# alif10151/jwt_checking_tool architecture

> Architecture diagram of the GitHub repository alif10151/jwt_checking_tool, generated by GitDiagram from its file tree, README and a sample of source files (last updated 2026-06-27). It is an AI-made overview: check details against the source.

- Interactive diagram: https://gitdiagram.com/alif10151/jwt_checking_tool
- Repository: https://github.com/alif10151/jwt_checking_tool

## Overview

1. **What this repo is**
   - A small Go-based JWT utility that serves a browser UI and exposes server-side JWT operations: decode, verify, and likely token creation/validation support.
   - The architecture is intentionally simple: a single Go service plus a static HTML client.

2. **Runtime and top-level shape**
   - `main.go` is the application entrypoint.
   - The app appears to run as a local HTTP server on port `8080`, serving both the UI and the backend endpoints the UI talks to.

3. **Client boundary**
   - `client/index.html` is the entire frontend surface in the tree.
   - This suggests a lightweight, mostly static UI rather than a full SPA framework.
   - The browser is the primary interaction point: users paste a JWT and secret, then trigger server-side processing.

4. **HTTP handler layer**
   - `handlers/` holds request-facing logic and is the boundary between the HTTP server and JWT business logic.
   - `handlers/cors.go` indicates cross-origin support, so the service may be callable from a browser hosted on a different origin or used in a more flexible local setup.
   - `handlers/create_jwt.go` suggests an endpoint or handler for building/signing JWTs in addition to verification-related actions.

5. **JWT processing utilities**
   - `Utility/decoder.go` and `Utility/verify.go` contain the core JWT logic.
   - This layer likely performs:
     - token parsing and base64 decoding,
     - extraction of header/payload claims,
     - signature verification against a provided secret.
   - This is the main business-logic boundary: handlers orchestrate, utilities do the JWT work.

6. **Response/data shaping**
   - `skeletons/jwt_skeletons.go` likely defines reusable response shapes or example token structures used by the handlers/utilities.
   - In architecture terms, this is the shared schema layer for the data passed back to the UI, such as decoded header/payload output and verification status.

7. **Primary data flow**
   - User inputs JWT + secret in the browser.
   - The client sends the request to the Go server.
   - A handler receives the request, invokes the utility layer to decode and/or verify the token, and returns structured results.
   - The browser renders the decoded claims, header information, and verification outcome.

8. **Validation path**
   - The key functional path is “decode first, then verify.”
   - Decoding extracts visible token data regardless of signature correctness.
   - Verification uses the provided secret to confirm authenticity and integrity, returning pass/fail state to the UI.

9. **Separation of concerns**
   - `client/` handles presentation only.
   - `handlers/` handles HTTP concerns, request parsing, CORS, and response writing.
   - `Utility/` contains the JWT algorithms and parsing logic.
   - `skeletons/` holds shared shapes or canned data structures.
   - This makes the repo easy to diagram as a three-layer flow: browser → handlers → utility.

10. **Infrastructure and dependencies**
   - The only explicit runtime dependency is Go 1.20+.
   - There is no sign of external services, databases, queues, or cloud infrastructure.
   - The architecture is self-contained and local-first, which fits the “fast and lightweight” description in the README.

11. **How to draw it**
   - Draw a single Go service box with `main.go` at the center.
   - Inside it, show:
     - HTTP server / routing,
     - handler layer,
     - JWT utility layer,
     - shared skeleton/schema layer.
   - Outside it, draw a browser client that sends token/secret input and receives decoded/verified output.

12. **Important boundary to preserve**
   - The repo’s key architectural seam is between request handling and JWT logic.
   - Keeping verification/decode logic in `Utility/` prevents the UI and handler code from becoming coupled to JWT internals, which is the main design constraint visible from the file layout.

Main entry points: [`handlers`](https://github.com/alif10151/jwt_checking_tool/tree/main/handlers) (Handlers), [`Utility`](https://github.com/alif10151/jwt_checking_tool/tree/main/Utility) (JWT utils), [`client/index.html`](https://github.com/alif10151/jwt_checking_tool/blob/main/client/index.html) (Browser UI), [`skeletons/jwt_skeletons.go`](https://github.com/alif10151/jwt_checking_tool/blob/main/skeletons/jwt_skeletons.go) (Skeletons)

## Diagram (Mermaid)

```mermaid
flowchart TD

subgraph group_client["Client"]
  node_clientui["Browser UI<br/>static client<br/>[index.html]"]
end

subgraph group_server["Go Service"]
  node_main["main.go<br/>entrypoint<br/>[main.go]"]
  node_router["HTTP server<br/>routing"]
  node_handlers["Handlers<br/>http layer"]
  node_createjwt["Create JWT<br/>endpoint<br/>[create_jwt.go]"]
  node_cors["CORS<br/>middleware<br/>[cors.go]"]
  node_utils["JWT utils<br/>core logic"]
  node_decoder["Decode<br/>parser<br/>[decoder.go]"]
  node_verify["Verify<br/>signature<br/>[verify.go]"]
  node_schema["Skeletons<br/>shared schema<br/>[jwt_skeletons.go]"]
end

node_clientui -->|"JWT requests"| node_handlers
node_main -->|"boots"| node_router
node_router -->|"serves"| node_clientui
node_router -->|"dispatches"| node_handlers
node_handlers -->|"applies"| node_cors
node_handlers -->|"creates"| node_createjwt
node_handlers -->|"calls"| node_utils
node_utils -->|"decodes"| node_decoder
node_utils -->|"verifies"| node_verify
node_handlers -->|"shapes"| node_schema
node_schema -->|"renders"| node_clientui

click node_main "https://github.com/alif10151/jwt_checking_tool/blob/main/main.go"
click node_handlers "https://github.com/alif10151/jwt_checking_tool/tree/main/handlers"
click node_createjwt "https://github.com/alif10151/jwt_checking_tool/blob/main/handlers/create_jwt.go"
click node_cors "https://github.com/alif10151/jwt_checking_tool/blob/main/handlers/cors.go"
click node_utils "https://github.com/alif10151/jwt_checking_tool/tree/main/Utility"
click node_decoder "https://github.com/alif10151/jwt_checking_tool/blob/main/Utility/decoder.go"
click node_verify "https://github.com/alif10151/jwt_checking_tool/blob/main/Utility/verify.go"
click node_schema "https://github.com/alif10151/jwt_checking_tool/blob/main/skeletons/jwt_skeletons.go"
click node_clientui "https://github.com/alif10151/jwt_checking_tool/blob/main/client/index.html"

classDef toneNeutral fill:#f8fafc,stroke:#334155,stroke-width:1.5px,color:#0f172a
classDef toneBlue fill:#dbeafe,stroke:#2563eb,stroke-width:1.5px,color:#172554
classDef toneAmber fill:#fef3c7,stroke:#d97706,stroke-width:1.5px,color:#78350f
classDef toneMint fill:#dcfce7,stroke:#16a34a,stroke-width:1.5px,color:#14532d
classDef toneRose fill:#ffe4e6,stroke:#e11d48,stroke-width:1.5px,color:#881337
classDef toneIndigo fill:#e0e7ff,stroke:#4f46e5,stroke-width:1.5px,color:#312e81
classDef toneTeal fill:#ccfbf1,stroke:#0f766e,stroke-width:1.5px,color:#134e4a
class node_clientui toneBlue
class node_main,node_router,node_handlers,node_createjwt,node_cors,node_utils,node_decoder,node_verify,node_schema toneAmber
```

## Components

### Client

Browser UI surface

- [Browser UI](https://github.com/alif10151/jwt_checking_tool/blob/main/client/index.html): static client · Single-page HTML interface for token input and results · `client/index.html`

### Go Service

HTTP server and JWT processing

- [main.go](https://github.com/alif10151/jwt_checking_tool/blob/main/main.go): entrypoint · Starts the Go server and wires routes · `main.go`
- **HTTP server**: routing · Serves the UI and exposes API endpoints
- [Handlers](https://github.com/alif10151/jwt_checking_tool/tree/main/handlers): http layer · Request parsing, CORS, and response writing · `handlers`
- [Create JWT](https://github.com/alif10151/jwt_checking_tool/blob/main/handlers/create_jwt.go): endpoint · Builds or signs JWTs from request input · `handlers/create_jwt.go`
- [CORS](https://github.com/alif10151/jwt_checking_tool/blob/main/handlers/cors.go): middleware · Cross-origin access handling · `handlers/cors.go`
- [JWT utils](https://github.com/alif10151/jwt_checking_tool/tree/main/Utility): core logic · Token decode and verify operations · `Utility`
- [Decode](https://github.com/alif10151/jwt_checking_tool/blob/main/Utility/decoder.go): parser · Parses token structure and claims · `Utility/decoder.go`
- [Verify](https://github.com/alif10151/jwt_checking_tool/blob/main/Utility/verify.go): signature · Checks token signature and validity · `Utility/verify.go`
- [Skeletons](https://github.com/alif10151/jwt_checking_tool/blob/main/skeletons/jwt_skeletons.go): shared schema · Reusable JWT response and example shapes · `skeletons/jwt_skeletons.go`

## Connections

- Browser UI → Handlers: JWT requests · Browser submits token and secret for processing
- main.go → HTTP server: boots · Application entrypoint starts the HTTP server
- HTTP server → Browser UI: serves · Server returns the static browser interface
- HTTP server → Handlers: dispatches · Routes API calls into request handlers
- Handlers → CORS: applies · Handlers use CORS support for browser access
- Handlers → Create JWT: creates · Handler path for signing or building JWTs
- Handlers → JWT utils: calls · Handlers delegate JWT work to utility layer
- JWT utils → Decode: decodes · Token parsing and claim extraction
- JWT utils → Verify: verifies · Signature and validity checks
- Handlers → Skeletons: shapes · Handlers format responses using shared JWT structures
- Skeletons → Browser UI: renders · Structured results are presented in the UI