AI · head to head
Vellum vs Arize AI

Vellum
AI
Personalized AI assistant with persistent memory and autonomous action-taking
- From
- Free
- Rated
- -

Arize AI
AI
AI engineering platform for observability and evaluation of agents and LLM apps
- From
- Free
- Rated
- -
The short version
- Each has a real cost: Vellum pricing varies significantly by computational tier, making budget planning difficult; Arize AI the free plan caps trace spans at 25,000 per month with only 15 days of retention.
- They diverge on capability: Vellum covers Persistent AI identity, Arize AI covers End-to-end tracing.
Where they differ
Only the attributes on which Vellum and Arize AI actually diverge.
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 Vellum
- Persistent AI identity
- Long-term memory
- Email automation
- Calendar management
- Autonomous task execution
- Multi-device synchronization
- Custom plugins
- Open-source deployment
Only in Arize AI
- End-to-end tracing
- Evaluation framework
- Prompt testing and improvement
- Alyx AI engineering agent
- Custom dashboards
- Data warehouse integrations
What people use each for
The jobs each tool is most often brought in to do.
Vellum
- Personal productivity automation across email and calendarnot Arize AI
- CRM updates and pipeline managementnot Arize AI
- Expense report generation and managementnot Arize AI
- Document drafting and content creationnot Arize AI
- Meeting scheduling and calendar coordinationnot Arize AI
Arize AI
- Tracing and debugging production AI agentsnot Vellum
- Running large-scale evaluations across traces and sessionsnot Vellum
- Improving prompts before production rolloutnot Vellum
- Storing and querying GenAI traces alongside a data warehousenot Vellum
Where each one falls short
Documented limitations, not opinions. Every one is a constraint you would hit in normal use.
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
Arize AI
- The free plan caps trace spans at 25,000 per month with only 15 days of retention.
- Self-hosted deployment and Data Fabric integration are restricted to the custom-priced Enterprise tier.
- Pricing beyond the $50/month Pro plan requires a custom quote, making cost planning less transparent at scale.
- Advanced compliance features like HIPAA are only available on Enterprise.
Pricing, plan by plan
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
Arize AI
Free- AX FreeFree
- 25k trace spans/month
- 1 GB storage/month
- 15-day retention
- AX Pro$50/month
- 50k trace spans/month
- 10 GB storage/month
- 30-day retention
- AX Enterprise$undefined/mo
- Custom trace spans, storage, and retention
- SaaS or self-hosted deployment
- Managed agents and Data Fabric
Which should you pick?
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.
Choose Arize AI if
- You need end-to-end tracing.
- You want to start without paying.
- You work on web, api.
- You also want evaluation framework.
Questions people ask
- Is Vellum or Arize AI better?
- Neither clearly leads. Vellum starts at Free and Arize AI at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
- Which is cheaper, Vellum or Arize AI?
- Vellum starts at Free and Arize AI at Free.
- Does Vellum or Arize AI run on more platforms?
- Vellum runs on Web, macOS, iOS, Slack, Telegram, Terminal. Arize AI runs on web, api.
- Can I use Vellum for free?
- Both have a free tier, so you can try either at no cost before committing.
- What is Vellum best used for?
- Vellum is most often used for personal productivity automation across email and calendar, crm updates and pipeline management, expense report generation and management, document drafting and content creation. Of those, personal productivity automation across email and calendar and crm updates and pipeline management are not what Arize AI is typically brought in for.
- What can Vellum do that Arize AI cannot?
- Vellum covers Persistent AI identity, Long-term memory, Email automation, Calendar management. Arize AI covers End-to-end tracing, Evaluation framework, Prompt testing and improvement, Alyx AI engineering agent.
Answered from the vendors’ own pages
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.
SourceArize AI: What does Arize AX cost?
Arize AX offers a free plan, a Pro plan at $50/month, and a custom-priced Enterprise plan, with pricing based on trace spans, storage, and retention needs.
SourceVellum: 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.
SourceArize AI: Is there a free plan, and what are its limits?
The AX Free plan includes 25,000 trace spans and 1 GB of storage per month with 15-day retention, plus unlimited users, evaluations, and experiments.
SourceVellum: 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.
SourceArize AI: What deployment options are available?
Free and Pro plans are SaaS-only, while Enterprise customers can choose SaaS or self-hosted deployment with custom SLAs.
SourceRelated pages
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