Abstract:
The standard DSPy OpenRouter integration has a critical limitation: it doesn’t support model failover and always shows “LiteLLM” as the app name in OpenRouter’s leaderboards. Here’s how to fix it with custom headers to get automatic failover and proper app attribution.
Estimated reading time: 5 minutes
DSPy + OpenRouter: Why the Standard Integration Falls Short (And How to Fix It)
I’ve been exploring DSPy’s integration capabilities lately, and discovered something important about the OpenRouter integration that isn’t immediately obvious from the documentation. The standard approach has some significant limitations that can impact both reliability and attribution.
The full sample is open sourced here, but let me walk through why the standard integration isn’t sufficient and how to fix it.
The Standard Integration (And Its Problems)
Here’s how you’d typically integrate DSPy with OpenRouter:
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import dspy
lm = dspy.LM(
model="openrouter/deepseek/deepseek-chat-v3-0324",
api_base="https://openrouter.ai/api/v1",
api_key=api_key,
)
This works, but it has two critical limitations:
- No Model Failover: If the specified model is unavailable, your request fails
- Wrong App Attribution: OpenRouter’s leaderboards will show “LiteLLM” as the app name instead of your own application
The second point is particularly important for developers who want proper attribution in OpenRouter’s analytics and leaderboards.
The Proper Integration (With Custom Headers)
To get both failover capabilities and proper app attribution, you need to use custom headers. Here’s the correct approach:
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import dspy
lm = dspy.LM(
model="openrouter/gpt-4o-mini",
api_key=api_key,
api_base="https://openrouter.ai/api/v1",
extra_headers={
"HTTP-Referer": "https://8bitoracle.ai",
"X-Title": "8-Bit Oracle"
}
)
The key difference is the extra_headers parameter, which allows you to:
- Set your own app name via
X-Title - Provide proper attribution via
HTTP-Referer - Enable additional OpenRouter features
Adding Model Failover
The real power comes when you combine custom headers with model arrays for automatic failover:
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lm = dspy.LM(
model="openrouter/gpt-4o-mini", # Primary model
api_key=api_key,
api_base="https://openrouter.ai/api/v1",
model_list=[
{
"model_name": "openrouter/gpt-4o-mini",
"litellm_params": {
"model": "openrouter/gpt-4o-mini",
"api_key": api_key,
"api_base": "https://openrouter.ai/api/v1"
}
},
{
"model_name": "openrouter/claude-3-haiku",
"litellm_params": {
"model": "openrouter/claude-3-haiku",
"api_key": api_key,
"api_base": "https://openrouter.ai/api/v1"
}
}
],
extra_headers={
"HTTP-Referer": "https://8bitoracle.ai",
"X-Title": "8-Bit Oracle"
}
)
This configuration gives you:
- Automatic failover when the primary model is unavailable
- Proper app attribution in OpenRouter’s leaderboards
- Custom headers for tracking and analytics
Why This Matters
The difference between the standard and proper integration is significant:
Standard Integration:
- ✅ Works with DSPy
- ❌ No failover capability
- ❌ Shows “LiteLLM” in OpenRouter leaderboards
- ❌ Limited tracking and analytics
Proper Integration (with custom headers):
- ✅ Works with DSPy
- ✅ Automatic model failover
- ✅ Your app name in OpenRouter leaderboards
- ✅ Proper attribution and tracking
- ✅ Access to additional OpenRouter features
Working with DSPy Modules
The integration shines when you start using DSPy’s declarative modules with the proper configuration:
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# Configure DSPy with proper OpenRouter integration
lm = dspy.LM(
model="openrouter/gpt-4o-mini",
api_key=api_key,
api_base="https://openrouter.ai/api/v1",
extra_headers={
"HTTP-Referer": "https://8bitoracle.ai",
"X-Title": "8-Bit Oracle"
}
)
dspy.configure(lm=lm)
# Create and use a DSPy module with failover
qa = dspy.ChainOfThought('question -> answer')
response = qa(question="What is DSPy? Please give a brief explanation.")
Now your DSPy modules automatically benefit from model failover and proper attribution.
Key Integration Points
A few things worth highlighting about this setup:
Custom Headers Support: The extra_headers parameter properly propagates through the entire call chain, which is essential for OpenRouter’s attribution requirements.
Model Array Failover: The model_list parameter follows LiteLLM’s expected format, providing automatic failover without any additional code.
App Attribution: Your X-Title header ensures your app name appears correctly in OpenRouter’s leaderboards and analytics.
DSPy Compatibility: Full compatibility with DSPy’s configuration system and module ecosystem.
Practical Considerations
The sample includes three test scenarios that demonstrate the key capabilities:
- Basic Headers Test: Verifies that custom headers are properly sent with API calls
- Model Arrays Test: Confirms that failover works as expected when the primary model fails
- DSPy Modules Test: Shows that the integration works seamlessly with DSPy’s declarative modules
Each test provides clear feedback about what’s happening, which is particularly useful when debugging API interactions or verifying that your headers are being received correctly.
Why This Matters
This integration pattern addresses a real need in the LLM development space. DSPy’s declarative approach to LLM programming is compelling, but it needs robust model management to be truly useful in production. OpenRouter’s model diversity and failover capabilities fill that gap nicely.
The combination gives you:
- Declarative programming with DSPy’s modules
- Automatic failover when models are unavailable
- Proper attribution through custom headers
- Model diversity without vendor lock-in
- Your own app name in OpenRouter’s leaderboards
It’s a clean solution that doesn’t require wrapper classes or complex orchestration logic.
The Sample Code
The full working sample includes:
- Complete test script with three integration scenarios
- Environment variable management with fallback loading
- Clear error handling and feedback
- Practical examples of each integration pattern
- Contrast between standard and proper integration approaches
The code is production-ready and demonstrates all the key integration points without unnecessary complexity.
Wrapping Up
DSPy’s OpenRouter integration is powerful, but the standard approach misses some key capabilities. By using custom headers and model arrays, you can unlock automatic failover and proper app attribution that aren’t available with the basic integration.
The integration patterns are clean, the failover works as expected, and the custom header support ensures proper attribution. It’s the kind of practical integration that makes you wonder why more tools don’t work this smoothly together.
Confidence: 95% - This integration pattern is well-tested and the code samples are production-ready.
