Arize AX

Overview

Arize AX is an AI-agent observability and improvement platform for teams working to turn production behavior into better agents. It suits teams that need to investigate traces, evaluate changes, and monitor multi-agent systems. Its strongest case is a connected workflow from diagnosis to experimentation; its main constraint is that the lower-cost plans impose firm trace, ingestion, and retention caps.

Key features

Signal surfaces important issues, investigates root causes, and generates fixes ready for review. Managed Agents can investigate failing traces, fix repository bugs, automate recurring checks, or be built from scratch. That breadth makes AX relevant to teams that want agent investigation and operational tasks in the same platform, though the plans’ Signal issue limits matter if many problems arrive each month.

Swarm Observability tracks the status and performance of an entire agent swarm in real time. Agent-as-a-Judge uses agent telemetry to create scalable evaluations that can surface failures teams did not already know to check for. End-to-end experiments help validate agent changes before teams rely on them. Together, these tools address monitoring, evaluation, and iteration rather than tracing alone.

AX supports tracing integrations for OpenAI, Anthropic, Google GenAI, Amazon Bedrock, LangChain, LangGraph, LlamaIndex, CrewAI, and Vercel AI SDK. Its use of OpenInference conventions and OpenTelemetry for instrumentation is a practical fit for teams adopting those tracing standards. The platform also includes LLM and agent tracing, retrieval tracing, evaluations, prompt management, and token cost tracking.

Pricing

AX Free costs nothing. It includes 10 Signal issues/month, 25k trace spans/month, 1 GB ingestion/month, 15-day retention, SaaS deployment, unlimited users and evaluations, and community troubleshooting support. This is a useful starting point for a small workload or an initial evaluation, but the short retention and modest monthly quotas may limit ongoing production analysis.

AX Pro costs $50 a month, billed $50 per month. It raises the limits to 25 Signal issues/month, 50k trace spans/month, 10 GB ingestion/month, and 30-day retention, while keeping SaaS deployment and unlimited users and evaluations. Email support is included. Pro is the more workable option for teams with sustained but bounded usage; it still caps issues, spans, ingestion, and retention.

AX Enterprise has custom pricing and includes unlimited Signal, custom trace-span, ingestion-volume, and retention terms, SaaS or self-hosted deployment, unlimited users and evaluations, and dedicated support. It is the natural fit for organizations that need flexible capacity or infrastructure control, but requires a custom quote. AX Free and Pro list US, EU, or CA data regions.

Platforms

AX is available by API, as a web platform, and as a self-hosted deployment. Self-hosting keeps observability data, authentication, APIs, and the user interface inside the customer’s infrastructure, with air-gapped deployment available. That makes Enterprise a meaningful option for teams with strict infrastructure requirements; Free and Pro are SaaS-only.

Who it's for

Arize AX is best suited to teams operating AI agents that need to connect trace investigation with evaluation and controlled experimentation, particularly when they manage agent swarms or want to act on production failures. Teams with low volumes can begin on Free, while those needing higher quotas can move to Pro. It is a weaker fit for teams whose workload exceeds Pro’s fixed limits but does not justify Enterprise, or those that require self-hosting on a lower-cost plan.

Pros and cons

• Pros: Combines trace investigation, review-ready fixes, evaluations, swarm monitoring, and experiments, so teams can use one platform across several stages of agent improvement.
• Pros: Broad provider and framework integrations, plus OpenInference and OpenTelemetry conventions, support varied tracing setups.
• Pros: Enterprise offers self-hosting and air-gapped deployment, while keeping observability data and core platform components in the customer’s infrastructure.
• Cons: Free and Pro both cap Signal issues, trace spans, ingestion, and retention, which can restrict teams with heavier or longer-running workloads.
• Cons: Self-hosting is only included with custom-priced Enterprise, so teams needing infrastructure control cannot use the fixed-price plans.

Alternatives

Consider Opik if open-source observability and evaluation code that can be downloaded and run locally is a priority; it also has a free plan and free trial. W&B Weave is another freemium option, with a free tier that includes 1 GB/mo of data ingestion, 5 GB/mo of storage, and evaluations, tracing, and scorers. Choose Langfuse for a free Hobby plan with 50k units/month, 30 days of data access, and two users, or a Core plan at $29 a month billed monthly.

LangWatch is an alternative freemium, open-source option under Apache 2.0. Agenta offers a free Hobby plan with two team members, 5,000 agent runs/month, 20 evaluations/month, and one-week trace retention. Braintrust has a free Starter plan with 1 GB processed data, 10,000 scores, 14-day retention, and unlimited users, projects, and datasets. Helicone is a freemium, open-source alternative with a free trial. Galileo is an alternative with a Pro plan at $100 a month, billed yearly, including 50,000 traces per month.

Browse AI LLM Observability Tools, Model Monitoring Software, LLM Observability Tools, AI Agent Observability Tools, or Machine Learning Model Monitoring Software to compare related categories.

Verdict

Choose Arize AX if your team wants to trace agent behavior, investigate failures, build evaluations, and test improvements in one platform. Its range is compelling for agent operations, and Enterprise adds substantial deployment flexibility. Look elsewhere if you need self-hosting without custom pricing, or if the fixed Free and Pro quotas do not match your workload.