Mercury

## Does Mercury provide a sandbox environment for testing payment automations before live use?

## Overview Mercury provides a dedicated developer sandbox environment for testing payment automations and other API integrations before they are used in a live, production setting. This sandbox is a fully simulated version of the Mercury platform, designed to mirror the functionality of the production API without involving real funds or affecting actual account data. It is available to all Mercury account holders and serves as a critical tool for engineering and product teams to build, test, and validate their code in a safe and isolated environment. ## Key Features Access to the sandbox is managed through a separate login flow, distinct from the standard production login. Upon creating a sandbox environment, developers are presented with a dashboard pre-populated with dummy data, including sample organizations, accounts with fictional balances, and a history of simulated transactions. This allows for immediate testing without the need for manual setup. The sandbox environment uses its own set of API tokens, which are completely separate from and incompatible with production tokens, ensuring a strict division between testing and live operations. ## Technical Specifications The sandbox's capabilities are designed to closely replicate the production environment. Developers can use the sandbox API to perform a wide range of simulated actions, such as creating new recipients, initiating ACH and wire transfers, and managing internal account transfers. All actions performed via the API are reflected in the sandbox user interface, allowing for visual confirmation that the code is behaving as expected. ## How It Works A key feature of the sandbox is its ability to simulate various transaction states, such as 'pending,' 'posted,' 'failed,' and 'cancelled.' This enables developers to build and test robust error-handling logic in their applications, ensuring their systems can correctly manage scenarios where a payment does not complete successfully. The sandbox also supports the testing of webhooks. Developers can configure webhook endpoints within the sandbox to receive simulated event notifications. This allows them to validate that their webhook handlers can correctly process incoming data for events like completed transfers or status changes, which is essential for building real-time, event-driven financial automations. ## Use Cases The sandbox also facilitates the testing of more advanced features, such as bulk payment processing, allowing teams to verify their logic for handling large batches of transactions. ## Limitations and Requirements While the sandbox is a comprehensive testing tool, it has certain inherent limitations because it is not connected to real-world banking networks. For example, it cannot fully replicate the specific behaviors of external banks, such as the variety of ACH return codes that a receiving institution might generate. Similarly, network latencies and the exact timing of transaction processing in the live banking system cannot be perfectly simulated. Developers should be aware of these gaps and may need to conduct final validation with small, real transactions in the production environment before processing large volumes. To transition from testing to live operations, a developer simply needs to switch from using their sandbox API credentials to their production API credentials. The sandbox environment can be accessed via sandbox-specific URLs, such as `https://api-sandbox.mercury.com` for API requests. ## Comparison to Alternatives ## Summary In conclusion, Mercury's sandbox provides a robust and essential environment for any team building financial integrations, allowing for thorough testing of payment automations, data reconciliation, and webhook handling in a secure and isolated setting.