THE COMPARISON / A CLOSER LOOK

Opik by Comet vs LangSmith

Compare the listed plans, useful capabilities, and practical tradeoffs.

Prices and features reflect editorial records. Check vendor terms before you buy; documentary checks do not imply hands-on testing.

Opik by Comet

🔴Developer

LLM Observability & Evals

Open-source LLM evaluation and observability framework: trace, evaluate, monitor, and improve LLM applications.

SOURCE-CHECK COVERAGE

No scoped source-check record shown. Check current pricing and vendor terms before buying.

Starting Price

Free

LangSmith

🔴Developer

LLM Observability

LangSmith helps developers trace, evaluate, test, and monitor applications built with language models and agent workflows.

SOURCE-CHECK COVERAGE

No scoped source-check record shown. Check current pricing and vendor terms before buying.

Starting Price

Free

Feature Comparison

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FeatureOpik by CometLangSmith
CategoryLLM Observability & EvalsLLM Observability
Pricing Plans4 listed plans1 listed plan
Starting PriceFreeFree
Key Features
  • • Trace & Span Logging: Capture and inspect the steps involved in an LLM application request so teams can understand how prompts, model calls, and application logic contribute to outputs.
  • • LLM Application Improvement: Use trace, evaluation, monitoring, and prompt-related workflows together to support iterative improvement of LLM-backed features.
  • • Open-Source Reviewability: The supplied metadata identifies Opik as open source with an Apache-2 tag, which can help teams inspect, extend, or evaluate the tool before committing to a hosted workflow.
  • • Tracing for any LLM stack via Python/TypeScript SDKs or OpenTelemetry
  • • LLM-as-judge, code-based and pairwise evaluations
  • • Versioned prompts with production A/B traffic splits

Opik by Comet - Pros & Cons

Pros

  • ✓True Apache 2.0 open source with a self-hostable backend — no source-available rug pull risk
  • ✓SDKs for Python, TypeScript, and Ruby (Ruby support is uncommon among competitors)
  • ✓Wide framework coverage: LangChain, LlamaIndex, LiteLLM, CrewAI, AutoGen, DSPy
  • ✓Free hosted cloud is genuinely usable for individuals and small teams
  • ✓Backed by Comet's mature ML observability lineage, not a brand-new startup

Cons

  • ✗Self-hosting Opik requires real DevOps work — not a Docker-and-forget situation at scale
  • ✗Some evaluators are still maturing compared to specialist eval tools like Braintrust
  • ✗Team-tier pricing is gated behind sales contact
  • ✗Ecosystem is smaller than LangSmith for LangChain-specific workflows

LangSmith - Pros & Cons

Pros

  • ✓Makes multi-step LLM failures easier to localize than application logs alone
  • ✓Connects production traces, datasets, experiments, and evaluations in one workflow
  • ✓Particularly natural for teams already building with LangChain or LangGraph
  • ✓Supports repeatable release checks instead of subjective prompt spot-testing

Cons

  • ✗Useful evaluations require ongoing dataset curation and carefully designed scoring criteria
  • ✗LLM-as-judge results can be noisy and should not replace expert review for high-risk outputs
  • ✗Captured traces may contain sensitive prompts, documents, and tool results
  • ✗Current pricing and usage limits could not be verified from vendor pages in this environment

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🔒 Security & Compliance Comparison

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Security FeatureOpik by CometLangSmith
SOC2—✅ Yes
GDPR—✅ Yes
HIPAA——
SSO—✅ Yes
Self-Hosted—🔀 Hybrid
On-Prem—✅ Yes
RBAC—✅ Yes
Audit Log—✅ Yes
Open Source—❌ No
API Key Auth—✅ Yes
Encryption at Rest—✅ Yes
Encryption in Transit—✅ Yes
Data Residency—US, EU
Data Retention—configurable
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