Supply Path Optimization (SPO) has moved from a nice-to-have to a must-have for any serious programmatic buyer. Yet many teams still treat it as a one-time exercise rather than an ongoing discipline.
What Is SPO, Really?
At its core, SPO is about choosing the most efficient and transparent path between your DSP and a publisher's ad inventory. Every impression you buy travels through a chain of intermediaries — SSPs, exchanges, resellers — and each one takes a cut. The goal is to minimize hops, reduce fees, and improve signal quality.
"The best SPO strategies don't just save money — they improve performance by ensuring your bids reach the right inventory through the cleanest paths."
Step 1: Audit Your Current Supply Paths
Pull a supply path report from your DSP. Most tier-1 platforms (DV360, The Trade Desk, Xandr) offer this. Look for:
- Duplicate paths to the same publisher (you're bidding against yourself)
- Resellers with high take rates and low win rates
- SSPs where you consistently lose auctions despite competitive bids
- Inventory sources with high invalid traffic (IVT) rates
Step 2: Prioritize Direct Paths
Direct paths (publisher → SSP → DSP) typically offer better pricing, fresher signals, and higher match rates. Use ads.txt and sellers.json to verify which SSPs have direct relationships with your target publishers.
Step 3: Build an Inclusion List
Rather than trying to block bad supply (whack-a-mole), build an inclusion list of vetted supply paths. Start with 10-15 high-quality SSPs and expand from there based on performance data.
Conclusion
SPO is not a one-time project. It requires ongoing monitoring, regular audits, and a willingness to cut underperforming supply sources. The payoff? Lower CPMs, better win rates, and more transparent media buying.
