--- title: "Questions from developers about KYA: 13 answers" url: https://knowyouragent.ch/en/knowledge/faq/developers lang: en updated: 2026-10-17 license: © Innopulse Consulting GmbH --- # Questions from developers about KYA: 13 answers Whoever builds KYA into their own systems has concrete technical questions. Here are the answers on package, formats, trust, results and operation, each with a reference to the in-depth pages. [Leutrim Miftaraj](https://knowyouragent.ch/en/about/leutrim-miftaraj), Founder, Innopulse Consulting GmbH Published 17 October 2026 ## What this is about This page summarizes the most common questions from integration. The guides on the engine in Node.js and the CI pipeline offer the way into code, and the error reference explains the meaning of every reason code. ## Questions and answers ### How do I integrate the engine? Through the @knowyouragent/verify-core package, which you install directly from knowyouragent.ch. The verify() function takes the evidence and options and returns a report with verdict, level and all checks. ### Which runtimes are supported? Node.js 20 or later and current browsers. The engine uses WebCrypto and has no runtime dependencies. ### Which formats does the engine verify? [SD-JWT VC](https://knowyouragent.ch/en/knowledge/glossary/sd-jwt-vc), JWS, kya-pack/1, kya-chain/1, IETF status lists, RFC 3161 timestamps, Verifiable Intent and HTTP signatures following RFC 9421, including Web Bot Auth. ### Does the engine load keys or status lists from the network? No. You pass everything the engine needs for trust as an option. Whatever is missing counts as not proven; this makes verification reproducible and independent of the network. ### Which algorithms are supported? ES256, ES384, EdDSA with Ed25519, RS256 and PS256. If an environment lacks Ed25519, the engine reports the check as not checked, never as invalid. ### What do the command line's exit codes mean? 0 stands for VALID, 1 for INVALID, 2 for INDETERMINATE and 64 for incorrect usage. In pipelines, every code other than 0 should fail the run. ### How do I handle INDETERMINATE? As missing evidence, not as success. The report names a reason code in the affected check, such as status_list_not_provided, showing what is missing. ### Is the result deterministic? Yes. The same inputs and the same verification time yield the same report and the same reportDigest. Set now to retrace verifications exactly later. ### How do I test my own implementation? With the public test vectors under Apache 2.0. Each vector contains input, options and the expected result down to the reason code. ### Can I use custom constraints in mandates? Yes, but the engine evaluates only the constraints of the verification profile. It reports unknown constraints with constraint_not_supported, and your system must check them itself. ### How fast is a verification? Verification runs locally in milliseconds to a few hundred milliseconds, depending on format, number of signatures and certificate chains. ### Which license applies to the engine? Apache 2.0. You can use it commercially, modify it and pass it on; the specification is licensed under CC BY 4.0. ### Where do I report bugs or deviations? Through the contact page. Helpful are the evidence or a reproduced test case, the options and the expected and actual reason code. ### Is there a browser version? Yes. The same engine runs on the verification page in the browser; the package contains a build that can be bundled into web applications. ### How are new versions of the engine published? With version number, changelog and checksum. Changes in behavior are traceable through the test vectors, and reason codes remain stable. ### Can I process certificates automatically? Yes. The report is JSON with a fixed structure: verdict, level, ten checks with status and reason code, facts and reportDigest. A published JSON schema describes the structure. ### Does the engine support delegation chains? Yes. It checks every level for signature, binding to the next level and narrowing of authority, and reports errors with dedicated reason codes. ## Sources - @knowyouragent/verify-core (Paket): [https://knowyouragent.ch/downloads/knowyouragent-verify-core-1.2.0.tgz](https://knowyouragent.ch/downloads/knowyouragent-verify-core-1.2.0.tgz) - KYA-Prüfprofil: [https://knowyouragent.ch/standard/pruefprofil](https://knowyouragent.ch/standard/pruefprofil) --- Quelle: https://knowyouragent.ch/en/knowledge/faq/developers · KYA – Know Your Agent