Vellum Review
An end-to-end LLM development platform that bundles prompt engineering, a visual workflow builder, an evaluation framework, RAG retrieval and production monitoring for teams shipping AI features.
Is Vellum Worth It?
Vellum is worth it for teams building and shipping LLM features that need prompt engineering, workflows and evaluation in one platform. The platform combines Prompt Studio, a visual workflow builder, an evaluation framework and RAG retrieval that competing point tools split across separate products. A free tier covers light use, but the jump to the $500/mo Pro plan is steep for mid-size teams. Teams that build once and ship to production get the most value from Vellum’s all-in-one approach.
About Vellum
Vellum is an end-to-end LLM development platform that lets teams engineer prompts, build workflows, evaluate outputs and deploy AI features to production from one workspace. Vellum AI, Inc. operates the platform, a company backed by Y Combinator in the W2023 batch and founded by Akash Sharma (CEO), Noa Flaherty and Sidd Seethepalli.
Vellum works in three stages. Teams build and compare prompts in Prompt Studio, then chain those prompts into a multi-step workflow that carries business logic and API calls, and finally evaluate outputs against test cases before deploying the workflow behind a versioned endpoint. Vellum adds observability and monitoring on top, so production traffic feeds back into the same platform that built the feature.
Model-agnostic orchestration
Vellum stays model-agnostic and connects to major model providers, which lets teams swap or compare models without rebuilding a workflow. This positions Vellum as an orchestration layer between raw model APIs and a shipped product, bundling prompt engineering, a workflow builder, an evaluation framework, RAG retrieval through Vellum Search, and production monitoring in one place.
Vellum suits AI engineering teams, product managers and non-technical builders, and regulated enterprise organizations. Engineers get a workflow builder, API endpoints and version control that fit an existing process, product teams get plain-English prompt editing and collaboration, and regulated firms get VPC deployment, HIPAA compliance and self-hosted options.
Our Verdict
Pros
- All-in-one platform across build, evaluate and deploy
- Model-agnostic across major providers
- Collaboration for technical and non-technical users
- Version control on prompts and workflows
- Managed RAG and evaluation built in
Cons
- Steep price jump from free to $500/mo Pro plan
- Execution caps limit high-volume free use
- Learning curve across the full workflow builder
- Separate model-provider API costs on top of the plan
- Enterprise-grade controls gated to custom pricing
How It Works
Sign up
Create a workspace on the Vellum AI website.
Connect a model provider
Add an API key for your chosen model.
Build a prompt
Draft and chain it into a workflow in Prompt Studio.
Evaluate the workflow
Test it against test cases in the evaluation framework.
Deploy and monitor
Publish the workflow behind a versioned endpoint and track production traffic.
Vellum Features
Prompt Studio
Draft, version and compare prompts side by side across models in one playground.
Workflow Builder
Chain prompts, logic and API calls into multi-step AI features on a visual canvas.
Evaluation Framework
Run regression tests and LLM-based grading against defined test cases before and after deployment.
Vellum Search
Ground prompts in your own documents with built-in chunking, embedding and retrieval for RAG.
Deployment & Monitoring
Publish workflows behind versioned endpoints and track production inputs, outputs and latency.
Vellum Pricing
- 5,000 prompt executions/day
- 250 workflow executions/day
- Role-based access control
- Production monitoring
Who Is Vellum Best For?
Ship LLM features to production with a workflow builder, API endpoints and version control.
Edit prompts in plain English and assemble logic without writing code.
Get HIPAA compliance, VPC deployment and self-hosted options for strict data control.
Vellum Alternatives
| Tool | Best for | Price | Notes | Compare |
|---|---|---|---|---|
| LangSmith | LangChain and LangGraph users | Usage-based | Yes | vs → |
| Braintrust | Evaluation-first teams | Usage-based | Yes | vs → |
| Langfuse | Open-source and self-host | Free (self-host) | Yes (open source) | vs → |
| Vellum — this review | All-in-one build and deploy | $500/mo | Yes |
Vellum vs LangSmith
Vellum builds, evaluates and deploys LLM features in one visual platform, while LangSmith centers on tracing and evaluation for LangChain and LangGraph applications. Vellum favors teams that want a full visual build surface, and LangSmith favors teams already committed to the LangChain stack.
Vellum FAQ
Is Vellum free?
Vellum is free on a limited tier, not fully free. The free plan covers 50 prompt executions per day and light use, then the Pro plan starts at $500/mo.
How much does Vellum cost?
Vellum costs $500/mo on the Pro plan, with Enterprise custom-priced. Model-provider usage is billed separately on top of the plan fee.
What is Vellum AI?
Vellum AI is an end-to-end LLM development platform that lets teams engineer prompts, build workflows, evaluate outputs and deploy AI features to production from one workspace.
Is Vellum safe?
Vellum is safe for production use, holding SOC 2 Type 2 and HIPAA compliance with VPC and self-hosted deployment options for sensitive workloads.
Ready to try Vellum?
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