Begin with the operating model
Before comparing screens or features, describe who will use the platform and which actions they need to perform. A broker interface, an exchange with its own order book, and a portfolio dashboard have different responsibilities. Write down the intended markets, account roles, funding methods, and trading integrations. Ask the supplier to mark each requirement as included, configurable, dependent on another service, or custom work. This simple distinction makes competing proposals much easier to compare.
Follow a balance through its whole journey
Choose one example deposit and trace it through detection, confirmation, the account ledger, an order, and a withdrawal request. Ask how the system separates available funds from funds reserved for open orders. Then repeat the exercise with a cancelled order and a delayed callback. The goal is evidence of consistent accounting. A polished balance card cannot demonstrate that repeated events, partial fills, or interrupted requests leave the underlying records correct.
Make custody boundaries explicit
Identify which component can create addresses, access signing material, and authorize transfers. Request a diagram showing the application, wallet services, blockchain providers, and administrative controls. Clarify which credentials the buyer must supply and where they are stored. If an external custody provider is involved, understand what happens when it becomes unavailable. Do not assume that owning the application source automatically gives your team a complete, independently operable custody system.
Demonstrate failures, not just the happy path
A useful demonstration includes rejected orders, provider timeouts, repeated requests, and a worker restarting halfway through a job. Ask the team to show what the customer sees and what the operator can inspect. Look for bounded retries, clear states, and an audit trail that explains changes. Performance claims should come with a described workload and test environment. A fast demonstration on sample data is not a capacity guarantee for your expected traffic.
Inspect the actual handover
Agree on the repository contents, dependency versions, database migrations, installation instructions, and deployment responsibilities. Check whether the delivery includes administrative tools, background workers, and the components shown in the demonstration. Ask which assets or services require separate licenses. Have someone unfamiliar with the project follow the installation guide in a clean environment. Missing assumptions become visible quickly when the original developer is no longer completing the steps from memory.
Turn findings into acceptance criteria
End the review with a short, testable acceptance document. Specify the journeys that must work, the records that must reconcile, and the operational material that must be delivered. Record known exclusions and any independent security review your business requires before launch. At Codemen, the productive starting point is a scoped demonstration and a written delivery discussion. The right source package is the one your team can understand, operate, and responsibly extend.