Langfuse vs Keywords AI / Respan

Detailed side-by-side comparison to help you choose the right tool

Langfuse

🔴Developer

AI observability

An open-source observability and evaluation platform for language-model applications.

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Starting Price

Free
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Keywords AI / Respan

🔴Developer

AI observability

LLM monitoring and gateway platform for AI applications

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Starting Price

$0
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Feature Comparison

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FeatureLangfuseKeywords AI / Respan
CategoryAI observabilityAI observability
Pricing Plans5 listed plans3 listed plans
Starting PriceFree$0
Key Features
  • • Hierarchical Tracing & Agent Debugging
  • • Production Prompt Management & Versioning
  • • LLM-as-Judge Evaluation Framework
  • • End-to-end agent tracing with prompt, tool call and response context
  • • Evaluation workflows with human review, code checks and LLM judges
  • • Gateway, observability, evaluations and prompt optimization features

Langfuse - Pros & Cons

Pros

  • ✓Open source with free self-hosting — full feature parity without usage limits
  • ✓Free Hobby tier on cloud with no credit card — lowest barrier to entry in the category
  • ✓Trace graphs for multi-agent systems are genuinely useful for debugging complex failures
  • ✓Prompt management + evals turns prompt engineering into a systematic, measurable process
  • ✓40,000+ builders using it — extensive community resources and integrations
  • ✓Integrates natively with LangChain, LlamaIndex, OpenAI SDK, and Anthropic

Cons

  • ✗Pro plan units pricing ($8/100k) can add up for high-volume production applications
  • ✗Enterprise SSO requires the $300/month Teams add-on on top of Pro — costly for mid-size teams
  • ✗Self-hosting requires Docker/Kubernetes operational knowledge
  • ✗UI can feel overwhelming for teams who just want simple cost/latency dashboards
  • ✗Real-time alerting features are less developed than commercial-first alternatives like Arize
  • ✗Enterprise tier at $2,499/month is priced for large organizations — no mid-market option

Keywords AI / Respan - Pros & Cons

Pros

  • ✓Free Pro tier includes full platform access, 100k logs, 1k scores, 5 datasets, 2 evaluators and 5 prompts
  • ✓Team tier adds unlimited datasets, evaluators and prompts plus private Slack and SOC 2 report
  • ✓Good provider coverage: OpenAI, Anthropic, OpenRouter, Groq, Fireworks, Together AI, Perplexity, Azure OpenAI and Bedrock
  • ✓Security signals include ISO 27001, SOC 2 and HIPAA references on the fetched page

Cons

  • ✗Branding appears as Respan on fetched pages, so teams should verify the current product/legal name
  • ✗Additional logs are listed at $8 per 100k logs, which can matter for high-volume apps
  • ✗Enterprise items such as HIPAA BAA, custom SLAs and dedicated support require sales

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🔒 Security & Compliance Comparison

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Security FeatureLangfuseKeywords AI / Respan
SOC2✅ Yes—
GDPR✅ Yes—
HIPAA✅ Yes—
SSO✅ Yes—
Self-Hosted——
On-Prem✅ Yes—
RBAC✅ Yes—
Audit Log✅ Yes—
Open Source✅ Yes—
API Key Auth✅ Yes—
Encryption at Rest✅ Yes—
Encryption in Transit✅ Yes—
Data ResidencyUS, EU, SELF-HOSTED—
Data Retentionconfigurable—
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Review LangfuseReview Keywords AI / Respan