# steprs.dev: Full context

> Client-side STEP triage. Zero upload. No machine crashes.. Run your STEP files through an instant, local pre-flight check before opening heavy CAM software. Verify tool reach, Z-axis stack clearance, and workholding fits in 60 milliseconds. 100% inside your browser worker via Rust WebAssembly.

## Product summary

steprs.dev is for machinists and hobby CNC users who want a fast answer to "can I make this?" before opening Fusion, Mastercam, or Carbide Create. Client-side Rust WASM parser (Apache-2.0). No cloud upload.

### Capabilities

- Pre-Flight: Pick your machine, vise, and tool crib. Flags travel fit, Z clearance, drill reach, shank collision, flat-bottom blind holes, and undercuts.
- Header: AP protocol, units, assembly flags from the STEP header.
- Holes: Cylindrical features with nearest catalog drill or endmill (±0.15 mm).
- Stock: Part envelope with allowance, snapped to common billet sizes.
- 3D preview with floor-aligned framing.
- AAG export: Face adjacency with concave/convex counts — topology only, no coordinates.

### How it works

- Rust WASM parser in a Web Worker — main thread stays free
- Single pass: ingest, topology, holes, stock, optional mesh
- Files stay on your machine; no upload path

### Pre-Flight rules (client-side)

Machine travel fit, vise jaw opening, Z-stack clearance (vise + part + tool stickout), drill reach vs bore depth, pocket depth vs flute length (shank collision), flat-bottom blind hole flags, undercut/5-axis warnings, machinability score, starting RPM/feed from SFM baselines.

### Engine pipeline

1. **Ingest**: DATA scan, entity parse, adaptive arena
2. **Topology**: Face IR + edge adjacency
3. **Part analysis**: Units, envelope, holes, pockets, slots, undercuts
4. **AAG**: Joshi–Chang concave/convex classification
5. **Mesh**: Fan triangulation for preview (capped)

### WASM API

```javascript
const parser = new StepParser();
parser.parse(bytes);
parser.parseQuotingOnly(bytes);
parser.cancel();
```

### HTTP API v1 (example fixtures only)

| Endpoint | Returns |
|----------|---------|
| GET /api/v1/fixtures | Catalog |
| GET /api/v1/fixtures/{id}/handoff | Machining facts + compact AAG |

### Keywords

STEP file checker, CAM pre-flight, CNC pre-flight, STEP holes, stock sizing CNC, STEP parser browser, Shapeoko STEP, hobby CNC, machinist tools, tool crib, machine envelope, ISO 10303, STEP units check, billet sizing, client-side STEP, open core CAD, machinability score, WASM STEP parser, local CAD checker, no upload STEP

### Links

- https://steprs.dev/
- https://steprs.dev/faq
- https://github.com/vladimir-io/steprs-dev