Everyone in our space keeps repeating the same mantra lately: “Move everything to S2S.” Postbacks, conversion APIs, cookieless attribution – if you listened only to conference panels, you’d think cookie-based tracking is already a relic from another era.
It isn’t.
First-party cookies are very much alive. They sit at the heart of most serious first-party data strategies and, when used correctly, still solve problems S2S cannot touch. At the same time, S2S is obviously the new default for robust conversion attribution in affiliate programs – more resilient to ad blockers, less dependent on browser quirks, and easier to position as privacy-friendly.
If you run a casino affiliate program or oversee a portfolio of brands, treating cookies as something you can just “rip out and modernize” is a bad idea. There are specific situations where cookie-based tracking – especially first-party cookies – still gives you leverage that pure S2S simply doesn’t.
Let’s walk through them like adults who actually have to hit numbers, not just win architecture debates.
Cookie tracking vs S2S in casino affiliate programs
Most modern affiliate setups blend two layers: client-side tracking (scripts, pixels, cookies, usually first-party) and server-to-server postbacks between the casino platform and the affiliate system. S2S tends to win on resilience and accuracy when it’s done right. Cookies win on immediacy, context, and ease of deployment.
The trade-offs look more realistic when you strip away the buzzwords and just compare them side by side.
| Dimension | S2S tracking (postbacks) | Cookie-based tracking (primarily first-party) |
|---|---|---|
| Dependency on browser | Low – works even if cookies are blocked or cleared | High – relies on browser allowing cookies or at least basic client-side scripts |
| Implementation effort | Higher – requires backend integration, QA, and dev cycles | Lower – pixels/tags can be deployed via tag manager or CMS |
| Data granularity pre-conversion | Limited – mostly server-side events (reg, FTD, deposits) | Rich – page views, funnels, scroll depth, button clicks, on-site behavior |
| Real-time debugging | Slower – needs logs, dev tools, cross-team coordination | Immediate – you can test in the browser and inspect cookies / network calls live |
| Resilience to advertiser mistakes | Vulnerable when postbacks are misconfigured or disabled | More autonomous – runs in the browser regardless of backend forgetfulness |
| Privacy and regulation posture | Easier to present as privacy-friendly if you’re careful with identifiers | Needs explicit consent and careful handling, but first-party usage is still perfectly viable |
The trick isn’t asking “cookies or S2S?” It’s asking “where do cookies still give me a clearer, faster, or safer handle on reality than S2S alone?”
There are at least five scenarios where my answer is still: use cookies, or at least keep them firmly in the mix.
1. Fast campaign launches and MVP testing
In the ideal world, every integration is pristine. Fully S2S, modeled events, signed click IDs, neatly versioned environments. In the real world, you sometimes need to launch a new GEO, a new brand, or a seasonal casino promo next week. Not after two sprints and three rounds of QA.
For those “move now, refine later” situations, cookie-based tracking is still the fastest tool on the table.
When we’re testing a new market, my priority is speed of feedback, not architectural purity. A simple client-side setup can start collecting directional data in hours. You drop a tracking script, set a first-party cookie on the funnel, tag outbound links with click IDs, and fire lightweight conversion events on things like “registration started,” “bonus page reached,” or “KYC form opened.”
That’s all before the product team even finalizes the S2S mapping of registration, KYC, FTD, and NGR stages.
The trade-off is clearer if you look at typical launch questions.
| Question in a launch meeting | S2S-only reality | Cookie-assisted reality |
|---|---|---|
| “Can we go live in 3 days?” | Only if devs have bandwidth and endpoints are ready | Yes with a client-side setup; S2S can follow as the canonical layer |
| “Can we A/B test our hero banner from day one?” | Depends on product’s experimentation framework | Possible immediately via cookie-driven split logic on the front end |
| “How fast can we see where users drop off pre-reg?” | Needs extra logging and a backend release | Visible almost instantly via client-side events and cookie-backed sessions |
To be frank, insisting on S2S-first for every little test slows you down more than it protects you. I’d rather ship a carefully implemented first-party cookie solution, learn quickly, and then harden the path with S2S once the experiment proves itself.
2. On-site behavior, funnels, and UX optimization
S2S is brilliant at telling you what happened in terms of transactions. It’s terrible at explaining why those transactions did or did not happen.
If you rely on postbacks alone, you see that an affiliate sent 1,000 clicks and 42 FTDs. Useful, sure. But completely blind to what users did between landing and depositing. That “dark funnel” is where a frightening amount of revenue leaks.
Cookies – specifically first-party cookies on your own domains – are still the simplest way to illuminate that space.
On a real casino funnel, I care about questions like:
- Which review layout keeps players exploring instead of bouncing?
- Are people reading our bonus terms or skipping them and leaving?
- How many users tap “Play now” on mobile and then hesitate on KYC?
A pure S2S setup simply doesn’t see any of that nuance. It only sees server-side end states.
The division of labor looks like this.
| Operator question | What cookie-level data can show | What pure S2S completely misses |
|---|---|---|
| “Why is traffic from this top affiliate weak?” | Session length, scroll depth, exit pages | Only sees fewer regs / FTDs, no idea where the funnel failed |
| “Is our bonus explanation working?” | Clicks on terms, re-visits to bonus page | Sees only whether a reg or deposit happened, not the perception issues |
| “Is the brand selector confusing users?” | Repeated toggling, back-and-forth, rage clicks | Sees only the final brand that got the conversion |
It’s frustrating watching teams obsess over whether last-click attribution is fairly allocated while completely ignoring the fact that 80 percent of users never reach the registration form. That’s not an attribution problem. That’s a UX and funnel problem, and that is firmly in cookie territory.
If I had to pick one place where cookies are not just “still helpful” but genuinely “better,” this is it.
3. Content-heavy SEO flows and long consideration journeys
Casino and betting acquisition is increasingly content-led in mature markets. Users read comparison pieces, scan bonus breakdowns, check payment speed, maybe look at license details. They might click out once, come back via brand search, then finally convert days later.
S2S tracking at the operator level only sees the part of the journey that happens on the operator’s platform. Affiliate software often only sees the outbound click and the eventual conversion. The rich middle layer – how players behave inside your own content ecosystem – belongs largely to first-party cookies and client-side tracking.
A first-party cookie on your casino review or comparison site can do something S2S can’t: remember what that user cared about before they ever set foot on the operator’s domain.
You can log that a user:
- Spent time on high-roller table content versus casual slots.
- Filtered explicitly for fast withdrawals or crypto payments.
- Returned three times to the same brand page before finally clicking out.
By the time the S2S postback tells you “this became an FTD,” your cookie-level history already has a pretty solid idea of which segment this player might belong to.
The contrast per journey stage is stark.
| Journey stage | What S2S sees | What first-party cookies can remember |
|---|---|---|
| Browsing reviews | Nothing | Pages viewed, filters used, time spent on key sections |
| Comparing brands | Maybe the outbound click only | Which brands were compared, in what order, and how often |
| Returning a few days later | Only the eventual registration | Full session history tied together by a first-party cookie ID |
| Converting (reg, FTD, NGR over time) | Postback events and revenue | Joined with pre-click behavior for better cohort and intent analysis |
Have you actually considered what you lose when you strip cookies out of a content-heavy SEO strategy and lean almost entirely on operator-side S2S signals? You preserve attribution but surrender most of your ability to shape and understand intent before handoff.
For casino groups that own both content properties and direct brands, leaning on first-party cookies to own that “middle of the journey” is still a real competitive advantage.
4. Resilience and backup when integrations fail
Everyone loves to say S2S is more reliable than cookies. And yes, when it’s configured correctly, it generally is. The problem is that S2S tends to fail quietly when something is misconfigured.
A typo in a postback URL, a missing token after a platform upgrade, a new event that never got mapped – each of these can wipe out attribution for hours or days. In iGaming, that translates directly into real money, uncomfortable calls with affiliates, and a lot of manual reconstruction.
Cookies, especially when written by your own tracking layer on first load, are more autonomous. If the browser loads the page, the cookie logic can run, whether or not the backend remembered to fire a postback.
The analogy I like is a flight data recorder. It doesn’t replace good navigation, but when something goes wrong, you’re very happy it exists.
A lean browser-side log can record:
- Click IDs and sub-IDs at the moment of click-through.
- Basic session and device context.
- Timestamps for key funnel events before handoff.
If S2S breaks for a period, you at least have a forensic trail. You probably won’t rebuild every single FTD perfectly, but you can still estimate what happened and have a more honest conversation with partners.
The operational contrast is pretty clear.
| Incident | S2S-only setup | Hybrid with cookies as backup |
|---|---|---|
| Broken postback for 3 days | No conversions logged; heated disputes with affiliates | Browser-side logs show affected traffic; impact can be estimated |
| Mis-mapped event (reg counted as deposit) | Distorted CPL/CPA economics; late discovery | Front-end events show normal patterns; discrepancy spotted faster |
| Migration to a new casino platform | Risk of losing continuity if mapping isn’t perfect | First-party cookies preserve continuity in your own ecosystem |
Here’s the bottom line: the more you centralize your faith in S2S as the only source of truth, the more any silent failure becomes catastrophic. Cookies give you a second narrative, which is invaluable when revenue and relationships are involved.
5. Multi-program affiliate portfolios and cross-stack consistency
Most serious casino affiliates don’t work with a single operator or one pristine platform. They promote dozens. Some support excellent S2S integrations, some are stuck on old pixels, some live on networks where you can’t see much of anything except end-of-month summary numbers.
If you try to normalize performance purely based on whatever tracking each operator provides, you end up comparing apples to oranges to mystery fruit.
Maintaining your own cookie-based, first-party tracking at the affiliate or aggregator layer is still one of the cleanest ways to standardize outbound click and engagement data across a chaotic ecosystem.
Imagine a high-traffic casino comparison site working with three brands:
- Brand A has strong S2S tracking and granular reporting.
- Brand B uses a dated pixel and clunky CSV exports.
- Brand C sits on a network that abstracts almost everything.
You still need to answer very basic questions:
- Which placements on your pages generate the highest FTD-per-click overall?
- Which GEOs respond better to low-wagering offers versus big headline bonuses?
- Which traffic sources feeding into your site are actually worth scaling?
If you rely entirely on each brand’s reporting, you inherit three different definitions of “click,” “session,” and in some cases “FTD.”
With your own cookie-based tracking, you can at least standardize the top of the funnel: who clicked what, from where, using which device, after seeing which content.
| Perspective | Without your own cookie layer | With your own cookie layer |
|---|---|---|
| Measuring outbound CTR and quality | Fragmented, tied to each operator’s reporting quirks | Unified, first-party view of clicks, engagement, and pre-click intent |
| Evaluating placements and layouts | Dependent on partner dashboards | Direct measurement on your site, comparable across all brands |
| Testing new niches or languages | Slowed by waiting for every operator’s integration | Driven by your own front-end data; operators can be plugged in later |
Have you noticed how much strategic visibility you’ve quietly outsourced to operators and networks that don’t necessarily share your priorities? Keeping cookie-based tracking under your control is one way to refuse that blindness.
How I actually combine S2S and cookies now?
In practice, the best setups in 2025 are unapologetically hybrid.
S2S is the canonical layer for money and official attribution. Registrations, FTDs, deposits, withdrawals, NGR – all mapped via secure postbacks, with strong IDs and consistency checks. That’s the layer you reconcile accounts with and pay affiliates from.
Cookies – specifically first-party cookies – are the behavioral and resilience layer. They capture on-site journeys, friction points, and preferences. They give you continuity across content properties and multiple brands. They act as your “black box recorder” when integrations wobble.
The broader industry is clearly moving toward first-party data, consent-driven tracking, and API-based integrations instead of blind third-party cookies. That direction isn’t changing.
But being “modern” doesn’t mean you throw away every browser-side tool you have.
Use S2S where it shines: clean attribution, platform-to-platform communication, resilience against browser changes. Use cookies where only the browser has the vantage point: pre-conversion behavior, real-time UX insight, fast experimentation, and cross-stack consistency.
The interesting question for any seasoned casino operator right now isn’t whether S2S is the future. It’s whether you’ve quietly weakened your own visibility and agility in the rush to be “cookieless,” and how much that strategic blindness is really costing your affiliate program.
