Building a resilient asynchronous workflow implies a number of challenges including managing state, retries, auditability, and observability. A workflow orchestration solution abstracts away state management and provides retries, auditability, and observability out-of-the-box. Using a workflow orchestration solution helps greatly to get a simplified view of any data pipeline, asynchronous system, or event-driven system. You can adopt and integrate a workflow orchestration solution like Temporal into your existing platform in stages or use it only for parts of your workflow. Twilio is a customer engagement platform that allows you to engage with your customers on your application using different channels like Voice, Messaging, Whatsapp, email, video. When you think of SMS, one of the big problems with SMS is spam. Additionally, there’s a lot of phishing going on over SMS (smishing). Due to the increase in spam messages, many consumers have lost trust in SMS as a form of communication. In the US, A2P 10DLC is the standard that carriers have implemented to regulate this communication pathway. A2P 10DLC improves the end-user experience by making sure consumers can opt in and out of messaging and also know who is sending them messages. It also benefits businesses, offering them higher messaging throughput, brand awareness, and accountability. To be compliant with A2P messaging, you need to register your application at three different levels. First, you will register your brand or business, which will be manually reviewed and approved. Next, you need to register your campaign, where you will detail what messages you are going to send, for example, sending two-factor authentications for account setup and login as well as some kind of notifications. Here, again, your use case will be vetted by someone and you may be required to provide additional detail about your use case. Finally, you are required to register a set of phone numbers you will use to send messages. In this article, we will discuss what problems we had to solve at Twilio to efficiently build a resilient and scalable asynchronous system to handle a complex workflow implementing A2P Messaging Compliance and the advantages we got from adopting a Workflow Orchestration solution. How Twilio implemented A2P compliance platform We originally built the A2P compliance platform using a state machine to orchestrate different registration processes described above. This system was built using an event-driven architecture and communicated using queues and ensured event processing at a specific rate adhering to the downstream rate limits. Over time, this platform evolved into a complex system which became hard to maintain (state m
