> For the complete documentation index, see [llms.txt](https://doc.api.tieto.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.api.tieto.com/open-banking-platform/sandbox-guide/certificates-and-applications.md). # Certificates and Applications Two things are needed before a call will go through: something that identifies the organization, and something that identifies the software. ## What you do 1. **Download the test certificates.** Open the Test Certificates page in the portal and download the regulatory test certificates. No qualified trust service provider, no purchase, no waiting. 2. **Create a client application** of the regulatory type. Sandbox applications need no certificate attached to them. 3. **Generate the API key** for that application version. Regulatory APIs in the sandbox authenticate with an application-specific API key rather than an OAuth client secret. The key is downloadable **once only** and stored as a hash — the platform cannot restore it. If you lose it, delete the application version and create another. That is not a sandbox shortcut; it is the same discipline that applies in production. ## What you learn **Identity and software are separate concerns, deliberately.** A TPP's organizational identity comes from certificates it obtains from QTSP; its software identity comes from applications it registers with you. Keeping them apart is what lets one TPP run several applications, rotate credentials, and retire a version without touching its regulatory standing. **An application is a scope, not just a name.** Each carries a type — regulatory, premium, or aggregation where offered — and a scope built from API group, version, API and specific operations. An application can hold several scopes, each covering one service at one version. Versions are assigned automatically from 1.0, and because each version has its own credentials, issuing a new version *is* the credential rotation mechanism. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://doc.api.tieto.com/open-banking-platform/sandbox-guide/certificates-and-applications.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.