LLM observability & evaluation · PromptLayer

PromptLayer

Prompt management and request-logging platform with versioning, playgrounds, and evaluation for LLM applications.

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PromptLayer centers on prompt lifecycle management: versioning prompts outside application code, testing them in a playground, and logging every request made against them so teams can compare how prompt changes affect real traffic. It layers evaluation on top, running scored 'eval executions' against datasets, and supports datasets for regression testing prompt changes before release. Its free tier is capped on users, monthly requests, and eval executions; Pro adds unlimited playgrounds and workspaces with pay-as-you-go overage, and Team raises those caps with a flat monthly fee plus lower per-transaction overage. Enterprise adds HIPAA/BAA support, flexible self-hosted or managed single-tenant hosting, and deployment approval workflows.

At a glance

Vendor PromptLayer
Pricing model Free tier + paid plans
Free tier Yes
Deployment Cloud, Self-hosted
Open source No
Best for Teams that want prompts version-controlled and tested outside of application code, with logging tied to each version.

Pricing

Free plan caps users, monthly requests, and eval executions; Pro and Team are monthly subscriptions with pay-as-you-go request overage; Enterprise is custom with self-hosted or single-tenant deployment.

Plan Price Notes
Free $0/month 5 users, 2.5k monthly requests, 1 workspace, 250 monthly eval executions, 10MB dataset max
Pro $49/month Unlimited playgrounds and workspaces, 150MB per dataset, $0.003 per transaction overage
Team $500/month 25 users, 100k+ monthly requests, 7.5k+ monthly eval executions, 1GB dataset max, $0.002/transaction overage
Enterprise Custom Custom usage limits, RBAC, deployment approvals, HIPAA/BAA, self-hosted or managed single-tenant

Prices read from the vendor's own page on September 21, 2026. Vendors change prices; check the source before you budget.

Features

  • Prompt versioning managed outside application code
  • Request logging tied to specific prompt versions
  • Prompt playground for testing and comparison
  • Dataset-based scored evaluation runs
  • Deployment approval workflows on Enterprise
  • Self-hosted or single-tenant deployment on Enterprise

Integrations

Profile last reviewed September 21, 2026

Alternatives

Humanloop Prompt management, evaluation, and observability platform aimed at product teams collaborating on LLM features with domain experts. LangSmith Tracing, evaluation, and deployment platform for LLM applications, built by the team behind LangChain and LangGraph. Lunary GDPR-focused LLM observability platform for tracing, prompt management, and human review, hosted in Europe or self-hosted.

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Terms to know

Data quality The degree to which data is accurate, complete, consistent and fit for the purpose it is being used for. Machine learning Building models that learn patterns from data to make predictions or decisions, rather than following hand-coded rules. Health Insurance Portability and Accountability Act (HIPAA) The U.S. law that sets privacy and security rules for protected health information handled by healthcare providers and insurers. LLM observability Monitoring a language model's live behavior in production, tracking its inputs, outputs, latency, cost, and failure patterns.

Related guides

How to choose an LLM observability tool Pick an LLM tool by whether you need tracing, scoring or a gateway first — most teams eventually need all three, rarely from one vendor.