Overview: RPC requests are an application’s gateway to the Solana cluster. The requests are serviced by aptly named RPC Nodes, which are typically dedicated to the task rather than participating in consensus. Nevertheless, from an application user’s perspective, poor RPC performance is no different from poor cluster performance. To give your users a great experience and show off Solana’s speed and low-latency, it is important to have RPC infrastructure that is up to the task.
Development: Developers are encouraged to use a local cluster during development, especially in the early stages and for testing. Local clusters are more flexible than the public offerings, granting the freedom to run unoptimized early iterations. The easiest way to run a local cluster is with the
solana-test-validator binary, included in the Solana CLI Tools suite. Once the application reaches a stable state, deploying on a public cluster becomes more appropriate.
Like all code optimization tasks, when it comes to RPC requests, less is more. Avoid making frequent, repetitive calls for the same data. Avoid building clients that make RPC requests directly. “Backend-less dApps” are a myth; you are just pummelling someone else’s infrastructure. Cache expensive calls (especially
getConfirmedBlock) in an app-optimized way and serve your users from the cache. Taking the time to optimize your code before going live can save you a lot of headaches from poor user experience reports, and can significantly reduce your infrastructure spend.
Several providers offer free RPC access to the public Solana clusters. These services are good for real-world testing, early demos, and small, private beta programs. Keep in mind that you get exactly what you are paying for. Free services typically do not autoscale, are rate-limited, offer no SLA, and are not afraid to ban abusers. When an application is ready to be opened to the public, it is time to invest in private RPC access.
Some free RPC providers
Due to the variability in RPC requirements between applications, generalized public RPC infrastructure rarely fits the bill. To ensure users get a good experience, public facing applications need to secure their own private RPC access. This will allow you to autoscale based on user demand, relax rate limits according to your application, and have peace of mind that other applications’ users won’t crowd yours out. Several organizations offer high-availability, on-demand RPC services; see below. If none of the providers are a good fit and you’re up to the task of running your own RPC service, please reach out to the Solana Foundation for guidance.