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OSIsoft is pleased to announce the release of PI Web API 2018 SP1. This is a standalone installation kit available at, and is grouped together with PI Server downloads. The PI Web API is a suite of REST services that provide access to PI System data. The product is a member of the Developer Technologies suite of products and is targeted at providing cross-platform, multi-user programmatic access. Some highlights of this release are:

  • Notifications
    • Read for child NotificationContactTemplates
    • Read for NotificationPlugIn
    • Read, create, update, and delete for SecurityEntries on NotificationRules, NotificationRuleTemplates and NotificationContactTemplates
    • Create, update and delete for NotificationRules, NotificationRulesTemplates, NotificationContactTemplates and NotificationRuleSubscribers
    • GetByPath endpoints for NotificationContactTemplates, NotificationRules, and NotificationRuleTemplates
    • Search endpoint for NotificationContactTemplates
  • Stream Sets GetJoined Endpoint
    • Returns a set of recorded values (x-axis) with another set of data for any number of streams (Y, Y', Y''... axis) that are interpolated based on the points returned for the x-axis
  • Stream Updates (CTP)
    • Client code will be notified of changes in AF metadata through an Exception item in the response payload.
    • The selectedFields parameter is now honored in both registration and poll for updates.
    • Responses now include PreviousEventAction information with each data value.
    • Error messages are returned for markers that are no longer valid with every poll using that marker. Previously, the error message would be returned only once.
  • Expose 'Paths' and 'DataReference' properties on objects of attribute
  • Expose 'Paths' property on objects of element
  • The version of Web ID returned by PI Web API can be configured
    • PI Web API instances that run 2018 SP1 can now work together with older versions behind a load balancer since they can be configured to return the same version of Web ID


To download, visit the OSIsoft Customer Portal. Installation kits are grouped with PI Server downloads.

With the new release of PI Web API, OSIsoft is pleased to announce some updates  to our getting started material for developers.  

To facilitate developer learning and best practice use of the latest PI Web API, we will be supporting the release with:

1)      New code samples on Github

2)      New private online course for PI Web API developers - available on PI Square in mid-June 2019

These additions will replace the previous client libraries for PI Web API, removed from GitHub in November of 2018, with new code samples developed and approved by OSIsoft engineering.

In addition, with the release of PI Web API 2018 SP1, we will be removing the inclusion of "Open API Specification" (formerly known as "Swagger™ Specification") from PI Web API. While the Open API Specification facilitated the rapid generation of code libraries while creating code, it had not been officially tested and validated with the wide diversity of code generating tools available to developers. In cases some code generators could create sub optimal code.

To follow best practices, and help developers learn how to build optimal code for PI Web API, OSIsoft decided to remove the Open API Specification from the latest PI Web API installation.  The new, approved code samples on GitHub are the preferred approach to learn, and ensure optimal coding practices.

If you have downloaded, and have access to the client libraries or the Open API Specification, feel free to continue to use these for learning needs however please do not incorporate the sample client libraries into your production applications. For those using Open API Specification, please recognize that code may not be optimized and may require further review and optimization.

If you have any questions about the new code samples or changes, please contact Frank Garriel, Technical Product Manager (

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