Sub-ID (s1–s5)
A sub-ID is an optional label an affiliate appends to a tracking link to segment their traffic. LimeliJourney supports five (s1 through s5); they ride along on every click and are copied onto the conversions that click produces, so you can see which source within an affiliate performs.
A sub-ID is a free-form label that segments an affiliate's traffic. Affiliates (or you) append s1 through s5 to a tracking link, and those values travel with the click and land on the resulting conversion. The point is granularity: instead of seeing "Affiliate #34 sent 5,000 clicks," you see which of their sources those clicks came from, and which ones actually convert.
The s1 convention: traffic source
By convention, s1 is the traffic-source dimension — the value the platform groups sub-ID reporting by, and the one you can block or re-price. Use stable, reusable labels: s1=newsletter, s1=facebook, s1=push_network_7. The classic mistake is putting a unique value in s1 (a timestamp or a click ID); that produces thousands of one-click rows and makes the report useless. s2–s5 are free passthrough slots for finer detail — placement, ad set, keyword.
A worked example
An affiliate promotes your offer from three places and tags each:
...&s1=newsletter...&s1=facebook...&s1=native_ads
A month later the sub-ID report shows newsletter at a $0.90 EPC, facebook at $0.35, and native_ads at $0.02 on 8,000 clicks and near-zero conversions. That last row is the tell: high clicks, no conversions — likely junk or fraud. You do not have to pause the whole affiliate. You can block just s1=native_ads on the campaign, or set a lower payout for it, and leave the profitable sources flowing.
Reading traffic quality
Sub-IDs are the primary lens for traffic quality. A source with lots of clicks and almost no conversions, or a sudden click spike with flat conversions, is a red flag. Because the value is stamped onto the click, frozen economics mean a payout override you set today applies only to future traffic from that source.
How this works in LimeliJourney
In LimeliJourney's tracking, you pre-fill sub-IDs when generating a link (the Sub-ids section on the Tracking Links page), or affiliates append their own. Open an affiliate and go to the Sub-IDs tab to see their traffic broken down by s1 — clicks, conversions, and money per source. To act on a bad source, use the campaign's Caps & Limits tab: Blocked Sub-IDs stops that source (clicks are redirected to a fallback), while Per-Sub-ID Payouts re-prices it instead. Sub-ID values also appear as columns on the Clicks and Conversions reports, and LimeliChat can break any affiliate's traffic down by sub-ID on request.