LangSmith
AI Agent & LLM Observability Platform
VS
M
Mellea
Structured, validated LLM output for robust, reliable AI system integration.
Detailed comparison
Criteria
LangSmith
Mellea
Pricing
Freemium
Free
Plans & pricing
Developer: Free, Team: $39/mo, Enterprise: Custom
—
Free trial
No
—
Audience
b2b
B2B
Platforms
Web
—
API
Yes
—
Open Source
Proprietary
—
Integrations
Pagerduty
—
Categories
Dev & Tech, information technology & services, Apps
Dev & Tech, AI & ML
Popularity
Very High
Low
Description
LangSmith is a complete AI agent and LLM observability platform. It offers tracing and real-time monitoring to help developers debug agents, find fail...
Mellea is an open-source Python library designed for structured and validated Large Language Model (LLM) output. It enables developers and AI builders...
Pricing
LangSmith
Freemium
Mellea
Free
Plans & pricing
LangSmith
Developer: Free, Team: $39/mo, Enterprise: Custom
Mellea
—
Free trial
LangSmith
No
Mellea
—
Audience
LangSmith
b2b
Mellea
B2B
Platforms
LangSmith
Web
Mellea
—
API
LangSmith
Yes
Mellea
—
Open Source
LangSmith
Proprietary
Mellea
—
Integrations
LangSmith
Pagerduty
Mellea
—
Categories
LangSmith
Dev & Tech, information technology & services, Apps
Mellea
Dev & Tech, AI & ML
Popularity
LangSmith
Very High
Mellea
Low
Description
LangSmith
LangSmith is a complete AI agent and LLM observability platform. It offers tracing and real-time monitoring to help developers debug agents, find fail...
Mellea
Mellea is an open-source Python library designed for structured and validated Large Language Model (LLM) output. It enables developers and AI builders...
Features
LangSmith
Cost tracking
Online LLM-as-judge and code evals
Tool and agent trajectory monitoring
Webhook and Pagerduty alerts
Message threading for multi-turn chat interactions
Templates for error analysis
Mellea
Generative Functions for structured LLM output using typed Python functions.
Requirements-driven approach with automatic validation and retry strategies.
Broad compatibility with many inference services and model families (e.g., OpenAI, Ollama).
Constrained Decoding to enforce valid output at the token level for supported models.
Key differentiators
LangSmith
- Complete AI agent & LLM observability
- Real-time tracing, debugging & evals
- Cost, latency & trajectory monitoring
Mellea
Other comparisons
FAQ: LangSmith vs Mellea
LangSmith: AI Agent & LLM Observability Platform. Mellea: Structured, validated LLM output for robust, reliable AI system integration.. Both tools take different approaches to address similar needs.
Both offer a free or freemium plan. LangSmith is freemium and Mellea is free.
The best choice between LangSmith and Mellea depends on your specific needs. Compare their features, pricing, and target audience on this page to find the tool that best fits your use case.
LangSmith is primarily designed for individuals, while Mellea is built for businesses and professionals.
LangSmith offers: Cost tracking, Online LLM-as-judge and code evals, Tool and agent trajectory monitoring, Webhook and Pagerduty alerts. Mellea offers: Generative Functions for structured LLM output using typed Python functions., Requirements-driven approach with automatic validation and retry strategies., Broad compatibility with many inference services and model families (e.g., OpenAI, Ollama)., Constrained Decoding to enforce valid output at the token level for supported models..
Based on our data, LangSmith currently enjoys greater popularity. However, popularity isn't the only factor — compare features to find the right tool for your needs.