Stream Large Files

Search Designs

Register Extract

Query Validation

Features

Search Query Syntax

Patent Field Codes

Design Field Codes

Trademark Field Codes

Error Handling

Date and Week Formatting

Publication Week Format

Register Extract Date Format

Services

Package Structure

Implementation

Testing

Unit Tests (Mock Server)

Integration Tests (Real API)

Demo Application

Implementation Status

Fully Verified

Not Yet Verified (Permission-Restricted)

Data Availability

Development

Regenerating from OpenAPI

Code Quality

Related Projects

License

Credits

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