Flow provides public access nodes for multiple networks that developers can use to send transactions and fetch state. These nodes provide access to the Flow network via an API and offer two types of APIs: HTTP API and gRPC.
Testnet access nodes can be accessed at :
access.devnet.nodes.onflow.org:9000
Mainnet access nodes can be accessed at:
access.mainnet.nodes.onflow.org:9000
If you're just getting started, you can read our guide on Setting Up a Flow Access Node for running a permissionless access node. However, as your product matures, you may want to run your own node due to the rate limits on the public access nodes. You can start with a Light (Observer) Node or use a third-party provider like Quicknode.