PromptLayer review: Prompt versioning, evals and tracing for AI teams, with a free plan

What PromptLayer does

Stores and versions LLM prompts, runs evals against datasets, and traces production calls back to the prompt version that produced them.

PromptLayer is a platform where AI teams manage prompts, test them and watch how they behave in production. Prompts live in a central place instead of being spread through application code. Teams can edit them in a dashboard, add notes, compare versions, roll back, and publish to development or production. The vendor says people in product, marketing and content roles can change prompts directly, so engineers are not a bottleneck.

For testing, it supports dataset-backed evals that combine human review with automated graders. Evals can rerun whenever a prompt is updated, and prompts can be compared across models and parameters. On the monitoring side, it ties production traces and logs to prompt versions and reports cost, latency and token usage. Tracing integrations, such as for Claude Code and Pydantic AI, use OpenTelemetry rather than a proxy.

Pricing is freemium. The Free plan costs $0 per month and includes 5 users, 2.5k/month requests, 1 workspace and 250/month eval cell executions. Pro and Team add pay-as-you-go charges once usage passes the included amounts. Enterprise pricing is custom and adds options such as role based access controls, deployment approvals and HIPAA with BAA. The pricing page shows no yearly-billing prices and no trial.

• Visual prompt editor with versioning
• Diffs, notes and rollback of prompt changes
• A/B testing of prompt versions
• Dataset-backed evals with human and automated graders
• Regression evals on every prompt update
• Model and parameter comparison
• Production tracing with cost, latency and token stats
• OpenTelemetry-based trace ingestion

Our take

PromptLayer suits teams that want prompts, evals and production tracing in one workspace, especially where non-engineers need to adjust prompts without a code release. The Free plan, at $0 per month, lets a small group try it, though it caps requests at 2.5k/month and datasets at 10MB. Costs can rise beyond the included usage because overage is billed per transaction. Teams needing role based access controls, deployment approvals or a BAA must look at Enterprise, which has custom pricing. The official pages do not list apps for specific platforms.