A brokerage API can shorten the path from product idea to connected account. It can also become a long-term source of edge cases, support work, and broker-by-broker maintenance.
The useful question is not simply, “How many brokers are on the list?” It is: Can this integration support the exact user journey, data, actions, and operating model our product needs?
This checklist gives product and engineering teams a practical way to answer that question before committing to an integration.
1. Start with the workflow, not the logo count
Write down the smallest complete workflow your product must support. For a trading journal, that might be:
- A user connects a brokerage account.
- The product reads accounts, orders, positions, balances, and transactions.
- Changes arrive quickly enough to keep the journal useful.
- The connection can be repaired when a broker requires the user to sign in again.
A copy-trading or investing product may also need order placement, modification, cancellation, and lifecycle updates. Those are different requirements from read-only aggregation.
Evaluate coverage against that workflow. A broker name on an integration page does not, by itself, prove that every resource or action is available. Access depends on the broker, the connection method, the user's permissions, and the API product you are using.
Turn the workflow into a capability matrix: providers down the left, required resources and actions across the top. Mark each cell documented, tested, partially supported, or unverified. Public integration directories are useful discovery tools, but the matrix should reflect what your team has actually proved.
2. Inspect the connection and consent model
The connection flow is part of your product experience. Check how the API handles:
- user authentication and consent;
- short-lived client sessions;
- multi-factor authentication and broker verification steps;
- expired or revoked connections;
- account selection when a user has more than one account;
- the boundary between your user identity and the provider's account identity.
A strong integration keeps long-lived server credentials away from the browser and gives the user a clear, contained way to connect. It should also tell your application when the connection needs attention rather than leaving you to infer that from missing data.
Prefer an architecture where your server creates a short-lived connection session and the client receives only what it needs to complete consent. During review, trace what is stored in the browser, what persists on your server, how users revoke access, and how your own user identifier maps to the provider's connection record.
3. Compare the data model with your product model
Every brokerage represents accounts, assets, orders, fills, positions, and transactions a little differently. An aggregation layer is valuable when it absorbs those differences without erasing information your product needs.
Ask for representative responses and map them into your own domain model. Pay particular attention to:
- stable identifiers;
- order type, side, quantity, price, and time-in-force;
- partial fills and status transitions;
- position quantities and cost information;
- balance types and currency;
- timestamps and time zones;
- pagination and historical depth;
- null, unknown, and provider-specific values.
Do not stop after one happy-path payload. Test at least one awkward case: a partially filled order, an expired connection, an account with no positions, or a provider that omits an optional field.
Normalization can reduce schema work, but it can also hide provider-specific detail. Check whether the API preserves raw identifiers, exposes unsupported or unknown values safely, and documents which fields may be absent. Your application should degrade deliberately instead of treating every missing field as an error.
4. Test freshness and event delivery
“Real time” is too vague to use as an acceptance criterion. Define a concrete freshness target for each workflow.
For example, a portfolio summary may tolerate periodic updates. An order-status screen or copier workflow needs much faster lifecycle information. The upstream broker matters: event-capable providers can surface changes immediately, while polling-only providers update after the next successful retrieval.
Evaluate both the read path and the event path:
- Which resources have webhook events?
- Are order and transaction lifecycle changes included?
- Can you receive balance, position, and account changes?
- How are retries, duplicate events, and out-of-order delivery handled?
- How do you verify a webhook signature?
- Can your team replay or test a delivery safely?
Design the consumer to be idempotent: store an event identifier, tolerate duplicates, and make repeated processing safe. Add a reconciliation job that periodically compares webhook-derived state with the read API. Webhooks improve latency; reconciliation protects correctness.
5. Prove the integration in a sandbox
A useful sandbox lets you test the same concepts and SDK methods you will use later, without connecting a production brokerage account.
Your first proof should cover the full path:
- Create a test API key.
- Initialize a client session.
- Complete the connection flow.
- Read the core resources.
- Trigger or simulate an event.
- Exercise an error and a reconnection path.
Judge a sandbox by fidelity, not just availability. The best test environment mirrors production schemas, authentication states, error shapes, and event delivery closely enough that your integration code does not need a separate architecture. As one concrete implementation example, the Finatic quick start uses sandbox credentials and generated data to exercise account, order, position, and balance workflows.
6. Model failures before launch
Brokerage connectivity crosses several systems you do not control. Plan for failures as normal operating states.
Ask how the API represents:
- user action required;
- invalid or expired credentials;
- provider downtime;
- permission changes;
- rate limits;
- delayed synchronization;
- unsupported resources or actions;
- webhook delivery failure.
The response should be useful to both engineers and customer support. A generic error string may be enough for a log, but it is rarely enough to tell a user what to do next.
Also inspect the API's pagination, retry guidance, idempotency behavior, status model, and request limits. These details determine whether your integration remains predictable under load.
7. Price the maintenance, not only the API call
The direct API price is only one part of the cost. Include:
- broker-specific implementation and testing;
- changes to authentication flows;
- schema drift and new enum values;
- webhook operations;
- connection-repair support;
- monitoring and reconciliation;
- adding the next provider.
This is where an aggregation layer should earn its place. The goal is not merely to proxy a request. It is to reduce the amount of provider-specific code and operational work your team owns as the product expands. Compare that reduction against the cost of dependency, migration, and any gaps your team must still maintain.
A simple evaluation scorecard
Before choosing a provider, score each category from 0 to 2:
- 0: unavailable or unverified;
- 1: partially supported, with known gaps;
- 2: proven in a test that matches your workflow.
Use these categories:
- required broker and account coverage;
- authentication and consent;
- required data resources;
- trading actions, if applicable;
- freshness and webhooks;
- sandbox fidelity;
- errors and reconnection;
- SDK and documentation quality;
- monitoring and support;
- total maintenance cost.
The score is not a universal ranking. Weight the categories around your product. A journal may care most about historical transactions and reliable synchronization; a trading product may put permissions, order semantics, and lifecycle events first.
Put the scorecard into a proof
Run the same test script against every serious option and keep the evidence: sample payloads, event timings, failure cases, reconnection results, and unresolved gaps. A repeatable proof makes the decision easier to explain and gives the implementation team a useful acceptance suite after the vendor is chosen.
If Finatic is on your shortlist, use the integrations directory to identify candidate providers and the quick start to run the workflow in a sandbox. Apply the same scorecard you would use for any other option. For ambiguous coverage, send one specific workflow—broker, resources, actions, and freshness target—rather than asking whether an integration is supported in the abstract.