Pydantic Logfire
AI observability platform for production LLM and agent systems, built on OpenTelemetry with end-to-end application tracing
4.3K
GitHub Stars
10M
Free Records/Mo
3
SDK Languages
Overview
Pydantic Logfire is an AI observability platform built by the creators of Pydantic, designed for production LLM and agent systems. Unlike tools that focus solely on LLM calls, Logfire provides end-to-end visibility across entire applications—capturing database queries, API requests, business logic, and AI components in unified traces. Built natively on OpenTelemetry, it features real-time LLM cost tracking, a SQL query interface for data analysis, live span viewing, and an integrated evaluation framework (Pydantic Evals). It supports Python, JavaScript/TypeScript, and Rust SDKs.
The Verdict
Who Should Use Pydantic Logfire?
Best For
- Teams already using Pydantic in their stack
- Full-stack observability (not just LLM calls)
- OpenTelemetry-native architectures
- Multi-language applications (Python, TS, Rust)
- Real-time cost tracking and optimization
Not Ideal For
- Self-hosted requirements (cloud-only currently)
- Teams needing LangChain-native integration
- Simple single-model apps (may be overkill)
- Non-Python shops without OTel expertise
What's Great
- OpenTelemetry-native - works with existing OTel setup
- Full-stack tracing beyond just LLM calls
- Built by Pydantic team - first-class Pydantic AI support
- SQL query interface for custom analytics
- Real-time cost tracking per trace
- Live span viewing before completion
- Multi-language SDKs (Python, JS/TS, Rust)
- Generous free tier (10M records/month)
Watch Out For
- No self-hosted option (Enterprise has data residency)
- Newer platform, smaller community than Langfuse
- Best experience requires Pydantic ecosystem buy-in
- Less mature than established APM tools
Pricing
Free
$0
10M records/mo, 1 seat, 30-day retention
Team
$49/mo
5 seats, 5 projects, $2/M additional records
Growth
$249/mo
Unlimited seats, priority support, HIPAA BAA
Enterprise
Custom
Self-hosting options, data residency
View all features & details
Core Features
- Distributed tracing with nested spans
- Real-time LLM cost analytics
- SQL query interface
- Live span viewing
- Pydantic Evals integration
- MCP server for code editors
- Metrics & logs unified view
AI Integrations
- Pydantic AI
- OpenAI SDK
- Anthropic SDK
- LangChain
- LlamaIndex
- Instructor
- Mirascope
Framework Support
- FastAPI
- Django
- Flask
- Next.js
- Express
- Node.js
- PostgreSQL / MongoDB / Redis
Platform
- OpenTelemetry-native
- Python SDK (MIT licensed)
- JavaScript/TypeScript SDK
- Rust SDK
- Cloud-hosted (US/EU)
- HIPAA compliant (Growth+)
How It Compares
| Feature | Logfire | Langfuse | LangSmith | Datadog LLM |
|---|---|---|---|---|
| Open Source | SDK only | Fully OSS | No | No |
| Self-Hosted | Enterprise | Yes | No | No |
| Free Tier | 10M records | 50K obs | 5K traces | Trial |
| OTel Native | Yes | No | No | Yes |
| Full-Stack Tracing | Yes | LLM-focused | LLM-focused | Yes |
| SQL Interface | Yes | No | No | Yes |
| Pydantic Support | Native | Via SDK | Via SDK | Via SDK |
| Best For | Pydantic/OTel teams | Self-hosted | LangChain | Enterprise |
User Reviews
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