JWT Encoder Spring Boot

This tool encodes JSON Web Tokens by taking a header and payload, applying a cryptographic signing algorithm, and emitting a compact token. It is designed for Spring Boot development workflows where tokens are needed for API testing, mocks, and sample authentication flows in local or CI environments.
Conceptually, encoding follows RFC 7515: the header and payload are base64url-encoded, concatenated with dots, and signed to produce the signature. For HS256/HS384/HS512, the signature uses HMAC with SHA-256/384/512 and the provided secret. The resulting token can be verified by recipients with the same secret.
Users include backend developers, QA engineers, security testers, and DevOps teams who need deterministic tokens quickly without relying on a central auth service. The tool supports standard claims (exp, iat, nbf) and custom claims, enabling realistic token behavior in tests and development pipelines.
Core features include required header and payload inputs, algorithm selection, guidance on secret management, claim customization, and output in the JWT compact form. Validation helpers verify syntax and compatibility, while a deterministic encoder ensures reproducible results across runs. It also provides clear guidance on best practices for secret handling, and it is explicitly intended for development and testing workflows, not production use.