Alpaca — Rate Limits & Resilience

Alpaca's APIs are rate-limited and occasionally flaky under load. Any client that does more than a handful of calls — especially bulk jobs, backfills, and reconciliation sweeps — needs disciplined retry, backoff, and concurrency control. These patterns are transport-level and apply in any language.

Read alpaca-broker-integration first.

1. Rate-limit headers — read them on every response

Alpaca returns standard headers:

Parse them on every response, not just on errors. Two uses:

• Proactive: slow down as Remaining falls toward zero, rather than waiting to be throttled. Any warning threshold you pick is your own starting point, derived from Limit — Alpaca publishes none.
• Reactive: on 429, use Reset to wait exactly until the window opens.