🃏 Every DFS player has rules they’d swear by. I had a lot of them.
Last NFL season said some were wrong. Problem was, I didn’t know which ones.
So I put them all on trial 👇
#NFLDFS #DFS #DraftKings https://x.com/i/article/2115254060035010560
The 5 playbooks that reset my NFL DFS process
My DMs have turned into a help desk. What's your process? What tools do you use? What's this CODEX you keep mentioning, and how do you actually use it?
Fair questions. Here's the long answer.
Start with the honest part. My 2025 NFL DFS season was rough. I ran bad, no doubt. I missed a couple of huge binks by an inch, the kind you replay in your head all Monday.
But I also played bad. Showdown was the worst of it. Among other issues, my lineups were way more duped than I wanted, and I usually found out when the payout got split.
The process was its own problem. I was burning every Sunday morning crunching numbers in the same tools the big mainstream sites sell to everyone. Nothing against them: those tools are often as good as the person using them. At the same time, it was lots of hours for the same outputs as a sizable portion of the field.
I didn't want to burn it all down. I felt strongly about a lot of my rules, and some of them were right. What I needed was a way to check them against something other than my memory of the slates I won.
That's when I stumbled on the DFS Army CODEX, written by Kevin Alan (@ffootballgeek). It was the push I needed to reset properly. Today my process is more robust, and it takes a lot less of my time.
What the CODEX actually is
Five research reports built from real contest results. Two cover main slates, two cover Showdown, and one studies how the sharks build.
Three of them show you what wins. Two show you how to build it in an optimizer. None of them tell you who to play on Sunday, which is exactly why they're useful.
Here's what each one changed for me.
01 · Cracking the DFS Code (main slate)
The foundation. They took apart a big archive of large-field GPP results: how winning lineups stack, how much chalk they carry, where they punt, and which field habits quietly lose money.
I came out of it with numbers where I used to have vibes. How often I want a secondary stack across a 150-max, for one. I was eyeballing it before.
Another one: cumulative ownership bands that move with field size. A massive tournament and a small one shouldn't get the same ownership ceiling, and I was using my guts on those numbers.
02 · The Showdown Codex
350 real Showdown contests broken down into game scripts. Showdown looks easy. One game, six spots. That's why most of the field plays it badly.
Given my dupe problem, this one hit home. The lesson was salary. I knew leaving money on the table was a way to get unique. I just wasn't leaving nearly enough. I was building close to the cap and calling the lineup different because of one pivot.
03 · How to Stack Showdowns
Playbook 2 shows what wins. This one shows how to build it, button by button, with optimizer settings and stacking rules backtested on millions of lineups against real contests.
I already had a huge library of my own Showdown rules. This was the audit. Some held up. Some got rewritten. A few I'd been carrying around for ages went straight in the bin.
04 · The Main Slate Settings
The biggest project in the set: 150+ setting combinations, close to 10 million lineups, 62 NFL Sundays rebuilt across four seasons and scored against 404 real tournaments. It ends with one champion build.
The author put it all together to provide his suggested settings each Sunday. I also compared it with my own and made many tweaks. Spoiler: I didn't blindly re-use it but applied what fits my play style and contests.
05 · The Shark Study
1,120 verified 150-max sets from the 18 highest-volume players, over two seasons. This is the one I couldn't put down, because these are the names I keep seeing at the top of the leaderboard.
Spoiler: no two of them build the same way. Their styles are all over the place. What they share is consistency. There's more than one way to win in DFS. Each of them picked one and stuck with it.
Where it got interesting: plugging it into AI
Reading five playbooks is one thing. Running them every slate is another.
I broke down optimizers vs sims vs AI in another thread: https://x.com/TintinPoker/status/2102447202098438348
Short version: an optimizer does what it's told, a sim tells you what might happen, and generative AI can hold an entire rulebook in its head and argue with you about it.
Here's how I set it up.
1️⃣ One project per format. I built a dedicated project in Claude for NFL Classic and another for Showdown. Completely different format; I don't want to mix concepts.
2️⃣ Seed it with the playbooks and my own rulebook. The CODEX findings went in as the evidence. My rules went in as the thing being tested.
3️⃣ Make it argue. The first job was reconciliation: go through every rule and sort it. Supported by the data, contradicted by it, or no evidence either way. That's where the keep, rewrite, bin list came from.
4️⃣ Every rule gets a number. "More secondary stacks" can't be audited. "Secondary stack in X% of lineups" can. Same for salary left on the table, cumulative ownership by field size, and exposure in every salary range. You can also use this to audit your lineups before lock.
5️⃣ The most important step: Close the loop every week. The slate goes in (projections, ownership, odds, analyst notes), lineups come out against the rules, and after the slate we check what the winners did that we didn't. The project gets a little sharper every Sunday.
This is also where my Sunday mornings came back. The rules are already set, so the time goes into reading the slate instead of fighting the tools.
Then we started building on top of it. Best example so far is a Showdown dupe predictor, the tool I wish I'd had last season. Before I enter, it estimates how likely each lineup is to be shared, based on the ownership of every player in it, the captain, and how much salary is left, correlation, etc. Showdown has so few combinations that a lineup that looks contrarian can be sitting in plenty of other entries. Now I find out before lock instead of at payout.
If you want to build your own:
👉 Start with your rules, not a blank page. You know more than you think. You just haven't tested it.
👉 Ask the AI to prove you wrong, not to agree with you.
👉 Audit your last 150-max against the benchmarks. Stack rate, chalk count, salary used. The gap will surprise you.
👉 Pick one shark from playbook 5 whose style fits your time and bankroll. Blending five styles gets you mush.
👉 Use the data as a sim sanity check. If your sim's top lineups look nothing like historical winners, question the inputs before you trust the output.
The playbook I'm still waiting for
The CODEX covers 10+ game main slates and single-game Showdown. Everything in between is guesswork.
And there's a lot of in between. Afternoon-only on Sundays, every single week. Thanksgiving. Christmas. The late-season Saturday slates. Then the playoffs, where the game count keeps shrinking.
We all have assumptions about these slates. It's harder to get unique. Onslaught stacks sim great. But they're assumptions, and I just spent a season learning what untested assumptions cost.
The questions I'd want answered with real data:
🎯 How many players from one game is too many?
🔗 Five from one side plus two run back: does it make money over time, or does it just look great in the sim?
🛡️ Stacking a QB with his own defense: losing, neutral or profitable?
💰 Which salary bands win, and how much do winners leave on the table?
📈 How much chalk do winning lineups carry?
👯 How bad do dupes really get?
@DFSArmy @ffootballgeek, if you're reading, that's the next playbook.
Want the CODEX?
It comes with a DFS Army membership: https://www.dfsarmy.com/pricing?affiliate=178
Code lethuima gets you 10% off.
Affiliate link, I earn a commission if you join. Judge it by this article: I use it every week.
TL;DR
Ran bad and played bad in 2025, mostly in Showdown. I reset my process instead of rebuilding it from zero.
The CODEX gave me data to test my rules against. Kept some, rewrote some, binned some.
Paired with AI, it became a weekly system that takes less time and catches dupes before lock. Short slates are the missing chapter.
Good luck. 🍀
— The Dealer 🃏
#NFL #DFS #NFLDFS #DraftKings #DKNFL #GPP #Showdown #DFSArmy #FantasyFootball #NFLShowdown #DFSStrategy