Skip to content
With Markets+, the Southwest Power Pool (SPP) is taking a significant step forward in modernizing how market participants exchange data. While existing SPP markets use SOAP-based web services, the Markets+ platform will use RESTful APIs—a modern, cloud-native framework that makes participation faster, lighter, and easier to maintain. By adopting REST from the outset, SPP is aligning Markets+ with today’s flexible, efficient, and widely compatible communication standards.
This upgrade will redefine how utilities and market participants interact with SPP’s newest market, setting the stage for a more connected and agile energy ecosystem. Here’s what you need to know.
How Markets+ Will Handle Data Exchange
Simple Object Access Protocol (SOAP) and Representational State Transfer (REST) are two different approaches to Application Programming Interface (API) design. Both define how applications exchange data, but they take very different approaches to integration.
SOAP is a highly structured protocol that relies on XML-based messages. Each message includes extensive formatting and tagging, making it heavy and rigid. REST, in contrast, is an architectural style that supports lightweight, flexible communication using JSON, XML, or other formats.
Figure 1 highlights key differences between SOAP and REST.
Figure 2 shows how these differences play out in the real world. You can see that a typical SOAP message includes extra formatting and tags even for basic data requests, while REST delivers the same information using a much simpler structure.
For Markets+, SPP is duplicating selected services and rebuilding them using RESTful APIs. Shared legacy interfaces remain on SOAP to keep existing market operations running smoothly (Figure 3).
What REST Means for Markets+ Participants
The switch to RESTful APIs provides market participants with a more streamlined and efficient way to connect to Markets+.
Simpler Integration
REST eliminates the need for complex XML schemas and heavy middleware, making integrations easier to build and maintain. Developers can also access data more quickly and iterate faster.
Faster Updates
Participants gain real-time access to market data, improving workflows for settlements, forecasts, and operations. Large, cumbersome data payloads are no longer a bottleneck, enabling more responsive applications.
Better Compatibility
REST aligns Markets+ with modern IT tools, cloud services, and analytics platforms, ensuring smooth integration with current systems and other technologies participants may use.
Future-Proofed
Building on REST establishes a foundation that meets global API standards, reducing the need for costly upgrades as technology evolves.
Enhanced Security
Modern authentication and encrypted endpoints provide secure, compliant communication, so faster, lighter access does not compromise data protection.
"Switching from SOAP to REST isn’t just about following trends — it’s about making life easier for developers and systems alike. REST is simpler, cleaner, and aligns better with how the modern web works. Instead of dealing with bulky XML and complex protocols, you get to work with straightforward HTTP methods and lightweight JSON. It’s also faster and more scalable. Because REST is stateless, each request stands on its own, which makes it a great fit for cloud environments and microservice architectures. And since it integrates easily with web, mobile, and other platforms, it’s a natural choice for building flexible, connected systems. In the end, REST helps teams move faster, reduce overhead, and spend more time building value — not wrestling with the protocol."
Navigating the Markets+ REST Transition
PCI Energy Solutions fully supports SPP’s decision to adopt REST for Markets+, viewing it as a significant step forward for market integration. We are actively aligning our software and support with the rollout to ensure our customers remain REST-ready, tested, and optimized. Our team participates in SPP’s Markets+ Technical Implementation Strike Team, giving us direct access to SPP expertise and enabling us to address integration challenges early in the process.
To help participants implement REST endpoints efficiently, PCI provides multiple resources, including customer round tables and webinars.
Our specialized AI assistant, M+ BOT, serves as a knowledgeable guide for Markets+ integration. Key features include:
- Expert Guidance: Get answers to detailed, actionable questions about Markets+ operations, rules, and strategies by querying a curated knowledge base of the latest official SPP documentation.
- Accurate and Current: M+ Bot undergoes weekly validation, with the knowledge base updated whenever new protocols are released, ensuring high confidence in the guidance provided.
- Verifiable Answers: M+ Bot provides links to the underlying documentation, allowing users to confirm answers directly.
- Knowledge Sharing: M+ Bot contributes to the broader knowledge base by generating informative articles on key Markets+ topics.
M+ Bot
Query our free, expert curated, SPP Markets+ AI chatbot
PCI also attends in-person SPP meetings to ensure customers stay informed, aligned, and prepared for upcoming market changes. We’ll be at the Markets+ Participant Executive Committee (MPEC) meeting in November and the Markets+ Change User Forum (MCUF) meeting in December. If you’ll be attending, we’d love to connect. Reach out to our team with your questions, feedback, or to discuss key Markets+ topics.
Making the Most of Markets+
By adopting RESTful APIs, Markets+ provides lighter, faster, and more flexible integration points, enabling utilities and market participants to use a modern, maintainable platform for exchanging data. PCI combines proactive system readiness with close coordination and support, helping participants navigate the Markets+ REST transition smoothly.
Learn more about how PCI Energy Solutions can help your organization optimize participation on our SPP Markets+ page.
