What does it cost to build this for real?
This is not the cost of a single-sport notebook or a weekend prototype. Set your engineer rate and sports coverage to estimate the year-one cost of building and maintaining a sports prediction API under the planning assumptions below.
Production preset: an illustrative five-sport planning scenario; adjust the inputs for your actual project.
Default assumption: $150/hour. Enter your own loaded rate; this is not a salary survey or contractor quote.
A lower hourly rate changes the cost scenario. Evaluate experience, scope, calibration and maintenance separately; the rate alone does not establish quality.
The public API documents eight sports: NBA, WNBA, NCAAMB, NCAAWB, CFB, NFL, NHL and MLB. Research and bot coverage can differ. See API documentation for supported endpoints. This estimator assumes 40 hours of separate Elo and calibration work per sport.
Build from scratch
ItemizedBuy from ZenHodl API
Full pricing →Pick the tier that fits your usage — savings recompute below.
The buy-side estimate is the selected subscription price only. Your integration, execution, data validation and risk controls are additional work. API documentation states endpoint coverage and access.
Estimated cost difference
5-year cumulative cost
DIY year one includes the assumed build hours, maintenance, hosting and data. Years 2–5 repeat those assumed ongoing costs. The API line repeats the selected subscription price; future price changes, customer integration, hiring and re-platforming are outside this scenario.
Compare the alternatives you are considering
For a repository, contractor or API vendor, check the same evidence. Capabilities and costs vary by provider; this page does not claim category-wide timelines, accuracy or prices.
| Question | Evidence to inspect |
|---|---|
| Does it cover your games and venues? | Endpoint list, dated sample and per-source quote age. ZenHodl docs |
| How was probability quality measured? | Test dates, model version, exclusions, calibration bins and a matched baseline. Selected ZenHodl benchmarks |
| Can you inspect recorded outcomes? | Ledger inclusion rules and execution-identifier coverage. Filtered ZenHodl results |
| What must your team maintain? | Data adapters, monitoring, retraining, integration, execution and risk controls. |
| What is the full project cost? | Subscription or contractor quote, your engineering hours, data licenses and ongoing maintenance. |
Why building is harder than it looks
The defaults are an illustrative planning scenario inspired by our development work. The public page does not provide a timesheet study; replace the inputs with your own scope and estimates.
- Calibration. Fit corrections separately from the test set and measure probability error on unseen games. Calibration can improve or worsen under a new regime.
- Look-ahead bias. Freeze team priors and select inputs available at the prediction time; a chronological split alone cannot prove the absence of leakage.
- Sport-specific modeling. The calculator allocates 40 assumed tuning hours per sport; your feature and labeling needs can differ.
- Monitoring. Check missing data, quote age and evaluation drift. A model refresh or poll is not proof of fresh upstream prices.
- Maintenance. The default is 10 hours per month. Change it to match your data adapters, retraining schedule and operational responsibilities.
Our blog covers the real build process in depth, including where we've broken models and how we've fixed them. If you want to build yourself, those posts are a free starting point — but the working system is the API.
When building actually is the right call
We don't think every team should buy. Here are the legitimate cases for building — with how ZenHodl still helps in each one.
Common questions
Is the calculator biased toward "buy"?
The defaults reflect an illustrative development scenario, not a survey of teams or a guaranteed outcome. Both sides omit some project costs: the subscription total excludes customer integration and execution, while the build estimate excludes hiring and re-platforming. Change the inputs and compare against a specific scope or quote.
Why not just hire a contractor for $5k–$10k?
A contractor may be appropriate. Ask for a written scope, dated holdout evaluation, source licenses, maintenance terms and integration responsibilities. Compare that actual quote with the subscription plus your own engineering work.
What about open-source projects on GitHub?
A repository can be a useful starting point. Check its license, supported data sources, maintenance history, chronological evaluation and deployment requirements. Estimate the work needed for that specific repository; this calculator does not measure the quality or cost of all open-source projects.
Can I cancel after the trial?
Yes — one click in your dashboard. We email a reminder before the trial converts so nobody gets surprised. There is no contract and no long-term commitment.
How do I know your predictions are actually calibrated?
We publish ECE per sport (4.39% on 5,345 NCAAMB games), a dated benchmark index, filtered public-ledger trades on /results, and selected paired pregame benchmarks with manifest and receipt evidence where published. Inspect each cohort, date, model version and exclusion rule; these studies do not guarantee current calibration or trading profit.
Methodology
Build-cost defaults are illustrative assumptions inspired by our development work; no public timesheet study is supplied. ELO tuning: ~40 hrs/sport. Base infrastructure (XGBoost + isotonic + backtest harness + feature pipeline + monitoring + API): ~280 hrs, amortized across sports. First-year maintenance uses your entered hours and rate. The default scenario assumes $500/mo for data and $200/mo for hosting; these are editable budgets, not provider quotes. ZenHodl's totals reflect subscription cost only; customer-side integration and custom execution remain separate.
The five-year chart holds rates and recurring costs constant. Hiring, re-platforming, future subscription changes and customer-side integration are excluded; actual costs can be higher or lower on either side.
Want to inspect the underlying claims? See our research summary, methodology, live results, transparency index, and plan details.