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A/B Testing API Cost (Annual) Calculator

Estimate the yearly cost of an A/B testing API from experiment traffic, API calls, included usage, overage pricing and platform fees.

Your Details

Overview

This A/B testing API cost calculator estimates your annual testing-platform spend using monthly evaluated traffic, API calls per visitor, the share of traffic in experiments, concurrent tests, included usage, and pricing. It can help you compare expected usage with a vendor plan allowance before setting a budget.

How it works

The calculator estimates monthly API calls by multiplying monthly evaluated visitors by calls per visitor, the share of traffic in experiments, and the average number of active experiments. It subtracts the plan's included monthly calls and applies the entered overage price to any excess. The fixed monthly platform fee and overage charge are then multiplied by 12 to estimate the annual cost.

How to use this calculator

  1. 1Enter the average number of visitors or sessions evaluated each month.
  2. 2Add the average number of API or decision calls made per evaluated visitor.
  3. 3Set the percentage of traffic that participates in experiments.
  4. 4Enter the average number of concurrent experiments that create separate evaluations.
  5. 5Add your monthly included call allowance, overage rate, and fixed platform fee.
  6. 6Review the estimated monthly and annual costs.

Example Calculation

Monthly visitors evaluated

500000

API calls per evaluated visitor

2

Traffic included in experiments

60%

Average active experiments

3

Included API calls per month

1

Overage cost per million calls

$25

Monthly platform fee

$99

Estimated annual API cost

$1,428

This setup produces an estimated 1.8 million API calls per month. With one million calls included, the estimated monthly cost is $119 and the annual cost is $1,428.

Frequently asked questions

What counts as an A/B testing API call?

It depends on the provider, but it commonly includes a feature-flag evaluation, variation assignment, decision request, or server-side SDK call. Check the provider's billing documentation for its exact definition.

Why does the calculator multiply by active experiments?

The multiplier is useful when one eligible visitor generates a separate API evaluation for each concurrent experiment. If your platform combines decisions into one call, enter 1 or adjust calls per visitor instead.

Should I use visitors, users, or sessions?

Use whichever measure most closely matches how your provider records billable API usage. For example, if calls occur once per session, use sessions rather than unique users.

Does the annual estimate include unused monthly API calls?

No. The calculator treats the allowance as monthly and assumes unused calls do not carry forward. Update the estimate if your plan includes rollover usage.

How can I reduce A/B testing API costs?

You can review whether every decision needs a real-time call, reduce duplicate evaluations, use caching where appropriate, limit test eligibility, or select a plan with a better allowance for your usage pattern.

Are taxes and enterprise contract discounts included?

No. The estimate uses only the platform fee and overage rate you enter. Taxes, annual commitments, discounts, implementation costs, and support fees may change the actual total.

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Assumptions and warnings

Assumptions

  • Monthly traffic, experiment participation, active experiments, and calls per visitor remain consistent throughout the year.
  • Each active experiment is assumed to create a separate API evaluation for an eligible visitor.
  • Included API calls are treated as a monthly allowance that does not roll over to later months.
  • The estimate includes the entered fixed platform fee and per-million overage price only.
  • Actual vendor billing may use different definitions for API calls, users, events, rounding, minimum commitments, or billing periods.

Warnings

  • This calculator provides a cost estimate only and is not financial advice.
  • Check your provider's current pricing, usage definitions, contract terms, taxes, and billing rules before making purchasing decisions.