AI humanizers compared directly
Looking for a RewriteAI alternative? This direct comparison separates simple rewriting from dependable text quality and keeps the missing tenth RewriteAI output visible.
Internal benchmark · July 28, 2026. The same source texts, blinded review, and separate checks for meaning, language, length, and citations.
The result in one sentence
+15.73RewriteAI remained solid on language and length but produced only nine usable outputs. Certentis scored substantially higher on quality, semantic fidelity, and citation preservation.
Overall quality
Quality scale 40–100 · truncated axis
Semantic fidelity
Exact citations
Distance from source quality
Best version in blinded review
Product profile and terms
The benchmark measures output quality. This section adds the current product context: modes, limits, languages, platforms, and publicly documented safeguards.
Certentis in everyday use
A controlled humanizer for academic and professional texts, with separate AI analysis and a traceable history.
Certentis does not optimize for a scanner classification alone. Automatic checks cover language, length, rewriting, and recognized protected content. Meaning is assessed in the archived benchmark and still requires your final review.
Product profile
An English-focused paste-and-rewrite humanizer with Basic and Advanced engines, multiple variants, and a public API.
RewriteAI is simple and inexpensive to try. Multilingual or citation-sensitive texts require more manual review because English is explicitly described as its strongest language and citation protection is presented only as a marketing claim.
| Features and terms compared | Certentis | RewriteAI |
|---|---|---|
| Price and trial access | Credits; Humanizer uses 1 credit per input word. Internal retries within one process do not consume additional credits. | Free: 500 words/month. Homepage: Basic $9.99, Pro $24.99, Max $49.99 monthly; individual subpages show different figures. |
| Input limit | Up to 30,000 characters and 3,000 words per input in the current web app. | Depending on the plan, 300, 750, 1,500, or 3,000 words per input according to the homepage. |
| Languages | Automatic language detection; the rewrite remains in the original's dominant language. | According to the provider, other languages work, but the model is optimized for English. |
| Modes and workflow | One controlled mode with local checks followed by an analysis report. | Paste text, choose an engine or mode, generate multiple variants, and copy an output. |
| Academic texts and citations | Existing citation blocks are protected and checked for completeness after the rewrite. | Advanced is marketed for academic texts and citation preservation; no technical protection or completeness check is explained. |
| Platforms and API | Web app with history, AI analysis, and plagiarism checking in the same workspace. | Web app and REST API. |
The homepage and AI Humanizer subpage conflict on prices and limits. Terms should be checked directly at checkout.
Official product sources
Provider information verified on August 3, 2026
Prices and features may change. Provider claims were not treated as evidence of quality; only the separate Certentis benchmark is used for that assessment.
The comparison at a glance
A single AI detector score cannot decide the result. A useful rewrite must also remain natural, faithful to the source, stable in language, and dependable in its citations.
| Metric | Certentis | RewriteAI | Stronger result |
|---|---|---|---|
| Overall quality | 85.4 | 69.67 | Certentis |
| Semantic fidelity | 91.7 | 73.0 | Certentis |
| Exact citations | 8/10 | 4/9 | Certentis |
| Correct language | 10/10 | 9/9 | Tie |
| Word ratio | 0.98 | 1.08 | Certentis |
| Human + Mixed | 92.96% | 78.41% | Certentis |
Certentis: 10 usable cases · RewriteAI: 9 usable cases
Overall quality
The blinded review scored every output separately. These profiles show whether a tool merely sounds fluent or also preserves structure, precision, evidence, and meaning.
RewriteAI remained respectable in grammar and readability, but lost ground in precision, academic style, citation integration, and semantic fidelity.
| Metric | Certentis | RewriteAI |
|---|---|---|
| Grammar & language | 93.9 | 82.56 |
| Clarity & readability | 91.8 | 76.67 |
| Coherence & structure | 89.4 | 74.89 |
| Academic style | 80.3 | 69.22 |
| Precision | 84.6 | 67.44 |
| Naturalness | 87.5 | 71.33 |
| Citation integration | 94.2 | 71.11 |
| Semantic fidelity | 91.7 | 73.0 |
Citeproc keys / Formatted citations
Five source texts used structured citeproc keys and five used already formatted references. That prevents format-specific weaknesses from disappearing inside an average.
Formatted citations performed clearly better at 76.75 quality points than citeproc at 64.0. One of the five formatted cases did not return a usable output.
| Metric | Certentis | RewriteAI |
|---|---|---|
| Quality | 85.0 | 64.0 |
| Fidelity | 90.6 | 68.6 |
| Citation integration | 92.8 | 63.6 |
| Citations exact | 3/5 | 1/5 |
| Human + Mixed | 97.4% | 79.98% |
| Word ratio | 0.96 | 1.08 |
| Metric | Certentis | RewriteAI |
|---|---|---|
| Quality | 85.8 | 76.75 |
| Fidelity | 92.8 | 78.5 |
| Citation integration | 95.6 | 80.5 |
| Citations exact | 5/5 | 3/4 |
| Human + Mixed | 88.51% | 76.45% |
| Word ratio | 0.99 | 1.09 |
Observation from the benchmark
These observations come from individual cases in the archived run. They explain the metrics, but they are not blanket claims about every future output.
One formatted Spanish case was rated near source quality, and individual English and Italian outputs were readable and complete.
The Spanish citeproc case contained a statement reversed into its opposite; other cases omitted methodology or citation references.
The tenth case was not silently replaced with another attempt. Aggregate values therefore transparently use nine usable rewrites.
What the numbers mean in practice
The right tool depends on whether you prioritize the highest detector classification, a particular writing style, or a controlled academic rewrite.
Certentis
every result needs to be dependable and meaning, citation, and completeness checks matter more than occasional peak outputs.
RewriteAI
general rewrites will be checked manually and an occasional missing or weaker output is acceptable.
The different case counts are not a rounding issue: RewriteAI did not return one usable result for the ten source texts.
The comparison therefore reports four of nine and nine of nine instead of hiding the failed case.
Even when considering only the nine usable cases, the quality and semantic gaps remained substantial.
Internal benchmark
Every provider received the same source texts. Outputs were scored against a fixed rubric without visible provider labels. Missing results, language drift, and changed citations remained visible.
Ten identical source texts with standard and structured citations
Blinded quality review across eight dimensions
Separate comparison of facts, qualifications, and intended meaning
Additional checks for language, word ratio, and complete citations
The results describe a dated run and do not guarantee every future output.
Provider models, prices, and product versions may change after the test.
Ten cases are a practical product test, not a complete representation of every text type.
Human + Mixed is an external document classification, not a percentage of human-written sentences.
One of ten outputs in the documented run was unusable. The missing case was not silently replaced.
Yes. Certentis combines rewriting with production checks for language, length, and existing citations.
Certentis scored 91.7 in semantic fidelity and RewriteAI scored 73.0.
No. This run is a dated sample of ten demanding multilingual texts. It reveals concrete strengths and risks, but it does not replace testing your own document.
The classification describes how an external scanner categorizes a document. It does not assess factual correctness, citation preservation, language stability, or argument quality.
Every reference present in the source had to remain complete and unchanged in the rewrite. A missing, reformatted, or damaged citation meant the case did not pass as exact.
Compare all seven tools
Every page uses the same benchmark run, so differences can be interpreted without changing the underlying dataset.
Overall quality: 82.4 · Semantic fidelity: 85.4
Read the full comparisonOverall quality: 70.0 · Semantic fidelity: 72.8
Read the full comparisonOverall quality: 42.7 · Semantic fidelity: 62.0
Read the full comparison