Enterprise Integration Patterns Home

My ongoing thoughts about the present and future of integration, SOA and Web services. [see all]
37 Things or "Where have all my ramblings gone?"
25 Years of OOP
How to Scale an Organization? The same way you scale a system!
IT-Architekten: Angelpunkt der Digitalen Transformation im Unternehmen
Oct 19-20, 2016
Dec 1-9, 2016
Sydney, Melbourne, Brisbane
20 Years of Patterns' Impact
(IEEE Software)
Conversations Between Loosely Coupled Services
(Video on InfoQ)
Developing in a Service-oriented World
(Video on InfoQ)
SOA Patterns - New Insights or Recycled Knowledge?
Let's Have a Conversation
(IEEE Internet Computing)
Programming Without a Call Stack - Event-driven Architectures
(ObjektSpektrum, 2006)
Your Coffee Shop Does Not Use Two-Phase Commit
(IEEE Software)
Developing in a Service-Oriented World
(ThoughtWorks Whitepaper)
Integration Patterns with BizTalk Server 2004
(ThoughtWorks Whitepaper)
An Asynchronous World
(Software Development)
Test-Driven Development in Integration Projects
(ThoughtWorks Whitepaper)
XML Abuse
(Software Development)
"Starbucks Does Not Use Two-Phase Commit" selected for "The Best Software Writing"
Nearfield Communication (NFC) in Japan
(OOP 2012)
Embedded OSS
(OOP 2012)
Distributed Programming the Google Way
(Devoxx 2009)
Developing in a Service-Oriented World
(SOACon 2007)
Programming without a Call Stack: Event-driven Architectures
(SOACon 2007)
Software Visualization and Model Extraction
Conversations Between Loosely Coupled Systems
(SD West, 2006)
Enterprise Integration Patterns
(JAOO, 2003)
Microsoft MVP
IEEE Software Board Member

Patterns and Best Practices for Enterprise Integration

This site is dedicated to making the design and implementation of integration solutions easier. The solutions described here are relevant for a variety of integration tools and platforms such as IBM WebSphere MQ, TIBCO, Vitria, WebMethods (Software AG), or Microsoft BizTalk, messaging systems such as JMS, WCF, Rabbit MQ, or MSMQ, ESB's such as Apache Camel, Mule, WSO2, Oracle Service Bus, Open ESB, SonicMQ, Fiorano or Fuse ServiceMix plus other SOA and Web-service solutions.

All content on this site is original and is maintained by Gregor Hohpe. I have been building integration solutions for large clients for many years and enjoy sharing my findings with the community. You can find the most recent content in my Ramblings. Please contact me if you have suggestions or feedback.

Enterprise Integration Patterns

Enterprise integration remains more difficult than it should be. While integrating systems is inherently complex, one major stumbling blocks used to be the lack of a common vocabulary and body of knowledge for asynchronous messaging architectures. Under the guidance of Martin Fowler and Kyle Brown, Bobby Woolf and I filled this gap with a pattern language consisting of 65 integration patterns, which establish a technology-independent vocabulary and a visual notation to design and document integration solutions.

The full text for each pattern is available in the book Enterprise Integration Patterns, which also explores the advantages and "gotchas" of asynchronous messaging architectures. You can learn how to connect applications to a messaging system, how to route messages to the proper destination, and how to monitor the health of a messaging system. The patterns in the book come to life with examples implemented in different messaging technologies, such as SOAP, JMS, MSMQ, .NET, TIBCO and other EAI Tools. See for yourself by Downloading a sample chapter!

"The core language of EAI, defined in the book Enterprise Integration Patterns by Gregor Hohpe and Bobby Woolf, is also the core language of defining ESB flows and orchestrations, as seen in the ESB's developer tooling."
--Forrester Research
"If you are involved with the operation or development of an enterprise application, there will doubtless come a time when you will need to integrate your application with another using the emerging preferred approach of messaging. When that time comes, this book will be your most valuable reference."
--Randy Stafford, Oracle [More Testimonials]

New Book: Enterprise Transformation

37 Things Cover As enterprise integration remains a relevant topic some 13 years after Enterprise Integration Patterns was published, a new topic has become a major consideration for large enterprises: they are under pressure from so-called "digital disruptors" who attack unexpectedly with brand-new business models, operate free of legacy, and release enhanced products on a weekly basis. To compete in the digital age, traditional enterprises must transform not only their business model but also their IT departments.

I collected my experience as chief architect into a book to help IT architects or CTOs combine superb technical, communication, and organizational skill to successfully drive IT transformation in large organizations. The book titled 37 Things One Architect Knows About IT Transformation is available as E-Book on leanpub.com or as print book on lulu.com.

Why Do We Need Integration?

Today's business applications rarely live in isolation. Users expect instant access to all business functions an enterprise can offer, regardless of which system the functionality may reside in. This requires disparate applications to be connected into a larger, integrated solution, which is generally achieved through some form of "middleware". Middleware provides the "plumbing" such as data transport, data transformation, and routing.

What Makes Integration so Hard?

Architecting integration solutions is a complex task. There are many conflicting drivers and even more possible 'right' solutions. Whether the architecture was in fact a good choice usually is not known until many months or even years later, when inevitable changes and additions put the original architecture to test. Unfortunately, there is no "cookbook" for enterprise integration solutions. Most integration vendors provide methodologies and best practices, but these instructions tend to be very much geared towards the vendor-provided tool set and often lack treatment of the bigger picture, including underlying guidelines, principles and best practices.

Asynchronous Messaging Architectures

Asynchronous messaging architectures have proven to be the best strategy for enterprise integration because they allow for a loosely coupled solution that overcomes the limitations of remote communication, such as latency and unreliability. That's why most EAI suites and ESB's are based on asynchronous messaging. Unfortunately, asynchronous messaging is not without pitfalls. Many of the assumptions that hold true when developing single, synchronous applications are no longer valid. Vendor-independent design guidance helps developers avoid these pitfalls so they can build robust integration architectures based on asynchronous messaging.

How can Patterns Help?

Patterns are a proven way to capture experts' knowledge in fields where there are no simple “one size fits all” answers, such as application architecture, object-oriented design, or message-oriented integration . Each pattern tackles a specific problem by discussing design considerations and presenting an elegant solution that balances the forces. Often the solution is not the first approach that comes to mind, but one that has evolved through actual use over time. As a result, each pattern incorporates the experience that senior developers and architects have gained by repeatedly building solutions and learning from their mistakes. Thus, patterns are not “invented” but discovered and observed from actual practice.

What am I Reading Right Now?

Designing Delivery: Rethinking IT in the Digital Service Economy, Sussna, O'Reilly 2015

This book strikes a great balance between drawing on theoretical foundations (cybernetics, complex systems theory) and real-world examples to explain why and how traditional IT organizations must transform to support the business in a digital world where customers expect new features to be delivered daily, but do not tolerate downtimes even though systems are becoming ever more complex. A book to hand to all IT managers.

DevOps: A Software Architect's Perspective, Bass, Weber, Zhu, Addison-Wesley 2015

This book that takes the (cloud) architecture viewpoint on DevOps, which is a great compliment e.g. to The Phoenix Project, which gives you the story behind DevOps and the motivation. The SEI titles can be a bit encyclopedic, but are thorough and this one is refreshingly close to real-world cloud solutions and tooling. A must read if you deal with development organizations that are moving (or should be moving) to the cloud.

Table of Contents
Solving Integration Problems using Patterns
Integration Styles
File Transfer
Shared Database
Remote Procedure Invocation
Messaging Systems
Message Channel
Pipes and Filters
Message Router
Message Translator
Message Endpoint
Messaging Channels
Point-to-Point Channel
Publish-Subscribe Channel
Datatype Channel
Invalid Message Channel
Dead Letter Channel
Guaranteed Delivery
Channel Adapter
Messaging Bridge
Message Bus
Message Construction
Command Message
Document Message
Event Message
Return Address
Correlation Identifier
Message Sequence
Message Expiration
Format Indicator
Interlude: Simple Messaging
JMS Request/Reply Example
.NET Request/Reply Example
JMS Publish/Subscribe Example
Message Routing
Content-Based Router
Message Filter
Dynamic Router
Recipient List
Composed Msg. Processor
Routing Slip
Process Manager
Message Broker
Message Transformation
Envelope Wrapper
Content Enricher
Content Filter
Claim Check
Canonical Data Model
Interlude: Composed Messaging
Synchronous (Web Services)
Asynchronous (MSMQ)
Asynchronous (TIBCO)
Messaging Endpoints
Messaging Gateway
Messaging Mapper
Transactional Client
Polling Consumer
Event-Driven Consumer
Competing Consumers
Message Dispatcher
Selective Consumer
Durable Subscriber
Idempotent Receiver
Service Activator
System Management
Control Bus
Wire Tap
Message History
Message Store
Smart Proxy
Test Message
Channel Purger
Interlude: Systems Management Example
Instrumenting Loan Broker
Integration Patterns in Practice
Case Study: Bond Trading System
Concluding Remarks
Emerging Standards
Revision History