Sim Config reference
Sim Config is the durable policy for one session. Edits remain local to the browser until Save Changes succeeds. Runtime overrides on Session Overview take precedence and are intentionally separate.
Current controls
| Section | Fields | Effect |
|---|---|---|
| Default behaviour | Auto-acknowledge new orders, Auto-accept cancel requests, Auto-accept cancel/replace, Reject all inbound orders | Sets persisted behaviour for the matching message types. Reject all inbound orders is a kill switch that overrides the other per-order behaviour. |
| Probability | Accept percent, Error percent | Error percent is evaluated first and emits BusinessMessageReject. For the remainder, Accept percent selects acceptance; a miss produces an execution-report rejection. Values are stored as 0 to 1 and edited as 0 to 100 percent. |
| Timing | Response time (ms), Fill count, Fill stagger (ms), Fill time (ms), Message rate cap (msg/s) | Each range is a uniform random draw per order. Response time delays acknowledgement, fill count sets fills per order, fill stagger spaces fills, and fill time delays the first fill. A message-rate value of 0 is ungated. |
| Reject pool | Code, text, weight | Selects a weighted OrdRejReason (103) when a rejection occurs. Weights are relative; a row with weight 0 is never selected. |
| FIX dictionary | Data dictionary | Uses the selected compatible dictionary in the QuickFIX/n engine for validation and repeating groups. An empty selection uses the session BeginString default. |
| Custom tags | Tag and value | Appends fields to generated outbound business messages without overwriting existing engine fields. Tags must be positive, unique, and cannot be FIX header or trailer fields. |
| Instrument identification | Allowed SecurityIDSource codes | Controls which source codes are accepted for instrument matching. |
| Rules | Enabled, priority, conditions, action | Evaluates enabled rules in ascending priority. The first matching rule wins before any probability draw. |
| Instrument overrides | SecurityIDSource and SecurityID, optional fields | Persists a per-instrument delta over the session baseline. |
| Wire mode | Aggregated, Separate | Aggregated emits one parent report; Separate emits one report per route with its own OrderID. |
| Default route and Instrument routing | Broker slices | Uses the default when no (SecurityIDSource, SecurityID) rule matches. Populated routes must use existing brokers and total exactly 100 percent. |
| Broker overrides | Broker and optional fields | Persists per-broker behaviour, probability, and timing deltas for routed slices. |
Effective configuration
The session baseline is the starting point. Instrument and broker overrides then supply only the fields they set. Global Settings → Override precedence selects whether an instrument-set or broker-set value wins when both set the same field. A matching Sim Config rule is applied after those layers, before probability selection.
Runtime overrides on Session Overview take precedence over the saved values they cover. The Sim Config screen marks those saved behaviour fields as Overridden live. Saving changes the fallback value, not the active runtime result, until the live override is cleared.
Removing an allowed SecurityIDSource can leave instrument overrides without a valid source. If Global Settings → Remove orphaned overrides on save is enabled, Sim Config blocks the save and asks whether to drop those overrides. If it is disabled, the save continues and the overrides remain marked stale.
Routing
Routing configuration shapes the automatic decision used by normal and manual routing. See Multi-broker routing for pending orders, timeout behaviour, and operator application.
Safe editing sequence
- Record the current configuration.
- Change one scenario dimension.
- Save and wait for success.
- Clear conflicting runtime overrides.
- Send a uniquely identified order.
- Verify both blotters and the resulting order state.
A saved configuration does not prove it is the active behaviour. Runtime overrides, instrument overrides, matching rules, and broker overrides can all narrow or replace parts of the baseline.
Updated 2026-09-10 · Edit on GitHub