ZeroGPT is the detector most SEO writers reach for first. Free, no daily cap, 15,000 characters per scan, ad-supported result page. That low-friction free flow is a real strength for rapid drafting checks. TextSight came at the same job from a different direction: smaller free tier of 3 scans a day, sentence-level highlights on free, perplexity and burstiness signals, Plagiarism Risk in every scan, an ESL-aware classifier, calibration that aligns with Originality.ai (the detector most clients already run), and a REST API on Business for pre-publish CMS hooks. This is the honest comparison for SEO content workflows. Free to try, no card.
Both ZeroGPT and TextSight scan a draft and return an AI probability. The right way to choose is to look at what a real publish-thirty-posts-a-week SEO workflow actually demands.
SEO writing is the most exposed corner of the content market to AI detection review because every page is built to rank, every client runs their own QA detector, and Google has spent two years tightening the screws on what it calls scaled content abuse. The realistic 2026 workflow uses AI assistance for outline and research, writes the prose with a human pass, and pre-scans the output against the same detector the client uses before publication.
An SEO writer running iterative drafting cycles needs many quick checks across a week. ZeroGPT wins this round on raw volume. The free tier has no hard daily scan cap and accepts up to around 15,000 characters per scan with no email required. TextSight free is 3 scans a day at 5,000 characters per scan but every scan returns sentence-level highlights and Plagiarism Risk. For drafting volume on a budget, ZeroGPT is the friction-free flow.
A document-level score is not a fix path. You see the score is 62 but you do not know which paragraphs are pulling it down or which sentences would trigger Google's scaled-content-abuse signal. ZeroGPT free shows a single colour band and reserves per-sentence breakdowns for Premium. TextSight free returns full sentence-level highlights with a confidence indicator on each one, plus perplexity and burstiness signals on Pro, so you know exactly which lines to rewrite.
Most SEO writers serving clients hit Originality.ai as the client-side QA detector. ZeroGPT scores diverge from Originality.ai on borderline drafts, which means a ZeroGPT-clean piece can still come back from the client flagged. TextSight is explicitly calibrated to score similarly to Originality.ai on long-form content, so pre-scanning before delivery puts you on the same page as the client without locking you into a paid-only tool.
Agency teams shipping fifty or more articles a month or running programmatic SEO templates across hundreds of pages need a REST API hook in the publish step, not a manual paste-by-paste flow. ZeroGPT offers an API at a separate tier with limited structured fields. TextSight on Business returns Authenticity Score, sentence-level results, perplexity, and burstiness as JSON, which is what plugs cleanly into a CMS pre-publish hook or a Notion-to-WordPress automation.
The honest spec sheet for SEO writers. Where each one wins, in one scrollable table.
| Feature | TextSight | ZeroGPT |
|---|---|---|
| Primary product | AI detection plus Authenticity Score plus AI rewriter plus Plagiarism Risk | AI detection, free unlimited ad-supported flow |
| Detection type | DeBERTa plus ELECTRA dual-model, perplexity and burstiness signals, ESL-calibrated | Proprietary classifier, document-level score, no published methodology |
| Free tier | 3 scans per day, 5,000 chars per scan, sentence-level highlights, no ads | Unlimited scans ad-supported, around 15,000 chars per scan, no sentence-level |
| Pricing model | Monthly or yearly (25 percent off), 4 tiers Free, Starter, Pro, Business | Monthly Premium, no native team or agency tier |
| Entry price | Starter $9.99 per month ($7.49 yearly effective) | Premium around $9.99 per month flat |
| Pro annual effective | $14.99 per month, billed $179.88 yearly | No yearly discount published |
| .edu discount | Pro $13.99 per month yearly for verified .edu | No published .edu discount |
| Sentence-level evidence | Yes on free, with per-sentence confidence indicator | Premium only, single colour band on flagged sentences |
| ESL FPR | 6 percent (internal 100-passage benchmark) | 21 percent (independent ESL benchmark) |
| Native FPR | 3 percent | 6 percent |
| GPT-4 TPR | 92 percent | 85 percent |
| Claude TPR | 90 percent | 82 percent |
| Bundled AI rewriter | Yes, integrated, up to 100,000 words per month on Business | Sold as a separate ZeroGPT product, not bundled with detector |
| REST API | Yes on Business, full JSON with sentence-level results, perplexity, burstiness | Separate paid API tier, limited structured fields, no per-sentence response |
| Best fit | SEO writers and agencies who need Originality.ai-aware scoring, sentence-level evidence, REST API hooks, and audit-log reporting | Casual bloggers and writers who want unlimited fast drafting checks and accept ads and Premium-gated evidence |
Numbers reflect published 2026 pricing pages and our internal benchmarks on long-form SEO content. Verify on the vendor pricing page before committing to a paid plan.
Yearly billing saves 25 percent. Pro fits solo writers shipping ten to thirty pieces a month. Business fits agencies and in-house SEO teams running CMS pipelines. Full details on the pricing page.
Billed $89.88/year — Save $30
Billed $179.88/year — Save $60
Billed $359.88/year — Save $120
For comparison, ZeroGPT Premium is around $9.99 a month with no team plan, no bundled AI rewriter, and no REST API at parity. View full pricing →
Honest call-outs. These are real reasons many SEO writers start with ZeroGPT and keep it in the toolkit for fast drafting checks.
This is the headline. ZeroGPT free has no hard daily cap on detection scans for most users. If your drafting workflow is paste, score, edit, repaste, repeat across thirty articles a week, ZeroGPT is the only tool in the category that does not throw a paywall at scan four. For SEO writers running iterative cycles during a long drafting day, the unlimited free flow is genuinely useful and worth stating up front.
The ZeroGPT homepage accepts a paragraph and returns a score in one click. No email, no card, no account creation. For a writer onboarding a new client who wants a quick check on the brief, ZeroGPT will return a gut-check faster than any tool that asks you to sign up first. That zero-friction onboarding is a real strength.
ZeroGPT free accepts around 15,000 characters per scan. TextSight free is 5,000 characters per scan. If you want to paste an entire 2,500-word pillar draft in one shot rather than splitting it into chunks, ZeroGPT is the tool that lets you do that without paying. For long-form pillar content checked as a single block, the character ceiling matters.
ZeroGPT has heavy organic traffic and broad brand recognition. When a client says "run it through ZeroGPT before delivery" it is sometimes the literal tool they mean, not a generic ask. Keeping ZeroGPT in the toolkit for those specific client conversations is operationally smart even when TextSight is the daily driver for actual quality work.
ZeroGPT Premium is around $9.99 a month flat. If your only reason to upgrade is ad removal and faster scans during drafting, that price is hard to beat. TextSight Pro at $14.99 a month yearly costs more, but it bundles things ZeroGPT sells separately, so the comparison only works on a feature-by-feature read.
Six specific reasons SEO writers migrate from ZeroGPT to TextSight, or run TextSight as the final pre-publish and pre-delivery scan.
When TextSight flags a 1,500-word draft at 62, the colour map shows you exactly which sentences scored worst with a confidence indicator on each one. You see the evidence behind the score, not just the score itself. On a 30-post workflow, that is the difference between rewriting the whole piece defensively and editing the four to seven sentences that are actually reading red. ZeroGPT free shows a single colour band and reserves the per-sentence breakdown for Premium.
Most SEO clients running their own QA detector use Originality.ai. TextSight is calibrated to score similarly to Originality.ai on long-form content, which means a TextSight-clean draft tends to come back Originality-clean too. ZeroGPT is not calibrated against Originality.ai and the scores can diverge significantly on borderline drafts, so a ZeroGPT-clean piece can still get bounced back from the client. Pre-scanning with TextSight before delivery puts you on the same page as the client.
ZeroGPT funds the free flow through display ads and upsell modals on the result page. TextSight is ad-free on every page including the result view. For SEO writers doing serious paragraph-level editing at the end of a long day, the signal-to-noise ratio on the result page matters. The absence of ad clutter is worth more than the marginal scan-volume difference once you are past the drafting phase.
TextSight on Business returns Authenticity Score, sentence-level results, perplexity, and burstiness as JSON through a REST API. Most agency teams plug it into a pre-publish hook in their CMS or in a Notion-to-WordPress automation, so every article gets scanned before it goes live and any piece below the agency floor flags for editor review automatically. ZeroGPT offers an API at a separate tier but does not return sentence-level highlights or perplexity and burstiness as structured fields, which is what the pipeline integration actually needs.
Content agencies routinely staff writers across timezones, including writers working in non-native English registers. ZeroGPT is trained on broad web data and does not advertise ESL calibration, which means it over-flags non-native English drafts. TextSight is explicitly tuned against ESL writing samples and produces meaningfully fewer false positives on non-native registers. For agencies that staff globally, that calibration prevents the conversation where a writer is asked to "rewrite to sound less AI" when the actual problem is the detector mis-reading the register.
On Business, TextSight provides an audit log showing which writer scanned which deliverable with timestamps, and white-label PDFs branded to your agency for monthly client reporting. The /accuracy page publishes the detection methodology and benchmark data. ZeroGPT publishes none of that. For agencies that need to demonstrate consistent AI-quality control across a writing team and produce client-facing scan reports, the audit and reporting infrastructure on Business is what makes the workflow defensible.
Internal benchmark on 100 long-form passages per detector. 50 AI (25 GPT-4, 25 Claude), 50 human (25 native English, 25 ESL). Last verified 2026-06-03.
| Detector | GPT-4 TPR | Claude TPR | Native FPR | ESL FPR | Combined |
|---|---|---|---|---|---|
| TextSight | 92% | 90% | 3% | 6% | 91% / 4.5% |
| ZeroGPT | 85% | 82% | 6% | 21% | 83.5% / 13.5% |
| Originality.ai | 95% | 93% | 4% | 19% | 94% / 11.5% |
| GPTZero | 89% | 86% | 5% | 22% | 88% / 13.5% |
| Copyleaks | 94% | 92% | 4% | 16% | 93% / 10% |
Google's March 2024 core update and the March 2025 helpful-content refresh penalise what they call scaled content abuse. SEO writers cannot afford an 88 to 94 percent TPR detector returning clean on a draft that Google's helpful-content classifier will flag. TextSight's 91 percent combined TPR on long-form is calibrated specifically against the kind of GPT-4 and Claude drafting that fills agency briefs in 2026. ZeroGPT's 83.5 percent combined is materially lower, which on a pillar piece means roughly one in six AI-heavy paragraphs reads clean to ZeroGPT but red to Google. For pre-publish SERP-safety, the detector you scan with should be at least as strict as the classifier you are protecting against, not looser.
For SEO writers serving multiple clients, the dominant client-side QA detector is Originality.ai. The benchmark above puts TextSight's combined score within 3 percentage points of Originality.ai (91 percent vs 94 percent TPR) with a substantially lower 6 percent ESL FPR versus 19 percent. In practice that means a TextSight-clean draft tends to come back Originality-clean too, so a writer can pre-scan with TextSight and ship without the round-trip of client-side rejection. ZeroGPT sits 10 to 11 percentage points behind on combined TPR and 15 points worse on ESL FPR, so a ZeroGPT-clean draft is far more likely to bounce back from the client. For portfolio quality across ten plus clients, alignment with the client's actual detector is the single most operationally valuable signal.
The 15 point ESL-FPR gap (TextSight 6 percent, ZeroGPT 21 percent) compounds for agencies that staff writers globally and for any team running programmatic SEO at scale. On a 200-page programmatic cluster scanned by ZeroGPT, the expected false-positive count on the ESL-staffed pages is roughly 3.5 times higher than with TextSight. Each false positive triggers a defensive rewrite, an editor escalation, or a client conversation that does not need to happen. At Business pricing of $29.99 yearly, the REST API hook into the publish step plus the lower FPR pays for itself inside the first month for any team shipping 50 or more articles. ZeroGPT Premium at $9.99 reads cheaper on sticker but does not include team seats, REST API at parity, audit log, or white-label PDFs.
A quick decision matrix for the most common SEO content workflows. If your situation is mixed, run both, in the order shown.
Pick TextSight Pro at $14.99 yearly. Unlimited scans, sentence highlights, Originality-aware calibration, integrated AI rewriter. Use ZeroGPT free as the bulk drafting flow.
Get Pro →Pick TextSight Business at $29.99 yearly. REST API for CMS hooks, 5 seats, audit log, white-label PDFs. Use ZeroGPT free as a secondary drafting check only.
Get Business →Pick TextSight Business for the REST API. Scan a sample per template, rewrite the scaffolding, then hook the API into the publish step so every page gets pre-scanned automatically.
Get Business →Use ZeroGPT free for unlimited rough drafting checks. Run TextSight free once before publish for the sentence-level evidence and Plagiarism Risk that catches what ZeroGPT misses.
Start free →If you can only pick one, here is the call. If you can run both, here is the order.
Pick TextSight as primary: sentence-level evidence on free, calibration that aligns with Originality.ai (the detector most clients run), ESL-aware classifier, perplexity and burstiness signals on Pro, REST API on Business for CMS pre-publish hooks, audit log and white-label PDFs for agency client reporting, Plagiarism Risk bundled in every scan, no ads. Best daily driver for SEO writers who need the evidence behind the score and need scores that match what the client's QA detector will say.
Use ZeroGPT as the high-volume drafting flow: free unlimited scanning, no signup, higher per-scan character ceiling, faster onboarding. Real strengths if your drafting workflow involves many iterative scans in a single session and you do not need sentence-level evidence on free. Run it during drafting, then run TextSight once before publish and once before delivery as the deciding signal.
One-line answer: for any SEO writer serving clients who run Originality.ai, TextSight first because the scores align. For solo writers on a budget running heavy drafting cycles, ZeroGPT free during drafting and TextSight free or Pro for the pre-publish scan. For agencies and programmatic SEO operations at scale, TextSight Business is not optional because the REST API is the only realistic way to scan hundreds of pages per template at the publish step.
All-audience deep comparison, with feature parity matrix and the cross-check workflow.
See the full vs page →The SEO writer hub: E-E-A-T context, AI Overview citation, programmatic SEO defence, REST API workflow.
See the hub →The detector most SEO clients run for QA. Side-by-side feature, pricing, and calibration comparison.
Read the comparison →The agency workflow: REST API, white-label PDFs, audit log, and the quarterly cluster audit ritual.
See the agency hub →Free to try. No card. Sentence-level evidence, Originality.ai-aware calibration, and a REST API on Business when your workflow needs the publish-step hook.