LangSmith vs PromptLayer
Two of the most-asked-about agents in the developer-tools space. Here's how they actually stack up.
LangSmith
LLM observability, testing, and evaluation platform from the LangChain team
Free tier
Read full review →PromptLayer
Prompt versioning, management, and monitoring for teams shipping LLM applications
Free tier
Read full review →Side-by-side comparison
| LangSmith | PromptLayer | |
|---|---|---|
| Tagline | LLM observability, testing, and evaluation platform from the LangChain team | Prompt versioning, management, and monitoring for teams shipping LLM applications |
| Pricing | Free tier | Free tier |
| Categories | developer-tools, api, productivity | developer-tools, productivity |
| Made by | LangChain | PromptLayer |
| Launched | 2023-09 | 2022-12 |
| Platforms | Web, API | Web, API |
| Status | active | active |
LangSmith highlights
- + Full trace logging for LLM chains with nested step visibility
- + Dataset management: build eval datasets from production traces
- + Automated evaluation with LLM-as-judge scoring
- + Human annotation queues for labeling and quality review
- + Prompt hub for storing and versioning prompts
PromptLayer highlights
- + Prompt versioning with named releases and rollback capability
- + Request log viewer: see every LLM call with full prompt, response, and metadata
- + Search and filter request history by metadata, model, or custom tags
- + Analytics dashboard: track token usage, latency, and cost over time
- + Visual prompt template editor with variable injection
Frequently Asked Questions
Which is better, LangSmith or PromptLayer?
Neither is universally better. LangSmith (Free tier) leans into developer-tools, while PromptLayer (Free tier) is closer to developer-tools. Pick based on which workflow you actually do every day.
What is the price difference between LangSmith and PromptLayer?
LangSmith is free tier. PromptLayer is free tier. See the pricing row in the comparison table.
Can I use LangSmith and PromptLayer together?
In most cases, yes. They serve overlapping but distinct needs, so running them side by side is common until you decide which fits your workflow.