HumanLoop Shutdown: Guide to Migrating Your Prompts and Evals to PromptLayer

HumanLoop shut down on September 8, 2025. If your team relied on HumanLoop for prompt management, evaluations, and observability, you may still be looking for a stable replacement. PromptLayer offers everything HumanLoop did—and more.

What is PromptLayer?

PromptLayer is a comprehensive prompt engineering platform that serves as the “Git for prompts,” helping teams manage, version, and improve prompts with confidence. Founded in 2023, it provides:

• Prompt Registry: Version control and management for all your prompts
• Evaluations: Automated testing to ensure prompt quality
• Observability: Complete logging and analytics for LLM interactions
• Collaboration: No-code interface for non-technical team members
• A/B Testing: Built-in experimentation capabilities

PromptLayer was built from day one to empower both engineers AND domain experts (doctors, lawyers, marketers) to collaborate on AI development.

1:1 Feature Mapping: HumanLoop → PromptLayer

Here's how HumanLoop features map directly to PromptLayer:

All that, plus some more features.

PromptLayer isn't just a replacement—it's an upgrade:

1. Better Collaboration Features

• Threaded comments on prompt changes
• WYSIWYG no-code editor designed for non-engineers
• Domain experts can directly experiment without touching code

2. More Powerful Evaluations

• Conversation Simulator: Test multi-turn agent interactions
• Spreadsheet-like Pipeline: Chain multiple evaluation types
• 6-minute code execution: More time for complex evaluations
• Built-in eval templates for common use cases

3. Superior A/B Testing

• Native A/B testing with traffic splitting
• Real-time performance comparison
• No code changes needed—just toggle in the UI

4. Native Agents + Framework Flexibility

• Built-in Agents feature for complex workflows
• Also works with ANY LLM framework (LangChain, OpenAI Functions, etc.)
• Not locked into a proprietary agent runtime
• Use your preferred tools while getting PromptLayer's benefits

5. Active Development

• Well-funded with recent seed round (2025)
• Rapid feature releases based on user feedback
• Direct access to founders for support

Quick Migration Guide

Step 1: Export Your HumanLoop Data (Before Sept 8!)

• Prompts and versions
• Evaluation datasets and results
• Logs and feedback
• Use HumanLoop's API endpoints for export

Step 2: Set Up PromptLayer

# Install PromptLayer
pip install promptlayer

# Initialize with your API key
import promptlayer
promptlayer.api_key = "YOUR_API_KEY"

Step 3: Import Your Prompts

• Create prompts in PromptLayer's Registry
• Copy prompt templates and versions
• Add metadata and comments for context

Step 4: Recreate Evaluations

• Upload test datasets (CSV/JSON supported)
• Rebuild evaluators using PromptLayer's evaluation types
• Run baseline evaluations to verify parity

Step 5: Update Your Code

# Before (HumanLoop)
from humanloop import Humanloop
hl = Humanloop(api_key="...")

# After (PromptLayer)
from promptlayer import PromptLayer
pl = PromptLayer(api_key="...")

Step 6: Start Logging

• Replace API calls with PromptLayer's wrapper
• Verify logs appear in the dashboard
• Set up any needed alerts or monitoring

Take Action Today

With HumanLoop shutting down September 8, 2025, you have limited time to migrate. PromptLayer offers:

• ✅ All of HumanLoop's core features
• ✅ Additional capabilities for better collaboration and testing
• ✅ Active development and support
• ✅ Competitive pricing
• ✅ Easy migration path

Ready to migrate? Sign up at PromptLayer.com and reach out to our team—we're actively helping HumanLoop users transition smoothly.