Arize Phoenix vs Noveum AI: is observing your agents enough, or do you need them tested and fixed?

Most teams have scored traces running within 15 minutes. Install the SDK, wrap your LLM calls with the context manager, and 100+ scorers start running on every trace immediately. No eval infrastructure to configure, no expected answers needed, and no annotation work before you see real quality signal. In a June 2026 benchmark of eight LLM evaluation platforms, Noveum was also the only platform to ingest raw production traces with zero manual field-mapping, producing 440 ready-to-score items automatically without the operator mapping a single field.

NovaSynth is Noveum's synthetic testing system for AI voice and chat agents. Instead of waiting for real users to expose quality issues, you define realistic personas with specific backgrounds, tones, and goals, write test scenarios covering happy paths, edge cases, and adversarial inputs, and NovaSynth runs those conversations through your live agent at scale via voice, text, or phone. Every session is automatically scored with voice quality, safety, and telephony scorers. You find the failures before launch. Arize does not have a synthetic testing equivalent.

Yes. The Enterprise plan includes custom scorer development built around your product's specific evaluation logic. Domain-specific scorers sit alongside Noveum's 100+ built-in metrics and run in the same automated pipeline. A financial services team can score regulatory compliance. A healthcare team can score clinical accuracy. A voice AI team can score call-handling quality. You define what good looks like for your domain, and Noveum runs it at scale continuously without manual review cycles.

Arize Phoenix uses the Elastic License 2.0, not a permissive license like MIT or Apache 2.0. You can self-host and use it for free, but you cannot build a competing commercial service on top of the code. The managed cloud version, Arize AX, starts at $50 per month on the Pro plan with unlimited users.

Noveum's tiers are public, from free to $99 per month, with Enterprise on custom pricing. You pay for evaluation and testing output, not team size or trace volume. Arize AX Pro is $50 per month flat with unlimited users. AX Enterprise is custom and typically runs $50,000 or more per year at scale.

In a June 2026 benchmark across eight LLM evaluation platforms, Noveum achieved a composite accuracy score of 0.999 compared to Arize/Phoenix at 0.576. On faithfulness, both platforms are within the top statistical cluster, with Noveum at 89% recall / 10% false-alarm and Arize at 82% / 11%, so the confidence intervals overlap and neither can claim a clear faithfulness lead over the other. The more significant gap is on answer-relevance: Noveum's scorer correlated at 0.78 with the neutral reference while Arize's correlated at 0.06, meaning Arize's scorer could not reliably track whether an answer actually addressed the question on this dataset. On role-adherence across multi-turn conversations, Noveum scored 0.79 and Arize scored 0.59. Arize is the most balanced platform on tool-parameter scoring (100% recall, 81% specificity), which is worth noting if parameter correctness is your primary concern. Langfuse was not part of this benchmark.