WebSocket and REST testing for volatility surfaces.

The streaming API bootstraps consumers with a full surface snapshot, then sends compact patches as quotes, fits, risk metrics, and fixed-tenor rows change. The browser dashboard uses this same contract for live market monitoring.

• svi_surface_snapshot and svi_surface_patch for calibrated surface state.
• smile_levels_snapshot and patch messages for bid, ask, trade, and venue-level quote overlays.
• svi_tenor_snapshot and patches for fixed-tenor term-structure outputs.
• Fit-status, risk-reversal, fly, and diagnostic messages around each calibration cycle.

REST behavior remains under testing. Endpoint names, authentication, limits and resource availability can change and are supplied directly to an approved evaluator.

• Current surface and smile state are candidate evaluation resources.
• Fixed-tenor and fit-diagnostic responses remain testing behavior.
• Consumers must use the endpoint names and schema version supplied with their evaluation access.

Payloads are JSON and include the active currency where available. Consumers should treat snapshots as authoritative bootstrap state and patches as sparse updates.

{
  "type": "svi_surface_snapshot",
  "schemaVersion": 1,
  "ccy": "BTC",
  "smiles": [{
    "expiry": 1778990400000,
    "label": "17MAY26",
    "x_axis": { "kind": "log_moneyness", "values": [-0.3, 0, 0.3] },
    "vol": [42.1, 34.8, 38.6],
    "risk_reversals": { "RR25": -5.57 },
    "flies": { "FLY25": 1.37 }
  }]
}

The same diagnostics shown in the dashboard can be published for testing: through-fit cells, skew and fly term structures, fit error state, active smile count, and fixed-tenor rows.

API evaluation is request based. These entries describe client-facing implementation changes without asserting a stable open REST contract.

• May 16, 2026: Added request-based WebSocket and REST API testing documentation, including current-state REST resource families.
• May 16, 2026: Documented fixed-tenor WebSocket outputs through svi_tenor_snapshot and tenor patches, plus evaluator-specific REST testing.
• May 16, 2026: Added multi-currency testing language for BTC, ETH, and additional currencies under review.
• May 16, 2026: Added dashboard consumer support for smile_levels_snapshot_batch messages.
• May 16, 2026: Added dashboard consumer handling for currency-selection messages and outgoing select_currency requests.
• May 16, 2026: Broadened accepted fly and butterfly payload aliases, including fly_values, butterfly_values, bf, and rr_fly.
• May 16, 2026: Broadened accepted fly node payload aliases, including fly_nodes, butterfly_nodes, and camelCase node-point variants.
• May 16, 2026: Restored fly diagnostics when scalar FLYxx values are absent by deriving them from matching put, call, and ATM node vols.

Email info@derivasys.com with the intended use case, currency scope, preferred protocol, and whether fixed-tenor outputs are required. Test access can then be configured with the appropriate endpoint, key, and usage expectations.