Arize AX Review 2026: Unlimited Evals, $50 Step
Verdict: Arize AX is the value pick for teams that have grown past hobby-scale tracing but do not want to spend $249 a month to get there: $50/mo for 50K spans, 10 GB of ingestion, 30-day retention, and unlimited users and evals on every tier including free. It is also the only option here with a credible fully local story - Arize Phoenix is open source and free, though your own AX data only stays in-house at Enterprise. Pick Langfuse for a similar price curve with more mature cloud tiers, LangSmith for platform breadth, or Braintrust if published per-1K score pricing is what you need to forecast against. 4.0/5
Our six-dimension assessment
We evaluate every tool on the same six dimensions so scores stay comparable across categories: core features, ease of use, stability, collaboration, localization, and value for money. Arize AX scored 4/5 overall.
The core feature set of Arize AX is what most buyers evaluate first. Our score of 4/5 reflects a mature, complete implementation.
A 3/5 for ease of use means the learning curve is real and should be budgeted for.
Stability at 4/5 reflects consistent performance and few reliability concerns in testing.
Collaboration scores 3/5 — the weakest area for team use; solo workflows are the better fit.
Localization at 2/5 covers mostly English-first workflows with limited locale coverage.
Value for money scores 5/5 — the pricing is competitive against direct alternatives.
Pricing and plans
AX Free $0 (10 signals/mo, 25K spans/mo, 1 GB/mo, 15-day retention) · AX Pro $50/mo (25 signals/mo, 50K spans/mo, 10 GB/mo, 30-day retention) · Enterprise custom (unlimited signals/spans, self-hosted option) · Phoenix open source free
| Item | Detail |
|---|---|
| Free plan | Yes |
| Paid plans from | $50/mo (AX Pro) |
| Billed monthly | AX Free $0 (10 issues/mo, 25K trace spans/mo, 1 GB ingestion/mo, 15-day retention, SaaS) · AX Pro $50/mo (25 issues/mo, 50K spans/mo, 10 GB/mo, 30-day retention) · Enterprise custom (unlimited issues and spans, self-hostable) |
| Billed annually | No published annual rate; a separate startup pricing track exists on the pricing page |
| Billing notes | Billed on signals, spans, ingestion volume and retention rather than seats - users and evals are unlimited on every tier; self-hosted deployment is Enterprise-only, while the open-source Phoenix platform is free and local |
| Last verified | 2026-10-03 |
Billed on signals, spans, ingestion volume and retention rather than seats - users and evals are unlimited on every tier; self-hosted deployment is Enterprise-only, while the open-source Phoenix platform is free and local — verified on the official pricing page (2026-10-03).
Arize AX offers a genuinely free entry point, which makes it low-risk to trial before committing budget.
Who is Arize AX for?
It is also the only option here with a credible fully local story - Arize Phoenix is open source and free, though your own AX data only stays in-house at Enterprise.
If your team matches the profile above — LLM Observability use cases where a free entry helps you de-risk the decision — Arize AX is worth a structured trial. If not, the comparison below points to alternatives.
Strengths (per official docs)
- Unlimited users and unlimited evaluations on every tier, including the free one - the only cluster member that never charges for seats
- $50/mo is the cheapest paid step in the set, undercutting Braintrust Pro by 5x
- Arize Phoenix is a genuinely free, open-source, local-first platform for tracing and evaluation with no account required
- Session-level and multi-modal tracing (image, voice, PDF), agent trajectory visualizations and online/offline evals are unlimited on all tiers
Limitations (per official docs)
- The free tier is narrow - 10 signals a month and 25K spans, so production volume will not fit
- Self-hosted deployment is Enterprise-only; the free local option is the separate Phoenix project, not AX itself
- SOC 2 Type II, SSO, audit logs, HIPAA and data-region choice start at Enterprise
- Support is community on the free tier and email on Pro, with SLAs reserved for Enterprise
Scorecard
The value pick: unlimited users and unlimited evals on every tier, a $50/mo paid step that undercuts Braintrust by 5x, and a genuine free open-source sibling (Phoenix) if you want local tracing with no account at all. The trade-offs are real - the free tier is capped at 10 signals and 25K spans, and self-hosting your own data only arrives at Enterprise, so privacy-sensitive teams pay to talk sales.
Evidence: verified against official documentation & pricing pages arize.comarize.com (checked 2026-10-03)
Frequently asked questions
Is Arize AX worth it in 2026?
Based on our six-dimension scoring (4/5 overall), Arize AX is a strong, well-rounded pick in the LLM Observability space. The verdict above summarizes where it wins and where to be careful.
How does Arize AX compare to alternatives?
See our LLM Observability comparison for a side-by-side rating, pricing, and free-tier review.
Does Arize AX have a free plan?
Yes — Arize AX offers a free tier, which is the best way to validate it before paying.
How credible is this review?
How this review was made: for Arize AX, the evidence is based on official documentation. See our methodology for details.