Solutions

Prompt Optimization

Stop guessing which prompt is best. Winnow lets you A/B test variants in production, auto-generate candidates with OPRO, and manage every prompt version through a full Draft → Candidate → Live lifecycle.

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prompt_experiment.pypython

import winnow

# Create a prompt experiment with two variants
experiment = winnow.create_prompt_experiment(
    name="onboarding-welcome-message",
    base_prompt=winnow.prompt("welcome-msg", version="v2.3"),
    variants=[
        {
            "name": "concise",
            "prompt": "You are a friendly assistant. Greet the user "
                      "in one sentence and ask how you can help.",
        },
        {
            "name": "opro-generated",
            "prompt": winnow.opro.generate(
                task="welcome the user warmly and ask their goal",
                optimize_for=["engagement", "clarity"],
                model="gpt-4o",
            ),
        },
    ],
    traffic_split=[50, 50],
    primary_metric="user_engagement_rate",
)

# Promote the winner to Live
experiment.on_winner(
    action="promote",          # Draft -> Candidate -> Live
    confidence_threshold=0.95,
)

The Complete Prompt Engineering Toolkit

From first draft to production rollout, Winnow gives you the tools to write, test, and ship better prompts.

A/B Test Prompt Variants

Split traffic between prompt variants and measure quality, latency, and cost with statistically rigorous sequential testing. Declare winners with confidence.

OPRO Auto-Generation

Let Winnow generate prompt candidates using Optimization by PROmpting (OPRO). Define your task and target metrics, and the optimizer proposes high-performing variants automatically.

Prompt Lifecycle Management

Every prompt version moves through Draft, Candidate, and Live stages with full audit history. Roll back to any previous version in one click if a regression is detected.

Version History & Diffing

See exactly what changed between prompt versions with semantic diffs. Track who made each change, when it was promoted, and how it performed relative to the previous version.

From vibes to versioned, measured prompts

Most teams edit prompts in code and hope for the best. Winnow gives you a structured lifecycle where every change is measured against your baseline before it reaches production users.

Draft: iterate freely in the playground with instant eval feedback

Candidate: run A/B tests against the current Live version

Live: promote winners automatically or with manual approval

OPRO generates dozens of candidates in minutes, not days

Rollback to any version instantly if metrics degrade

Optimize every prompt with data, not intuition

Run your first prompt experiment in under five minutes. Free for up to 10 active experiments.

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