BSL Operations

BSL is designed for low-latency professional flow, so operations should expose pressure early and keep recovery deterministic.

Session Controls

Control	Endpoint
Current limits	GET /api/v1/bsl/limits
Session state	GET /api/v1/bsl/sessions
Cancel-on-disconnect	POST /api/v1/bsl/sessions/cancel-on-disconnect
Quote obligations	GET /api/v1/bsl/markets/{marketId}/quote-obligations

Cancel-on-disconnect is a production safety control, not a convenience helper. Operations should define the session timeout, heartbeat expectations, and account-level stale-order policy before enabling high-rate quoting.

Backpressure Policy

BSL must reject early when the venue cannot keep latency bounded. The expected client-facing codes are:

Code	Operational cause
SHARD_BUSY	Market shard cannot accept more work without queue aging.
QUEUE_LIMIT	Ingress lane, backlog, or concurrency limit reached.
RISK_CREDIT_LIMIT	Credit or exposure reservation denied.
KILL_SWITCH	Account, market, or venue kill-switch is active.
MARKET_HALTED	Market lifecycle gate blocked trading.

For professional clients this is a feature. A fast reject lets the strategy cancel, widen, or reroute immediately.

Observability

Monitor these dimensions per account, market, and shard:

Metric family	Why it matters
BSL request latency by result mode	Separates ACK, DURABLE, and FULL behavior.
x-bsl-* timing breakdowns	Locates latency in auth, risk, queue, engine, durability, or edge.
Reject code counts	Shows whether clients hit queue, risk, market, or auth limits.
Per-shard exposure and locked credit	Protects the venue while enabling multi-market quoting.
Release lag for credit and order reservations	Finds stale locks that harm quoting capacity.
Execution stream gap-fill rate	Detects stream disconnects or client lag.

Deployment Checks

Before advertising BSL to a client:

• GET /api/v1/bsl/limits returns x-bsl-contract: bsl-order-entry-v1.
• POST /api/v1/bsl/orders/batch returns a bsl envelope on both success and reject paths.
• POST /api/v1/ws/token tokens work immediately on /api/v1/bsl/accounts/{account}/executions.
• The private BSL WebSocket emits monotonic execution seq values.
• Cancel-on-disconnect is tested against a resting-order account.
• The client has documented behavior for SHARD_BUSY, QUEUE_LIMIT, RISK_CREDIT_LIMIT, KILL_SWITCH, and MARKET_HALTED.