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AI · head to head

PromptLayer vs Vellum

PromptLayer logo

PromptLayer

AI

Collaboration platform for prompt management, evaluation, and observability

From
Free
Rated
-
Full reviewWebsite
Vellum logo

Vellum

AI

Personalized AI assistant with persistent memory and autonomous action-taking

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: PromptLayer the free plan is capped at only 2,500 requests per month, quite limited for active production use.; Vellum pricing varies significantly by computational tier, making budget planning difficult
  • They diverge on capability: PromptLayer covers Visual prompt management, Vellum covers Persistent AI identity.

Where they differ

Only the attributes on which PromptLayer and Vellum actually diverge.

Attributes where PromptLayer and Vellum differ
AttributePromptLayerVellum
Pricing modelfreemiumFreemium with paid plans and pay-as-you-go credits
Platformsweb, apiWeb, macOS, iOS, Slack, Telegram, Terminal

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (AI).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in PromptLayer

  • Visual prompt management
  • Agent observability
  • Evaluations
  • Version control
  • Cost and latency monitoring
  • Agent workflow tracing

Only in Vellum

  • Persistent AI identity
  • Long-term memory
  • Email automation
  • Calendar management
  • Autonomous task execution
  • Multi-device synchronization
  • Custom plugins
  • Open-source deployment

What people use each for

The jobs each tool is most often brought in to do.

PromptLayer

  • Versioning and deploying prompts without code redeploysnot Vellum
  • Running evaluations with human review before production releasenot Vellum
  • Tracing multi-step agent workflows for debuggingnot Vellum
  • Monitoring LLM cost and latency by featurenot Vellum

Vellum

  • Personal productivity automation across email and calendarnot PromptLayer
  • CRM updates and pipeline managementnot PromptLayer
  • Expense report generation and managementnot PromptLayer
  • Document drafting and content creationnot PromptLayer
  • Meeting scheduling and calendar coordinationnot PromptLayer

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

PromptLayer

  • The free plan is capped at only 2,500 requests per month, quite limited for active production use.
  • The Team plan jumps to $500/month, a large step up from the $49/month Pro plan.
  • Overage transaction fees apply on top of subscription costs, which can make total spend less predictable.
  • Enterprise-grade features like HIPAA BAAs and custom deployment require contacting sales.

Vellum

  • Pricing varies significantly by computational tier, making budget planning difficult
  • Requires explicit permission for sensitive actions, limiting autonomy
  • Self-hosting option may intimidate non-technical users
  • Learning curve to develop customizations with plugins

Pricing, plan by plan

PromptLayer

Free
  • FreeFree
    • 5 users
    • 2,500 requests/month
    • 1 workspace
  • Pro$49/month
    • Unlimited playgrounds and workspaces
    • 150MB datasets
    • Pay-as-you-go overage at $0.003/transaction
  • Team$500/month
    • 25 users
    • 100k+ monthly requests
    • Webhooks
  • Enterprise$undefined/mo
    • Custom limits
    • Role-based access controls
    • HIPAA with BAA

Vellum

Free
  • FreeFree
    • Starter credits included
    • Basic features
  • Mighty$30/month
    • 1 vCPU, 2 GiB RAM
    • 10 GB storage
    • Included usage allowance
  • Super$100/month
    • 2.5 vCPU, 5 GiB RAM
    • 30 GB storage
    • Assistant email and subdomain
  • Ultra$200/month
    • 4 vCPU, 8 GiB RAM
    • 60 GB storage
    • Assistant email and subdomain

Which should you pick?

Choose PromptLayer if

  • You need visual prompt management.
  • You want to start without paying.
  • You work on web, api.
  • You also want agent observability.
PromptLayer review

Choose Vellum if

  • You need persistent ai identity.
  • You want to start without paying.
  • You work on Web, macOS, iOS, Slack, Telegram, Terminal.
  • You also want long-term memory.
Vellum review

Questions people ask

Is PromptLayer or Vellum better?
Neither clearly leads. PromptLayer starts at Free and Vellum at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, PromptLayer or Vellum?
PromptLayer starts at Free and Vellum at Free.
Does PromptLayer or Vellum run on more platforms?
PromptLayer runs on web, api. Vellum runs on Web, macOS, iOS, Slack, Telegram, Terminal.
Can I use PromptLayer for free?
Both have a free tier, so you can try either at no cost before committing.
What is PromptLayer best used for?
PromptLayer is most often used for versioning and deploying prompts without code redeploys, running evaluations with human review before production release, tracing multi-step agent workflows for debugging, monitoring llm cost and latency by feature. Of those, versioning and deploying prompts without code redeploys and running evaluations with human review before production release are not what Vellum is typically brought in for.
What can PromptLayer do that Vellum cannot?
PromptLayer covers Visual prompt management, Agent observability, Evaluations, Version control. Vellum covers Persistent AI identity, Long-term memory, Email automation, Calendar management.

Answered from the vendors’ own pages

PromptLayer: What does PromptLayer cost?

PromptLayer has a free plan, a Pro plan at $49/month, a Team plan at $500/month, and custom Enterprise pricing, with additional usage billed per transaction beyond plan limits.

Source
Vellum: How does Vellum protect my data privacy?

Vellum uses permission-based controls requiring explicit approval for sensitive actions. Data is encrypted and the option for self-hosting provides complete data control. Open-source deployment option allows hosting on your own infrastructure.

Source
PromptLayer: Is there a free plan, and what are its limits?

The Free plan includes 5 users, 2,500 requests per month, 1 workspace, 250 monthly eval cell executions, and datasets up to 10MB.

Source
Vellum: Can I use Vellum for business team collaboration?

Vellum is primarily designed as a personal assistant with persistent identity. For team collaboration, platforms like Lindy offer better multi-user features with shared credit pools and Slack workspace integration.

Source
PromptLayer: How is usage metered beyond the plan limits?

Additional usage is charged per transaction for requests, agent runs, and evaluation cell runs, at $0.003/transaction on Pro and $0.002/transaction on Team.

Source
Vellum: What does the free tier include?

Vellum offers free starter credits to begin using the platform. Beyond that, it operates on a pay-as-you-go credit model with paid tiers starting at $30/month for increased computational resources and bundled credits.

Source
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