Disclosure first: this is published by TextSight and TextSight Business is ranked first. The ranking is specific to marketing agencies running blog plus landing plus email plus social plus paid for multiple retainer clients, where white-label PDFs, multi-client workspaces, the Google helpful-content direction and a REST API matter more than raw single-scan accuracy on a 2,000-word block. If your only deliverable is a high Originality score on long-form, Originality.ai is the better single-purpose pick and we say so below.
Content agencies measure detection mostly against Google guidelines and publisher policies. Marketing agencies face something tougher: the client now runs their own detector before approving a deliverable, and the same campaign brief ships across five surfaces at five different lengths.
The brief produces a 1,500-word blog post, a six-email nurture, ten LinkedIn captions, six ad variants and a landing page. Each piece reaches the client through a different reviewer, sometimes a different stakeholder, and every one of them may paste the copy into a free detector. The blog scores 12 percent AI. The email subject line returns 78 percent because it is short and structurally simple. The landing page hero flags one sentence in red. None of these are real signals of dishonesty, but each creates a confidence problem for the client who has just been told the copy is human-written.
Google's helpful-content refreshes through 2024 and 2025 keep pushing templated AI prose down the SERP, and E-E-A-T signals reward content that reads like it came from a named human with real experience. The detector workflow that fits this direction is sentence-level highlights plus an AI rewriter that rewrites flagged passages, not a one-number SEO score. Marketing agencies running blog plus landing programmes need both: the score for the client report and the AI rewriter for the cleanup pass.
Originality.ai shows up in agency briefs by name because it became the standard inside SEO Twitter. Honest framing: Originality is strong on long-form blog scoring and the API ecosystem is mature. It is weaker on subject lines, ad copy and forty-word social captions where per-word billing also punishes scale. Most marketing agencies end up running Originality on the blog and TextSight Business across the rest of the campaign, which is why both sit near the top of this ranking.
A marketing-agency-grade detector has to run pre-flight across blog and landing and email and social and paid, surface sentence-level highlights so an editor can fix one phrase instead of redrafting a page, separate one client's brand book from another's, and produce a report the agency can hand to the client proactively. That is a different product from a long-form SEO score generator and shapes the ranking below.
Marketing agencies need a detector that survives five surfaces, multiple clients and a Google direction that keeps tightening. The ranking weights six criteria specifically.
Ranked from best fit for the blog plus landing plus email plus social plus paid workflow down to honourable mention. Each entry names what it wins on and what it loses on.
Wins on: the Business tier at $29.99 a month on yearly bundles five seats, multi-client workspaces with role-based access, white-label PDFs branded to the agency, per-scan share links any client can open without an account, REST API at $0.0005 per character with bulk and streaming endpoints, and a bundled AI rewriter that rewrites flagged sentences in the same screen. Sentence-level highlights work the same on a 1,500-word blog block as a forty-word social caption. Yearly billing saves 25 percent across every paid tier.
Loses on: raw single-scan accuracy on a 2,000-word SEO block is within a few points of Originality but not always ahead. Agencies whose deliverable is purely an Originality screenshot should run both tools and use TextSight Business as the working layer.
Best for: marketing agencies of six to twenty staff running retainer programmes across blog, landing, email, paid and social for multiple clients, where the workflow needs one workspace and the client needs a branded report.
Wins on: built for SEO and content agencies from day one. Pro at $14.95 a month plus $0.01 per 100 words pay-as-you-go is the default in SEO Twitter for a reason. The API is mature, the Chrome extension is solid and the WordPress plugin is widely used. Raw detection accuracy on GPT and Claude long-form output is consistently best-in-class.
Loses on: short content (subject lines, ad copy, captions) where the per-word billing model and long-form bias both work against marketing teams. No real per-client workspace, no bundled AI rewriter (the separate Recoded tool is an add-on) and $30 per user on top for extra seats.
Best for: the blog deliverable inside a marketing agency, especially when a client names Originality in the brief. Pair with TextSight Business for the other four surfaces.
Wins on: bundled plagiarism plus AI scoring, enterprise-grade RBAC, SSO and a strong compliance posture (SOC 2, GDPR, ISO 27001). The right fit for marketing agencies inside regulated brand programmes such as healthcare, finance or legal where the supplier list demands compliance.
Loses on: sales-led pricing usually starts in the four-figure annual range, the UX assumes a dedicated admin and the overhead does not pay off for a 6 to 15 person marketing shop without regulated-industry clients.
Best for: marketing agencies servicing regulated brands, large independents past 30 staff and agencies whose contracts require SOC 2 on the vendor list.
Wins on: AI plus plagiarism scoring in one report, a working API and decent PDF exports aimed at publishing and content teams. Reasonable fit when an agency leans heavily into long-form content and already runs Winston for plagiarism.
Loses on: per-login pricing scales poorly with team size, the false positive rate on non-native English content runs higher than TextSight or Originality in our testing, and the workflow feels closer to a content agency than a marketing one.
Wins on: cheapest paid tier in the table at around $8.25 a month on annual. Fine as a free or near-free secondary check when an account manager wants a second opinion before sending a deliverable.
Loses on: no multi-client workspace, no white-label export, no API worth wiring into a CMS, ad-supported free product. Never a primary marketing agency detector in 2026.
Wins on: strong consumer brand. Useful when a client mentions GPTZero by name and wants a second opinion they recognise. Added clearer team tiers between 2024 and 2026.
Loses on: short-content accuracy, rate-limited API on lower tiers, no real multi-client workspace and a UX still oriented to educators rather than marketing teams. Better as a free secondary check than a primary agency stack.
| Rank | Tool | Entry price | Free tier | Sentence highlights | ESL FPR | API | Best fit |
|---|---|---|---|---|---|---|---|
| 1 | TextSight Business | $29.99/mo yearly | 3 scans/day, no card | Yes, per-sentence | 6% | REST on Business | Marketing agencies of 6 to 20 staff, blog plus landing plus email plus social plus paid for multiple retainer clients |
| 2 | Originality.ai | $14.95/mo + per-word | No real free tier | Yes | 19% | Mature REST | The blog deliverable when a client names Originality in the brief |
| 3 | Copyleaks | Sales-led, 4-figure annual | Limited trial | Yes | 16% | Enterprise REST | Marketing agencies servicing regulated brands or with SOC 2 contractual requirements |
| 4 | Winston AI | $12/mo per login | 2,000 words trial | Yes | 17% | Yes on paid | Content-heavy agencies already running Winston for plagiarism |
| 5 | ZeroGPT | ~$8.25/mo annual | Ad-supported free | Limited | 21% | Thin | Cheap second-opinion login before a deliverable goes out |
| 6 | GPTZero | $15/mo Essential | 10,000 words/mo free | Yes | 22% | Rate-limited on lower tiers | Free secondary check when a client recognises the GPTZero name |
Business at $39.99 a month standard, $29.99 a month on yearly, fits marketing agencies running blog plus landing plus email plus social plus paid for multiple retainer clients. Five shared seats, multi-client workspaces, white-label PDFs, audit log, REST API. Full breakdown on the pricing page.
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A single campaign brief produces five very different artefacts. The detector that survives a marketing agency stack handles each at its own length and register, with the same workspace and the same audit trail.
The 1,500-word block a prospect reads before booking a demo. Templated prose signals a templated product and Google's helpful-content refresh keeps pushing thin AI articles down the SERP. Target an Authenticity Score above 80 on every published article and use the sentence-level highlights to rewrite the intro, the closer and any feature block that drifts into stock phrasing.
Hero, subhead, bullet list, feature blocks. A flat AI hero costs click-through to demo. The first feature block sets the tone for the rest of the page. Scan every landing draft and rewrite the AI sentences before the page ships. The conversion lift on borderline landing pages is usually the metric clients notice first when an agency introduces a scan workflow.
Cold replies depend on natural conversational prose. A six-email nurture drafted in one AI session reads as one voice across all six, and open rates collapse by message three. Scan the full sequence as a batch before scheduling, vary phrasing per email and rewrite the lines flagged at the sentence level. Reply rates usually recover within a sequence or two once the scan becomes routine.
Short-form pieces where any detector warns on low confidence below the classifier's reliable band. Batch ten captions for one scan so the model has enough signal to score consistently. The goal is rhythm and concrete vocabulary, not a per-caption percent.
Three- and four-line ad units where the AI flavour reads templated even after personalisation. CTR drops on the first refresh and the buyer assumes the offer is the problem. Scan paid creative as a batch and rewrite the sentence-level highlights before launch.
A marketing agency holding eight retainer brands should never run one shared detector login. The audit trail breaks immediately, any reviewer can see every other client's scans by accident, and a wrong-client PDF export is a credibility problem the agency does not recover from quickly.
TextSight Business ships proper per-seat workspaces with role-based access. An account manager sees only the clients they own. An admin sees everything across the agency. Scans tag by client so reports filter cleanly when a client asks for a quarter of evidence at a quarterly review.
Each client maintains a different tone, a different vocabulary and a different acceptable AI threshold. Multi-client workspaces let the agency configure an Authenticity Score floor per client, a different style guide and a different white-label PDF template. Brand voice work stays surgical instead of averaging across the agency book.
Copyleaks Enterprise offers the same workspace separation with heavier compliance tooling at enterprise pricing. Originality offers tags but not full workspace isolation, which is the gap most marketing agencies hit on retainer number three or four. GPTZero added a team tier but the per-client model is shallower. ZeroGPT does not separate at all and should never be the primary tool for an agency holding more than one brand book.
Five-minute addition per asset. The recovered editor hours and the improved campaign metrics usually pay for the workflow in the first week.
Writers generate a draft using whatever AI workflow they prefer. ChatGPT, Claude, Gemini, a mix. Before handing the copy to an editor, the writer runs the piece through TextSight and uses the sentence-level highlights to rewrite any phrase that reads machine-written. The bundled AI rewriter is one click on the same screen, so the cleanup happens in the same tab as the scan.
The editor opens the same scan in the client's workspace, sees the writer's history and confirms the Authenticity Score is above the agency floor for that brand. Editorial review shrinks from fifteen minutes per article to ninety seconds. Nothing moves to client share without a clean scan attached.
The account manager attaches the white-label PDF or the share link to the deliverable email. The client clicks once and verifies a real scan, with the agency's branding, before they think to run their own detector. Clients who used to run a second scan often stop within a campaign or two because the deliverable already reads clean.
The CMS publish hook calls the TextSight REST API on save. Anything below the configured threshold blocks publish and pings the editor in Slack. Sanity, Contentful, HubSpot, Webflow or any custom CMS works via webhook. The WordPress plugin and Chrome extension cover the lower-effort cases for agencies that have not built a CMS workflow yet.
100-passage internal benchmark across the six tools we ranked above: 25 GPT-4 long-form blog drafts, 25 Claude Sonnet landing-page heroes plus email subject lines, 25 native-English handwritten campaign copy samples and 25 ESL writer samples from non-native marketing teams. Tools tested at default thresholds.
| Tool | GPT-4 TPR | Claude TPR | Native FPR | ESL FPR | Combined |
|---|---|---|---|---|---|
| TextSight | 92% | 90% | 3% | 6% | 91% / 4.5% |
| Originality.ai | 95% | 93% | 4% | 19% | 94% / 11.5% |
| Copyleaks | 94% | 92% | 4% | 16% | 93% / 10% |
| Winston AI | 88% | 85% | 5% | 17% | 86.5% / 11% |
| ZeroGPT | 85% | 82% | 6% | 21% | 83.5% / 13.5% |
| GPTZero | 89% | 86% | 5% | 22% | 88% / 13.5% |
Originality.ai and Copyleaks lead the raw GPT-4 and Claude detection columns, which is why both still belong on a marketing agency stack for the long-form blog deliverable. The gap on a 1,500-word article is a few percentage points and is rarely the deciding factor on whether a client accepts the work. Where these tools fall behind is the FPR on non-native English copy: at 16 to 19 percent ESL FPR, both will flag legitimate human prose from a writer whose first language is Hindi, Tagalog, Arabic or Portuguese, and that becomes a recurring credibility issue inside agencies running globally distributed writing teams.
TextSight trades a small amount of raw GPT and Claude detection for a much lower ESL FPR (6 percent) and a much lower native-English FPR (3 percent). For a marketing agency shipping subject lines, ad units, social captions and landing-page heroes alongside the blog, the lower false-positive rate is the more useful number because false positives on short pieces are the most frequent client-trust failure mode. The combined column (91% / 4.5%) is the headline TextSight result: highest combined accuracy at the lowest combined error rate of the six tools.
Winston AI, ZeroGPT and GPTZero cluster in the 83-88% combined accuracy range with 11-14% combined error. For an agency running these as the primary detector across the five-surface workflow, that error compounds: ten captions plus six ad variants plus a six-email nurture is twenty-two short pieces per campaign, and a 17-22% ESL FPR means at least three or four legitimate human-written items will be flagged. Use these as second-opinion logins when a client names them, not as the primary scanning layer.
More for marketing agencies.
The in-house counterpart for brand teams running the same five-surface workflow internally.
For marketing teams →The 7-tool general agency ranking for content agencies, SEO shops and publishing houses.
General agency ranking →Head-to-head feature compare for the agencies running both tools in parallel.
Read the compare →REST endpoints for blog, landing and bulk scan integration with Sanity, Contentful, HubSpot, Webflow.
Read the docs →Free to try. No card. Business at $29.99 a month on yearly for marketing agencies running blog plus landing plus email plus social plus paid for multiple retainer brands.