StackLens

FlowOps

FlowOps is prompt version control for production AI systems. Manage prompts as engineering artifacts — with versioning, environments, approval gates, and A/B testing — not as strings scattered across code and Notion docs.

What it does

  • Versioning — every change to a prompt creates a new version. Roll back in one click.
  • Environments — separate dev, staging, and production environments for each prompt. Promote safely.
  • A/B testing — run two prompt variants simultaneously and measure which performs better.
  • Runtime fetch — fetch the active prompt at runtime via the SDK. Change prompts without redeploying.

Concepts

Project — a logical grouping of prompts (e.g. customer-support, document-pipeline).

Prompt — a named template with a full version history. Each version is immutable once created.

Environment — each prompt has an active version per environment (dev, staging, production). Promoting a version to production is a separate action, not an automatic deploy.

A/B test (Experiment) — splits traffic between two prompt versions by user ID. Results appear in the dashboard.

Fetching prompts at runtime

import stacklens
 
stacklens.configure(api_key="sl-xxxx")
 
# Fetch the active production prompt
system_prompt = stacklens.prompts.get("support-system-prompt", env="production")
 
# Use it in your LLM call
response = openai_client.chat.completions.create(
    model="gpt-4o",
    messages=[
        {"role": "system", "content": system_prompt},
        {"role": "user", "content": user_message},
    ],
)

The SDK fetches the version currently active in the requested environment. If you promote a new version in the dashboard, the next SDK call will receive it automatically — no code change or deploy needed.

Managing prompts

Use the StackLens dashboard to:

  1. Create a project
  2. Create a prompt and write your first version
  3. Promote the version to production
  4. Fetch it from your application via the SDK

A/B testing

# SDK support for A/B testing coming soon

A/B tests are currently configured and monitored via the dashboard.

Dashboard

The FlowOps dashboard shows:

  • Prompt list — all prompts in your organization, by project
  • Version history — full diff view between any two versions
  • Environment status — which version is active in each environment
  • Usage — how many times each prompt was fetched, by environment and day