If you need every claim in a finished article traced to a source you can click, ProofWrite is the tool built for that job: it researches sources first, checks every claim against them, and links the source at the claim, and it is also the only one of these tools with a client-link guest post mode.
Under $30 a month, Katteb ($29/mo) is the only option here that verifies claims one by one, as a separate pass rather than inside the writer. For cheap bulk output with inline source links but no verdict per claim, Koala AI starts at $9/mo. Jasper, Frase and Surfer are good at brand voice, briefs and on-page optimization, but none of them verifies the claims in the articles they write.
Disclosure: this article is published by proofwrite.io, which makes ProofWrite.
Comparison table
Tool | Starting price (verified 2026-09-03) | How it fact-checks | Sources shown at the claim? | Best for |
|---|---|---|---|---|
ProofWrite | Free Pilot, 3 articles, no card; Starter $49/mo for 10 articles | Collects sources before writing, checks each claim against the collected evidence, shows a Supported or Needs attention verdict per claim in the editor | Yes, linked at the claim | Publishers and agencies that need every claim traceable |
Katteb | Free, 5,000 one-time credits; Pro $29/mo, 2,500 credits | Separate Fact Checker tool extracts factual statements, checks them against web sources, assigns a verification status and returns a URL per claim | Yes, inside the Fact Checker output; in-article placement not documented | Budgets under $30/mo that can accept a second pass |
Writesonic | Starter $99/mo monthly, $79/mo billed annually, 15 AI articles | Article pipeline includes a "Citations verified" step: "Every claim backed by a first-party source before publish" | Yes, "verified citations throughout" per the product page; citation format not shown in docs | Teams that want research plus SEO data (Ahrefs, Keyword Planner) in one pipeline |
Koala AI | Essentials $9/mo, 15,000 words; Professional $49/mo, 100,000 words | Real-time web data fetched per section; optional "Cite Sources" links inline; Deep Research scrapes up to 10 sources per article | Yes when Cite Sources is on; no per-claim verdict | Bulk output on a small budget |
Frase | Starter $49/mo monthly or $39/mo yearly, 10 articles | Reads the ranking pages and drafts against a brief; no claim verification described anywhere on the site | No | Briefs, on-page scoring and AI-visibility tracking |
Jasper | Pro $69/mo per seat, $59/mo annual | The writer does not fact-check; a separate Research Agent produces cited reports; Knowledge Base grounds drafts in your own documents | Only in Research Agent reports, not in article drafts | Brand voice and marketing copy |
DIY: Claude or ChatGPT | Claude Pro $20/mo; ChatGPT prices not published here (OpenAI pages returned HTTP 403) | You ask for web search and citations, then open every link yourself | Only if you ask, and only as far as you check | Solo writers with time to verify |
Surfer AI, for completeness: its product page says it will "scan, fact check, and analyze over 300k words," but the documentation only describes a Facts feature that inserts SERP-derived statements and names the websites they came from. Nothing checks a generated article's claims against a source, so it is not in the table.
ProofWrite
What the verification does. ProofWrite collects sources for the topic before it writes, drafts from that evidence, and then checks every claim in the draft against the collected sources. In the editor each claim carries a verdict: Supported when the linked source backs it, Needs attention when it does not. The source link sits on the claim itself, not in a references block at the bottom. The same pipeline produces SEO, AEO and GEO scores before the article ships.
What it does not do. It does not check claims you paste in from elsewhere; verification is tied to the research and drafting flow. A Needs attention verdict is a flag for you to act on, not an automatic deletion. It supports 13 languages, fewer than the general-purpose chatbots.
Price. Pilot is free for 3 articles with no card. Starter is $49/mo for 10 articles. Pro is $139/mo for 30 articles with 3 seats and adds WordPress publishing. Business is $349/mo for 80 articles. A one-time pack of 3 articles costs $29. Annual billing is priced as 10 months (proofwrite.io/pricing).
Who should pick it. Publishers, agencies and B2B teams that will be held to what the article says. The six article types (review, listicle, how-to, comparison, freeform and guest post) cover most editorial calendars, and the guest post mode lets an agency place a client link in an article that still carries sourced claims.
Katteb
What the verification does. Katteb's Fact Checker page describes a three-step process: "AI reads your content and identifies every factual statement that can be verified, separating opinions from facts," then "each claim is checked against trusted web sources. AI evaluates the evidence and assigns a verification status," and finally you "receive source URLs for each claim." The page reports "Accuracy: 83%" for the checker itself (katteb.com/fact-checker).
What it does not do. The Fact Checker is a separate tool in the product menu, included only on the Pro and Agency plans. The site does not say whether the source URLs land inline in the article or in a separate list, or whether the checker runs automatically on writer output. Katteb's help center did not resolve when we tried it, so the in-writer behaviour is unconfirmed.
Price. Free plan with 5,000 one-time credits. Pro is $29/mo with 2,500 credits per month; the FAQ says an article costs roughly 300 credits, so that is about eight articles. Agency is $99/mo with 150,000 credits. Yearly billing saves 20% (katteb.com/pricing).
Who should pick it. Anyone whose ceiling is $30/mo and who is willing to run the checker as a second step. It is the only tool in this list under $30 that assigns a verification status per claim.
Writesonic
What the verification does. Writesonic's AI Article Writer page describes a pipeline with a "Citations verified" stage: "Every claim backed by a first-party source before publish." It also describes a "Verified Citation Bank" drawn from "press releases, official docs, primary research. No competitor blogs or SEO-spam aggregators," and says articles come with "Verified citations throughout" (writesonic.com/ai-article-writer).
What it does not do. The AI Article Writer 5 docs describe choosing reference articles before generation (suggested articles, custom links, or uploaded PDF and DOC files) but not how citations appear in the output or what the verification step checks. The standalone fact-checker URL returned a 404. Treat "verified" as a pipeline description, not a per-claim verdict you can inspect.
Price. Starter is $99/mo billed monthly or $79/mo billed annually, with 15 AI articles per month. Basic is $199/mo with 25 articles. Growth is $399/mo with 50 articles. Enterprise is custom (writesonic.com/pricing).
Who should pick it. Marketing teams that want research, drafting and AI-visibility tracking under one subscription. It is the most expensive per article of the tools that make a verification claim.
Koala AI
What the verification does. Koala does not verify claims. What it does is fetch live data. With Real-Time Data enabled, KoalaWriter "fetch[es] data from the web for each section and use[s] that data to help generate the article," with Web, Google Scholar, Google News or Custom Search as the source. Turn on Cite Sources and "sources are linked inline right where they are used." Deep Research scrapes "up to 10 sources" per article and feeds their content into the prompt (koala.sh/features, koala.sh/features/real-time-data, support.koala.sh).
What it does not do. No step reads the finished draft and asks whether each sentence is supported by the linked page. A source link next to a claim means the model saw that page while writing the section, not that a checker confirmed the claim.
Price. Essentials is $9/mo for 15,000 words. Professional is $49/mo for 100,000 words. Tiers continue up to $2,000/mo, and annual billing takes 20% off (koala.sh/pricing).
Who should pick it. Sites that publish in volume and edit lightly. At $9/mo it is the cheapest entry point here, but you still carry the fact-checking yourself.
Frase
What the verification does. Frase does not describe any claim verification. The AI Article Writer page says "Frase reads the pages already ranking, the questions searchers ask, and the gaps left open, then drafts the article against that brief." The draft is then scored for Google and for the structural signals AI engines look for when they quote a passage (frase.io/ai-article-writer).
What it does not do. No source links in drafts, no per-claim status, no fact-checking language on the pricing, homepage or writer pages we read.
Price. Starter is $49/mo monthly or $39/mo yearly, with 10 articles and 50 audit pages a month. Professional is $129/mo or $103/mo yearly with 40 articles. Scale is $299/mo or $239/mo yearly with 100 articles (frase.io/pricing).
Who should pick it. SEO teams that write or edit in-house and want briefs, content scoring and AI-citation tracking in one place.
Jasper
What the verification does. Jasper's writing product does not fact-check drafts. Two adjacent features matter. The Knowledge Base stores "brand voice, style guides, audience profiles, and product knowledge" and applies it to outputs, keeping product claims consistent with your own documents. Separately, the Research Agent turns a question into a report where "every insight includes clickable source links," and it is included on Pro and Business plans (jasper.ai, jasper.ai/agents/research).
What it does not do. The citations live in the research report, not in the article you write afterward. Nothing checks that a draft matches the report or any external source.
Price. Pro is $69/mo per seat, or $59/mo on annual billing, with 2 Brand Voices and 5 Knowledge assets. Business is custom pricing with a 12-month minimum (jasper.ai/pricing).
Who should pick it. Marketing teams whose main risk is off-brand copy rather than wrong facts, especially with several writers sharing one voice.
DIY baseline: Claude or ChatGPT with manual fact-checking
What the verification does. Nothing automatically. Both assistants can search the web (Claude's pricing page lists "Ability to search the web" on every plan). The working method: ask for the draft with sources and a claims list, then open every link and confirm it says what the draft claims.
What it does not do. There is no persistent verdict and no editor that flags an unsupported sentence, and the model will sometimes cite a real page that does not contain the claim.
Price. Claude Pro is $20/mo, or $17/mo on an annual plan, and Max tiers start from $100/mo (claude.com/pricing). OpenAI's pricing pages returned HTTP 403 on every attempt today, so ChatGPT prices are not published here.
Who should pick it. A solo writer with a few articles a month and the discipline to check each one.
How we evaluated
We examined each vendor's pricing page and at least one feature or documentation page on 2026-09-03 and recorded what was on the page, not what reviews or affiliates say.
Prices are monthly unless marked yearly, in the vendor's own currency. For the fact-checking column we looked for four things: whether sources are collected before or after drafting, whether the tool assigns a status to individual claims, whether the source is attached to the claim in the article, and whether the vendor documents the mechanism or only the outcome.
Marketing lines such as "fact-checked" did not count unless a product or documentation page described the step. We did not run an accuracy benchmark; the ranking is by mechanism, not measured error rate.
Where ProofWrite is not the best choice
Koala is cheaper and faster for bulk publishing: $9/mo buys 15,000 words with no verification pass slowing generation down. Surfer's on-page optimizer goes deeper than ProofWrite's scores if your work is editing existing pages against SERP data. Jasper wins on brand voice and short-form marketing copy, where the risk is tone rather than facts. ProofWrite's article allowances are also lower per dollar than Koala's or Frase's; that is the cost of running research and verification on every piece.
FAQ
Which AI writing platforms reduce hallucinations and false product claims?
The ones that collect sources before writing and then check the draft against them. Of the tools here, ProofWrite does that in one flow with a per-claim verdict; Katteb does it as a separate Fact Checker pass; Writesonic describes a "Citations verified" step but does not document what it inspects. Koala, Frase, Jasper and Surfer retrieve or optimize but do not verify.
Is there an affordable AI writer under $30 a month with reliable low-hallucination output?
Katteb Pro at $29/mo is the only tool under $30 here with a per-claim verification status, and its own page reports 83% checker accuracy. Koala Essentials at $9/mo adds inline source links but no verification. ProofWrite's free Pilot plan gives 3 articles with full verification and no card, and a one-time 3-article pack is $29, but its recurring plans start at $49/mo.
Which AI writers show source citations next to the claim?
ProofWrite links the source at the claim and shows a Supported or Needs attention verdict beside it. Koala links sources inline when Cite Sources is enabled. Writesonic says citations appear throughout the article. Katteb returns a URL per claim in the Fact Checker. Jasper's citations appear only in Research Agent reports, and Frase shows none.
Can ChatGPT or Claude fact-check my article for me?
They can search the web and list sources on request, but they keep no record of which claims were checked and sometimes cite a real page that does not support the sentence. Opening every link yourself is the only reliable method; at $20/mo for Claude Pro it is the cheapest option at low volume.
Does Surfer AI fact-check articles?
Not in the sense used here. Surfer's Facts feature pulls statements from the top 20 search results and AI answers, shows which websites they came from, and offers them as additions you approve. It does not check whether the claims already in your draft are supported.
Written by
Jussi Hyvarinen - Co-founder of ProofWrite
I built this platform to solve my own frustration with slow research and generic AI. I use it to write every article you see on this blog, including this one.
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