A service level agreement is the section of a 3PL contract that turns vague promises into measurable obligations. The common SLA metrics are same-day ship cutoff time, pick-and-pack accuracy percentage, inventory accuracy percentage, and dock-to-stock turnaround. A good SLA also defines the financial consequence when a metric is missed: credits, fee waivers, or termination rights.
How it works in practice
A typical Vertex SLA for an ecommerce brand reads something like: orders placed by 1pm local ship same business day, pick accuracy at or above 99.5%, inventory accuracy at or above 99.0% on cycle counts, and dock-to-stock under 48 hours from arrival on appointment. Each metric has a measurement window (usually monthly), a reporting cadence, and a remediation step if it slips two months in a row. The SLA also defines what does not count: carrier delays, address errors, and acts of God.
Why it matters
Without a written SLA, every operational complaint becomes a he-said-she-said. With one, the conversation moves from “you’re slow” to “you missed the 1pm cutoff on 4.2% of orders last month, here’s the credit.” SLAs are also what enable brands to confidently set customer-facing shipping promises on Shopify product pages.
Common misconceptions
- An SLA is not the same as a target. A target is internal, an SLA is contractual.
- Higher SLAs are not always better. A 99.9% pick accuracy SLA usually means a higher pick fee. Most ecommerce brands are fine at 99.5%.