LangSmith vs Phoenix: Pricing and Ratings Compared (2026)
Entry prices and free plans as read on each vendor's pricing page, and user ratings as published on review sites, for LangSmith and Phoenix side by side. This page compares data; it is not a hands-on review.
On the data: On the data below, LangSmith leads on lower entry price. We do not name an overall winner for this pair.
Short on time? Here's the quick answer
Based on published vendor pricing and features and on public review data, here's who should pick what:
LangSmith
Debug, monitor, and optimize your LLM applications and AI agents with comprehensive observability.
Best for you if:
- • You want provides deep visibility into non-deterministic LLM behavior
Phoenix
Evaluate, experiment, and optimize AI products in real time with open-source LLM tracing.
Best for you if:
- • You want open-source and self-hostable, offering flexibility and no vendor lock-in
| At a Glance | LangSmith | Phoenix |
|---|---|---|
Starts at | Free plan, paid from $39/seat/mo, billed monthly Plus plan | Free plan, paid from $50/mo, billed monthly AX Pro plan |
Category | AI Agents Developer Tools | Developer Tools Analytics |
Rating | n/a | n/a |
Free plan | Yes | Yes |
Watch out for | Traces over the included 5k/10k are pay-as-you-go. Seats are only the floor. | Overage fees for exceeding trace spans/ingestion |
Choose LangSmith or Phoenix?
Choose LangSmith if
- You want provides deep visibility into non-deterministic LLM behavior
- You want helps improve application performance and response quality
- Budget matters ($39/seat/mo, billed monthly vs $50/mo, billed monthly)
- You work in AI agents, not developer tools
Choose Phoenix if
- You want open-source and self-hostable, offering flexibility and no vendor lock-in
- You want provides deep observability into LLM behavior and decision-making
- You work in developer tools, not AI agents
In-Depth Analysis
LangSmith
Debug, monitor, and optimize your LLM applications and AI agents with comprehensive observability.
LangSmith Developer is $0 for one seat and 5,000 base traces/month.
Watch out
Traces over the included 5k/10k are pay-as-you-go. Seats are only the floor.
Strengths
- Pro: Provides deep visibility into non-deterministic LLM behavior
- Pro: Helps improve application performance and response quality
- Pro: Offers comprehensive monitoring and alerting capabilities
- Pro: Identifies systemic issues and user needs automatically
- Pro: Flexible integration with various frameworks and OTel
Weaknesses
- Con: Specific pricing details require visiting a separate page
- Con: Self-hosting is only available on the enterprise plan
- Con: Requires some setup (e.g., environment variables) to get started
Key features
Phoenix
Evaluate, experiment, and optimize AI products in real time with open-source LLM tracing.
Phoenix offers a very generous free tier with its open-source solution and a substantial free tier for AX, making it highly accessible.
Watch out
Overage fees for exceeding trace spans/ingestion
Strengths
- Pro: Open-source and self-hostable, offering flexibility and no vendor lock-in.
- Pro: Provides deep observability into LLM behavior and decision-making.
- Pro: Facilitates rapid experimentation and iteration with interactive playgrounds.
- Pro: Supports both automated and human feedback for comprehensive evaluations.
- Pro: Strong community support and integrations with popular LLM frameworks.
Weaknesses
- Con: Advanced features like dedicated support and custom data limits are only available in higher-tier paid plans.
- Con: The free SaaS tier has limited trace spans and ingestion volume.
- Con: Requires some technical expertise for self-hosting and full utilization.
Key features
Plans and prices: LangSmith vs Phoenix
| Tool | Plans and prices | Source |
|---|---|---|
| LangSmith |
| langchain.com/pricing read Oct 12, 2026 |
| Phoenix |
| phoenix.arize.com/pricing read Oct 13, 2026 |
Prices as read on each vendor's own pricing page on the date shown. Plans are listed per tool and are not matched against the other tool's plans: a plan name or price in one column says nothing about the same row in the other. Details on LangSmith pricing and Phoenix pricing.
Key Takeaways
LangSmith
- Lower entry price: $39/seat/mo, billed monthly vs $50/mo, billed monthly
Phoenix
- Choose if you want evaluate, experiment, and optimize AI products in real time with open-source LLM tracing
What the data shows
On the data below, LangSmith leads on lower entry price. We do not name an overall winner for this pair.
- LangSmith has the lower entry price: $39/seat/mo, billed monthly (Plus) against $50/mo, billed monthly (AX Pro) for Phoenix.
- Both have a free plan.
Criteria: user rating (only above 20 reviews on both sides, gap of 0.2 or more), entry price (only on the same billing basis), free plan. How we rate
Frequently Asked Questions
How do LangSmith and Phoenix compare in 2026?
On the data below, LangSmith leads on lower entry price. We do not name an overall winner for this pair. LangSmith has the lower entry price: $39/seat/mo, billed monthly (Plus) against $50/mo, billed monthly (AX Pro) for Phoenix. Both have a free plan.
What are LangSmith and Phoenix used for?
LangSmith: Debug, monitor, and optimize your LLM applications and AI agents with comprehensive observability. Phoenix: Evaluate, experiment, and optimize AI products in real time with open-source LLM tracing.
What does LangSmith cost vs Phoenix?
LangSmith's cheapest paid plan is Plus at $39/seat/mo, billed monthly; it also has a free plan. Phoenix's cheapest paid plan is AX Pro at $50/mo, billed monthly; it also has a free plan. Prices read on the vendors' pricing pages, latest check Oct 13, 2026.
What's the main difference between LangSmith and Phoenix?
LangSmith's main strength: provides deep visibility into non-deterministic LLM behavior. Phoenix's main strength: open-source and self-hostable, offering flexibility and no vendor lock-in.