Overview

Amazon has increased the throttling limits for two primary Merchant Fulfillment API v0 endpoints—getEligibleShippingServices and createShipment. The steady‑state allowance for getEligibleShippingServices has moved from 5 to 6 calls per second, while its burst ceiling grew from 10 to 12 calls. CreateShipment now permits 5 steady calls per second (up from 4) and a burst maximum of 10 calls (up from 8). Sellers who automate large volumes of order fulfillment need to understand these new thresholds to keep their shipping pipelines running without unexpected 429 errors.

Key Points

• Higher steady‑state quota — getEligibleShippingServices can now be invoked up to 6 times each second, giving a modest but useful margin during continuous traffic.
• Expanded burst window — The same endpoint can absorb short‑term spikes of up to 12 calls in a single second, compared with the former limit of 10.
• CreateShipment uplift — CreateShipment’s baseline rate rose to 5 calls per second, and its burst capacity increased to 10 calls, enabling quicker batch shipment creation.
• 429 responses still apply — If a caller exceeds the revised limits, the API will return an HTTP 429 status, so ongoing monitoring remains mandatory.
• Third‑party tools benefit — Order‑management platforms that bundle dozens of shipments per minute will experience fewer “Too Many Requests” interruptions.
• No version migration needed — The changes affect the existing v0 endpoints; developers do not need to switch to a new API version.

How the Throttling Changes Work

1. Quota verification — Every inbound request to either getEligibleShippingServices or createShipment is compared against the new per‑second allowance. For instance, a script that fires 7 requests within one second will now be allowed 6 without penalty; the seventh request will receive a 429 until the next second begins.
2. Burst accommodation — When traffic spikes, the system permits calls up to the newly defined burst ceiling. Example: during a flash‑sale, a seller’s integration may generate 11 simultaneous getEligibleShippingServices calls; the API will accept all 11 because the burst limit is 12, whereas previously only 10 would have succeeded.