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The 2026 AI Eval Platform
Benchmarks

Which AI eval platform actually catches failures without flagging good answers?

What we found

Scroll through each dimension. Five cards, one story.

Composite

Overall ranking

Equal-weighted average across five comparable dimensions. Balance beats winning one column.

Full section →
Noveum
0
DeepEval
0
Arize / Phoenix
0
Galileo
0
Ragas
0
Maxim
0
Faithfulness

Recall vs calibration

Top-left on the scatter wins. Catch failures with high recall without flagging good answers.

Full section →
unusable for auto-gating60%80%100%0%20%40%Noveum 89% · 10%Ragas 94% · 37%
Scorer trap

Opposite verdicts

The scorer you enable can matter more than the vendor you choose.

Full section →
autoevals ClosedQA
8%
autoevals.ragas
66%
Latency

Judge speed

Noveum returns a verdict in 0.59s, 2 to 27 times faster than the field.

Full section →
Noveum
0
Arize
0
Braintrust
0
DeepEval
0
Ragas
0
Patronus
0
Consistency

Cross-dimension balance

Bright, even rows beat tall peaks and holes. Consistency is the rarest property in the study.

Full section →
faithF1ansRelctxReltoolSel
Noveum1.001.000.991.00
DeepEval0.720.050.971.00
Arize / Phoenix0.870.080.910.89
Galileo0.920.000.83NA

How it works

A real agent runs adversarial conversations. Each platform scores with its own native scorers, no cheat sheet. Five steps from stress test to published, reproducible scores.

RAG agent

LangGraph chatbot on gpt-4.1-mini over 599 documentation chunks. Grounded and deliberately ungrounded variants.

❯_

100 conversations

440 assistant turns · 131 genuine hallucinations · 9 adversarial scenario families

⦿

Opus-4.8 referee

Claude Opus-4.8 labels every turn. Never shown to any platform.

8 native scorers

Reference-free · each platform's documented best setup

Published scores

Bootstrap 95% CIs, 2,000 resamples · fully re-derivable

Noveum's method beat ClosedQA on the identical GPT judge: 82% vs 55% recall. The difference is the method, not the model.

Real agent

LangGraph RAG chatbot on gpt-4.1-mini. Skips retrieval on 53% of turns. 78% of its hallucinations came with no retrieved context at all.

⦿

Neutral referee

Claude Opus-4.8 labels all 440 turns for hallucination, quality, relevance, and role adherence. Never an input to any platform.

Statistics, not vibes

Bootstrap 95% CIs on every rate. Paired significance tests on close calls. Ties reported as ties.

Overall ranking

Who scores best across all dimensions on average? The composite is an equal-weighted average of the five dimensions that share a comparable metric. Balance beats winning one column.

Noveum
0
DeepEval
0
Arize / Phoenix
0
Galileo
0
Ragas
0
Maxim
0
Braintrust
0
Patronus
0

Hosted-only scorers are excluded from a platform's average rather than counted against it.

Clear separation at the summit.

Noveum 0.999 vs DeepEval 0.650. The composite gap at the top is decisive.

Balance beats one dimension.

Only Noveum scores high across all five composite dimensions at once.

No platform owns every column.

Ragas leads context-relevance. Braintrust leads faithfulness false-alarm rate. Arize has the best-balanced tool-argument profile. Noveum's headline is balance.

Recall vs calibration

Faithfulness balances hallucination recall against false-alarm rate. For unsupervised gating, false alarms decide usability. Noveum leads on balance at 89% recall and 10% false-alarm; Ragas catches more but flags 37% of good answers.

Recall vs false-alarm · 440 turnsunusable for auto-gating40%60%80%100%0%10%20%30%40%Top-left winsbetterFalse-alarm rate (lower is better ←)Recall (higher is better ↑)Braintrust 80% · 8%Arize 82% · 11%DeepEval 73% · 10%Patronus 48% · 18%Noveum 89% · 10%Ragas 94% · 37%

01. Best balance

Highest F1 and strongest quality correlation across faithfulness scorers.

F1 composite84%

02. Calibration leader

Braintrust ClosedQA posts the lowest false-alarm rate in the study.

False-alarm rate8%

03. High recall, unusable

Ragas catches the most hallucinations but flags a third of good answers.

Hallucination recall94%

04. Purpose-built, missed

Patronus Lynx scores lowest on conversational fabrications it was built for.

Fabrication recall48%

The top three recall scores (Noveum, Braintrust, Arize) overlap within their confidence intervals. Under the stronger paired test, Noveum's edge over Braintrust is significant while its edge over Arize is borderline. We report the cluster as a statistical tie on purpose.

Full report

Unlock the complete benchmark

Go deeper with the 22-page report and buyer's guide — six job-to-shortlist maps built directly from the data.

Same data, opposite verdicts

The scorer you enable can swing results more than the vendor you pick. On identical turns, Braintrust swings 58 points between scorers; DeepEval's dedicated metric catches 1% vs 73% for GEval. Audit which scorer is actually enabled.

autoevals ClosedQA
0
autoevals.ragas
0

58-point swing on identical turns.

GEval config
0
FaithfulnessMetric
0

Dedicated metric: 1%. GEval: 73%.

Recall
0
False-alarm
0

High recall, nearly half of good answers flagged.

01. Scorer swing

Same vendor, same data — opposite verdicts from scorer choice alone.

False-alarm delta58 pts

02. Metric mismatch

FaithfulnessMetric catches almost nothing; GEval catches 73% on identical turns.

Recall delta72 pts

03. Over-flagging

Maxim catches nearly everything but flags almost half of good answers.

Good-answer flags48%

Specialization patterns

Aggregate recall hides specialization. Fabricated code APIs are hardest (21–88% recall); chained facts are solved at 100%. Prompt injection inverts rankings — chunk-level scorers lead, while Noveum peaks on out-of-scope fact pressure.

0%Ragas
0%Noveum
0%Braintrust
0%Arize
0%DeepEval
0%Patronus
0%Noveum
0%Ragas
0%Arize
0%Braintrust
0%DeepEval
0%Patronus

01. Code APIs hardest

Invented SDK methods slip through most often. Noveum lands at 75%.

Noveum recall75%

02. Chained facts solved

Every general-purpose judge hits 100% on chained-fact synthesis.

General judges100%

03. Pressure facts

Noveum posts perfect recall on out-of-scope fact pressure.

Out-of-scope recall100%

04. Injection inverts

Chunk-level scorers lead; Noveum's weakest substantial family at 55%.

Noveum recall55%

Retrieval and answers

RAG evaluation splits into context-relevance (retrieval quality) and answer-relevance (did the response address the question). Ragas leads context at r = 0.95; Noveum separates answer-relevance at r = 0.78 while peers cluster near zero.

0Noveum
0Ragas
0DeepEval
0Arize
0Braintrust

Context relevance is the field's strongest dimension and it is not a Noveum win. Ragas leads at r = 0.95 with Noveum essentially tied at 0.945 (held-out validated at r = 0.93 on 280 turns its scorer never saw in development). Nearly half of all turns retrieved nothing, and the strong scorers all treat an empty retrieval as a true zero.

0Noveum
0Ragas
0Braintrust
0Arize
0DeepEval

Answer relevance separated the field sharply. Noveum correlates at r = 0.78 while every other native scorer lands between 0.04 and 0.27. One caveat: this dimension had low variance in the gold labels, so it carries less statistical power than the others.

Right tool, real arguments

Agent failures are wrong tool choice or fabricated arguments in otherwise plausible calls. Only four platforms ship native tool-call scorers. Noveum and DeepEval tie on selection; Arize balances fabricated-argument detection best.

0%Noveum
0%DeepEval
0%Arize
0%Ragas
0%Noveum
0%Arize
0%DeepEval
0%Ragas

01. Tool selection

Noveum and DeepEval tie at perfect specificity on tool choice.

Specificity100%

02. Fabricated arguments

Arize posts the best balance; Noveum is the most cautious autonomous gate.

Arize specificity81%

03. No universal profile

Gates want low false alarms; regression suites want exact-match recall.

Use-case split2 modes

Staying in character

Role-adherence asks whether the agent held persona across multi-turn pressure. Only Noveum and DeepEval ship native scorers. Noveum leads at r = 0.79; GPT-tier judges cluster at 0.56–0.68.

Noveum
0
DeepEval
0
Galileo
0
Ragas
0
Maxim
0
Patronus
0
Arize
0
Braintrust
0

Noveum's native conversational scorer leads at r = 0.79 and separates good agents from bad ones most cleanly. The GPT-tier scorers cluster at r = 0.56 to 0.68. On this task, the judge model dominates the plumbing unless the scorer is genuinely specialized.

Judge speed

For realtime gates and high-volume scoring, a slow judge is a non-starter regardless of accuracy. Noveum 0.59s, 2 to 27 times faster than the field.

Noveum
0
Arize
0
Braintrust
0
DeepEval
0
Ragas
0
Patronus
0

Latency here is the local judge-model call, measured identically for every platform, not a hosted-API round-trip. A 13 to 16 second judge (Ragas, Patronus) cannot sit in a request path.

Galileo Luna (cheapest)
0
BYO gpt-4.1-mini
0
Noveum recommended judge (raw tokens)
0
Noveum bundled credit
0
Patronus (most expensive)
0

Accuracy and speed together leave exactly one point on the frontier: Noveum is more accurate and faster than every other platform. Coverage is the multiplier everyone forgets. Scoring six dimensions costs six scorer-calls per turn, so a calibrated, cheap judge compounds.

High and flat

A platform can win one dimension and still be a poor general-purpose evaluator if it is spiky. Normalized scores across five dimensions. Low spread means balanced performance.

NA means the platform ships a dedicated scorer that runs hosted or server-side (excluded, not zeroed). A 0.00 cell is the worst measured value or a confirmed capability gap. The five middle columns are each platform's normalized scores per dimension. The final σ column is the spread of those five scores, not a score itself. Noveum's σ of 0.002 means its five dimension scores are all near 1.0 with almost no gap between them. Low σ at a high mean is reliable everywhere, unlike flat-at-the-bottom Patronus. Noveum's overall score is 0.999, never 0.002.

Faith F1Ans-relCtx-relTool-selRole-adhσ
Noveum1.001.000.991.001.000.002
DeepEval0.720.050.971.000.520.348
Arize / Phoenix0.870.080.910.890.130.385
Galileo0.920.000.83NA0.480.362
Ragas0.490.351.000.130.480.287
Maxim0.890.050.00NA0.440.358
Braintrust0.900.310.160.000.000.333
Patronus0.000.000.000.000.390.157
0.999
Noveum score

The headline number. Use this for any bar or chart.

0.002
Noveum spread (σ)

Consistency only. Lower is better. Never use as the score.

Noveum is the only platform both high and flat across every measured dimension, with a mean of 0.999 and a spread of just 0.002. Every other competitive platform carries at least one tall peak and one hole: DeepEval's near-zero answer relevance, Braintrust's missing tool and conversational scorers, Galileo's and Maxim's faithfulness over-flagging. If one platform must cover a whole agent, consistency is the number to check.

Frequently asked questions

Reproducible · Open data

Download the full report

22-page benchmark plus buyer's guide. Every score reproducible.

22 pages · 8 platforms · 6 dimensions · 2,000-resample CIs · public harness