Arize vs PromptLayer (2026): Pricing, Features & Which to Choose

Who comes out ahead

Based only on the facts in our directory. The right pick still depends on the job you need done.

Lower starting price
Not comparable
Not comparable: Arize does not list a price
Free plan
PromptLayer
Only PromptLayer has one
Higher rating
Arize
4.2 against 3.9
Same job?
Yes
Both are AI Infrastructure & Agent Tooling tools

Side by side

Compared on	Arize	PromptLayer
Our rating	4.2Better	3.9
Starts at	Not listed	Free
Free plan	No	YesBetter
Category	AI Infrastructure & Agent Tooling	AI Infrastructure & Agent Tooling
Plans	See pricing	Free
Key features	Started in traditional ML drift and performance monitoring before expanding to LLMs Open-source Arize Phoenix framework for generative AI observability LLM evaluation and prompt versioning through a Prompt Hub Tracing built for multi-step, conversational agent applications $131M raised, valued at over $1 billion as of its February 2025 Series C	Prompt registry with versioning Evaluation harness for regression testing prompts Request observability and tracing Visual editor for non-engineers Collaboration without codebase access
Pros	Covers both traditional ML monitoring and generative AI evaluation in one platform Open-source Phoenix framework gives a free, inspectable starting point before adopting the full platform Billion-dollar valuation and $131M raised signal real staying power	Lets domain experts improve prompts without a deploy cycle Evaluations prevent well-meaning edits silently breaking cases Covers management, testing and observability rather than one slice
Cons	Enterprise pricing isn't published, so budgeting requires a sales conversation Broad scope spanning classic ML and generative AI can mean more setup than a single-purpose LLM tool Competes directly against well-funded peers like Braintrust and LangSmith in a crowded observability market	Overhead is hard to justify for a single-developer project Another dependency in the request path to monitor Meaningful evaluation still requires you to build the test cases
Company	Arize AI, founded 2020	PromptLayer

Prices come from each vendor's pricing page, last checked 20260901. Check the vendor before you buy.

FAQ

Questions people ask

Is Arize better than PromptLayer?

In our reviews Arize scores 4.2 and PromptLayer scores 3.9. The better pick depends on the job. Arize: Grew from traditional ML monitoring into a $1B+ AI engineering platform for evaluating agents in production. PromptLayer: Prompt registry, evaluation harness and observability in one place - so domain experts can change prompts without touching your codebase.

Which is cheaper, Arize or PromptLayer?

Arize: see pricing. PromptLayer: free.

Do Arize and PromptLayer have free plans?

Only PromptLayer has a free plan.

More comparisons

Arize compared with

All Arize alternatives

PromptLayer compared with

All PromptLayer alternatives