Lago Open-source SDK: Bill on top of your LLM token cost with no middleware
The Lago Open-source SDK allows users to instrument LLM clients for billing without changing application code. It extracts usage data from responses and sends it to Lago's API in batches, ensuring minimal overhead. The SDK supports multiple providers and offers a flexible subscription management system.
- ▪Lago's SDK wraps existing LLM clients, enabling usage tracking without altering application code.
- ▪It buffers usage events in memory and sends them to Lago's API, surviving outages with exponential backoff.
- ▪The SDK supports various providers, including AWS Bedrock and Mistral, and allows for multi-tenant subscription management.
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lago-agent-sdk Instrument LLM clients and emit usage events to Lago for billing. ┌──────────────┐ your code ──────► │ wrapped client│ ──► provider (Bedrock / Mistral / …) └──────┬───────┘ │ (extract usage) ▼ ┌──────────────┐ │ Lago events │ ──► api.getlago.com └──────────────┘ What it does Wraps your existing LLM client in place — no API surface change for your application code. Extracts usage from each response into a normalized shape (CanonicalUsage). Buffers events in memory, flushes them in batches to Lago's /events/batch endpoint. Survives provider/Lago outages with exponential backoff and a bounded buffer. p99 wrap-overhead under 5 ms — your call is never blocked on Lago. Install pip install lago-agent-sdk For Bedrock support: pip install 'lago-agent-sdk[bedrock]' (adds boto3).
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Excerpt limited to ~120 words for fair-use compliance. The full article is at GitHub.