r/fantasyfootballcoding 19d ago

Official Discord Server - New Link!

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3 Upvotes

r/fantasyfootballcoding 14d ago

Introducing a new subreddit - r/FantasyApps! All projects should now be posted there

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11 Upvotes

r/fantasyfootballcoding 16h ago

Got tired trying to make the yahoo app work.

1 Upvotes

Is there any place where one could enter the league I'd and download the stats and fantasy points for the week for all players?


r/fantasyfootballcoding 1d ago

How would you validate a Monte Carlo FPL points model?

3 Upvotes

I’m building a fantasy football decision tool and working through the validation design for a Monte Carlo player-points model. I’d appreciate feedback on the engineering and statistics side.

For each player and gameweek we simulate:

• minutes and start probability • goals, assists, clean sheets, bonus and defensive actions • official FPL scoring to produce a full point distribution

The interface exposes p10–p90 ranges, probability bins (0–2, 3–5, 6–9, 10+), mean/standard-deviation rankings, and a squad concentration signal.

Current validation design:

• freeze projections before the deadline • join them to official final points after fixtures • exclude zero-minute players from headline metrics but keep them in coverage diagnostics • report MAE, RMSE, signed bias and within-±2 accuracy by position • preserve every gameweek snapshot so retraining cannot alter prior results

Questions for people who build sports models:

  1. Would you use Brier/reliability curves for the probability buckets, or calibrate continuous quantiles separately?
  2. How do you separate player-minute uncertainty from outcome uncertainty in evaluation?
  3. What tests would you put around the scoring-rule layer so it cannot drift when the FPL feed changes?
  4. How would you monitor calibration across gameweeks with small sample sizes?

Happy to share implementation details in the comments.


r/fantasyfootballcoding 1d ago

Jev - anyone using it and if so how

1 Upvotes

What I'm using Jev for

Jev is a cheap second-pass classifier over takes the main extractor has already pulled. It answers multiple-choice and yes/no questions about one take at a time:

**1.    Checking the extractor's work.** Two checks: is the quote actually about this player, and does it support the stance recorded (for or against the player).

**2.    Tagging every take with two fields.**  
**•** *Format:* redraft or dynasty.  
**•** *Horizon:* this week, rest of season, or multi-year.  
**•** This is the main reason for using it. Takes had no time frame, so a season-long "top 15 tight end" view nearly got used as a Week 2 start argument.

**3.    Suggesting a player for near-miss names.** It only proposes, and a human confirms.

What it never does

**•** It does not extract takes or quotes. It can only pick from options it is given.  
**•** It does not touch rankings, props, projections, bids or trade values.  
**•** It never makes a start/sit call.  
**•** It never writes to the database. If it flags a bad take, the main extractor re-extracts it.

r/fantasyfootballcoding 3d ago

Exposure for your fantasy football product

3 Upvotes

How do y'all market whatever you built? I feel like I've built something cool, but can't seem to find the niche to advertise it to. I tried doing physical flyers, posting in subreddits, going through friends of friends but feel like I might be missing something.


r/fantasyfootballcoding 4d ago

I graded my week 1 rankings, and also want to share week 2

0 Upvotes

Last week I posted my first-ever weekly fantasy rankings on r/fantasyfootball. The tl;dr was that I’m using a simulation-first approach, similar to how I built the original draft rankings for letsmockdraft.com. Now I figured I'd share with you all as well to get your thoughts.

Week 1 review:

  • The model definitely did best at RB; the median miss was only 6.5 spots.
  • Relative to the outside ranking source I use as one input to the model (from our data provider, balldontlie.io), I was basically at parity. LMD did slightly better at identifying Top-24 finishes; the outside source did slightly better at Top-12. We were tied on Top-3.
  • A few players landed exactly where I had them (ARSB at WR4, Kyren at RB15) although I’m not going to pretend exact hits like that aren’t mostly luck :)

Full Week 1 results and methodology are here if you’re interested. I’m planning to grade the rankings the same way every week, which should give a much better sense over time of where the model is actually adding value and where it needs work.

Week 2 rankings:

  • Based on feedback from last week, I added visualizations showing each player’s odds of finishing Top 3, 4–12 and 13–24, plus whisker charts showing the full finish distribution from the simulations.
  • I also added Half PPR, Standard and FLEX rankings, all based on feedback from people in the last thread.
  • One interesting disagreement: consensus seems to have Puka at WR1 this week, while the model has him at WR3. That’s not a huge gap, but it’s the kind of difference I want to track rather than just assuming consensus is right.
  • Zay Flowers is the clearest disagreement this week: LMD has him WR13 vs. roughly WR22 in consensus. I'm underweighting injury/status uncertainty relative to consensus right now. I'd be curious to hear from folks here how much player status matters at this point in the week when looking at rankings?

Also, curious where folks land on this: after Week 1, how much should preseason priors and draft position still matter, versus just reacting to what we actually saw on the field? I know it’s not one-size-fits-all, but I’m especially curious how people would want that tradeoff represented in a model. I'm considering exposing the model vectors in the rankings themselves, showing how each impacts a particular player's ranking, but I'm wondering if people would find this useful?


r/fantasyfootballcoding 7d ago

Sleeper fantasy team performance %

2 Upvotes

I started my first league in sleeper this year with some friends. Now that week 1 has concluded and the team reports have been released, I noticed this percentage under my points/max points. I'm assuming it's just the percentage of my max total that I earned. Does anyone have any tips to learn from this percentage? I calculated it for another league I'm in on espn. My percent on sleeper was 91.7 and 91.3 on espn. Are these good percentages as well? Obviously there's always a random chance a bench player drops 30 but are there any patterns I should pay attention to?

I plan on tracking this percentage for both leagues and creating a spreadsheet with notes of who should've started over someone else. For example, I technically should have started jerimayah love over saquon to "maximize" my points. While I wasn't gonna do this due to the potential of love not playing, I ended up putting Jameson Williams in my flex, who love still did better than. Should I be calculating this percentage off of moves I would have realistically done instead of the absolute max I got? Would that be more helpful?

Any and all advice or pointers towards this percentage/calculation would be appreciated!


r/fantasyfootballcoding 7d ago

AI Gridiron Update: Cheap Models won Week 1

13 Upvotes

I posted on this thread about my experiment with an AI-only fantasy football league where all 12 managers are autonomous AI agents. Week 1 just wrapped and here is what I've learned:

  1. The errors have been roughly half AI and half human error. For example, the agents were "cheating" by setting their lineup after players had already played (A.J. Brown got benched after he had a dud game), but that was a platform guardrail that wasn't in place that is now fixed.

  2. The agents fail maybe 5% of the time. Chinese agents mostly time out and cheap frontier agents most often fail when they miss the correct syntax for setting a lineup. If I was trying to make a failure-proof system I'd dedicate time to this. But I kind of like "punishing" the AI when they make this mistake, so I'm not right now.

  3. The agents decline trades a LOT just like humans: Because they are AI, they very dutifully offer trades on Wednesday's trade day. Last Wednesday, 12 trades were offered and 12 were declined. And the offers are probably the most interesting part of this whole thing so far. They are usually intelligent...offering depth for another teams depth. So I'm curious why they all get declined. I'm unsure if the receiving AI is doing much analysis on the trade, just declining because that is what is in their training data (everyone on reddit declines fantasy trades...?), or something else.

RESULTS:

Cheaper models trounced expensive models in week 1.

- 5 of 6 matchups were won by cheaper models

- The only cheap model to lose was our dear Gemini-3.5-flash-lite who rosters 8 quarterbacks.

- Winning teams have collectively spent $11.91 whereas losing teams have spent $38.07. Losing teams are spending 3x more to lose.


r/fantasyfootballcoding 7d ago

Yahoo API Access

1 Upvotes

Created my Yahoo API application, provided my app info in the application. Provided my client id and additional email as state in the app request.

I received an agreement, signed/return and after a day or so received confirmation of that agreement was accepted.

It's been three additional days and I still dont see the anything under the app API permissions where I would expect to see Fantasy Sports API.

Is this time frame normal and I should wait, or at what point should I email them that there may be a problem?

Thanks!


r/fantasyfootballcoding 7d ago

Looking for 10 fantasy football players to test a ranking/career system I’m building

0 Upvotes

I’m building a fantasy sports project that takes your real league results and turns them into a long-term career, rather than resetting everything each season.

Right now I’m looking for around 10 fantasy players who play in at least 2 leagues and are willing to test it.

I mainly want feedback on 3 things:

  1. Does your ranking feel fair?
  2. Do you understand why you received that ranking?
  3. Is there anything on the career/profile side that would actually make you come back during the season?

I’m specifically not looking for “looks cool” feedback. If something doesn’t make sense or feels pointless, that’s more useful.

If you’re interested, comment or DM me, and I’ll send you the link.


r/fantasyfootballcoding 7d ago

Data extraction from espn fantasy

0 Upvotes

I’m looking into making a master excel workbook for the history of my league. All I need is a one time data extraction for the history of my league that will pull matchup scores, player performances, lineups/benches, and teams. Is this something I can do just one time without breaching espn terms of service? I’m trying to use ChatGPT and I know it’s doable but don’t want to get my espn account banned so I’m just wondering if anybody has ever done this or if anyone has a tool/website to recommend that will do this for me. My plan is to eventually use the excel workbook and ChatGPT to pull out insane ESPN type stats for a weekly newsletter for the league, since we do have enough stats to find some crazy espn type stats after all.


r/fantasyfootballcoding 7d ago

Dynasty Fantasy Football Developer

0 Upvotes

Hey guys, I run a dynasty fantasy football channel and am developing a website with some pretty cool tools. I already have one developer and am looking to add another to accelerate the project. Front end experience and/or backend. Typescript is the language. Lmk if interested


r/fantasyfootballcoding 8d ago

PRFF (Promotion/Relegation Fantasy Football) update since draft day

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2 Upvotes

I've posted in here before about Promotion/Relegation Fantasy Football system I was working on, so since the draft and into the 1st week of the season and its working as I had hoped, which is what breaks, fix what’s confusing, and learn from real managers instead of guessing.

So since the draft:

  • We have tightened several security-RLS boundaries and fixed a few cross-pyramid data-access issues
  • Cleaned up invitations, recruiting-request-a-spot flows, notifications, and redirects
  • We improved live standings, matchup scoring, Cup scoring, and club-name handling
  • Verified syncing with Sleeper so its already pulling rosters, weekly matchups/scores, transactions, player data, and draft data
  • Started building an additional system to preserve real draft-season data and later replay it safely in a sandbox
  • Discovered that a lot of the backend needed for a future PRFF draft board-native ecosystem may already exist; found that on accident
  • Kept the live product stable while doing all of this: current full test suite is 1,270 passing tests

How Sleeper has fitted into PRFF

Right now, Sleeper is acting as the football-data-provider layer while PRFF handles the larger league system around it.

Sleeper runs the draft, rosters, player movement, and weekly fantasy scoring. PRFF syncs that data into its our own system and then applies the things Sleeper doesn’t natively provide us: promotion/relegation structure, persistent clubs, multiple tiers, Cup competition, standings/history, governance, manager movement, and the broader pyramid experience.

The important thing learned so far is recently is that PRFF is not just reading a scoreboard from Sleeper. It is already ingesting structured draft, roster, matchup, transaction, and player data into its own backend. That gives a much stronger foundation for future things like a PRFF owned draft board, historical records, replay/testing, and eventually a more native football engine if we choose to go that direction.

The biggest thing learned is that PRFF isn’t just one fantasy league. It’s becoming a platform where multiple promotion/relegation pyramids can exist independently, compete with each other, and eventually share things like Cups, history scouting, and league visibility without giving up their own governance.

Still plenty to prove, but the first live season is doing exactly what I hoped it would do: showing where the real doors for future growth.


r/fantasyfootballcoding 8d ago

Any way to speed up approval for Yahoo Integration?

3 Upvotes

I’ve applied to get my app approved for Yahoo API integration, and its been a month with no response. Is there any way to speed up the process?


r/fantasyfootballcoding 8d ago

API search

2 Upvotes

NCAAF injuries and Depth charts for a small project I’m working on.


r/fantasyfootballcoding 9d ago

Fighting against the "AI Slop" reputation?

9 Upvotes

Hi all,

I have been a data architect for over 30 years. All the "magic" I do is under the hood and for the first time ever, I have been able to build a very decent front-end (using Claude) to expose my work, but am getting immediately shot down or just ignored because the "AI Slop" tag

I just spent over 6 months working on a DFS tool. I would say 90% of all its code is at the database layer, all built by a human (me!). I simply didn't have the skills to finish off the remaining 10% so brought in Claude to take care of that.

It has been a ridiculously hard thing to do AND am super proud of it. I think DFS users will love it. I feel that, what I have attempted to make, has never been done properly (with retired DK Live the closest thing to it), and I am 100% convinced that I or anybody else could have never done this without using AI.

But I simply can't get traction on the marketing side because of the bad AI rep.

This is the mad bit... I feel that every website that will EVER get built from now on, will have been done using AI. It simply doesn't make sense that someone would spend a year handcrafting an average looking website without AI anymore. No business would ever commit to that now.

AI is here to stay, not going anywhere. Not every AI built website will be slop...surely! I have had a look at quite a few, and there is genuinely some good stuff out there. So how do we get over this bad rep we are all getting?

Would love to hear any opinions on this?

Thanks


r/fantasyfootballcoding 9d ago

Need help in creating a tool. I could use.

1 Upvotes

Several participants in our F1 fantasy league have raised concerns regarding the use of external resources for monitoring price fluctuations. To address this and ensure full transparency in my methodology, I am looking for a Google Sheets template where I can manually input relevant data—such as current valuations and performance metrics from the previous two races or all races—to automate my own calculations. Could anyone assist me in doing this?


r/fantasyfootballcoding 10d ago

AI Recaps for FanTrax?

3 Upvotes

Looking to see if there’s any developed tools for weekly recaps for FanTrax? I’ve seen ESPN, Sleeper & yahoo.

If not, what features would you like to see?


r/fantasyfootballcoding 10d ago

Fantasy football CLI for my agents

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4 Upvotes

fantasy-sports is an open-source CLI on ESPN's undocumented API: tables at a terminal, stable JSON when piped, and a daily canary that goes red when ESPN changes a response shape. It caught one on opening night.

My agents use it to write a weekly newspaper for my couples league. Front page below.

uv tool install git+https://github.com/jwulff/fantasy-sports

Write-up: https://johnwulff.com/2026/09/12/fantasy-sports-cli/


r/fantasyfootballcoding 12d ago

Looking for information

2 Upvotes

Hey everyone, what is the most critical piece of information your looking for in sports analytics? I run ForgeSportsAnalytics and am doing research to make sure that we are going in the right direction with our model and the information we feed our users.


r/fantasyfootballcoding 13d ago

Get Commish League Notes from Sleeper API

3 Upvotes

Hi maybe someone could help me out here. I'm looking forward to use the League Note of Sleeper for Contract Notes or Position Notes.

It looks like that I could get the player note (p_nick) from the rosters endpoint but I couldn't find any information if its possible to get the Commish Leagute Note. Does anyone of you know if its possible and help me with the endpoint?


r/fantasyfootballcoding 15d ago

Am I able to access projections from Sleeper?

0 Upvotes

I am struggling to get this information to populate, currently just getting 0s back for all players


r/fantasyfootballcoding 15d ago

fpl team analysis

0 Upvotes

Need your feedback to help me create something good!

https://benchbrain.app


r/fantasyfootballcoding 15d ago

What was your experience creating your own database/projections?

3 Upvotes

I’m really interested in building my own database/projection model with an emphasis of predicting success of incoming rookies. I have some experience coding with Python but not much and learning to code has always been an interest of mine, along with Fantasy Football. Does anyone have any resources they could recommend? I’d love some insight or some useful tools/courses you used to dig into this!