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

Jonathan Pedoeem July 17, 2025 3 min read

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

Evaluating Conversational AI with PromptLayer - YouTube

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Evaluating Conversational AI with PromptLayer PromptLayer

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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.