Best online diff checkers for text, code, and PDFs

An online diff checker takes two versions of a text and marks what was added, removed, or changed. All five tools compared here do that basic job, so it is not what separates them. What does is where your text is processed and which file types the tool can open, with price settling the rest.

What to weigh before choosing an online diff checker

Each vendor page describes its own tool, so lining them up is left to you. Three questions sort these tools faster than any feature count, and each one has a short answer on the vendor's own page. Settle them in this order and the shortlist usually drops to one or two names.

Where your text goes: browser-only vs. server upload

A browser-only checker runs the comparison in JavaScript on your own computer, so neither version travels anywhere. A server-based checker posts both versions to the vendor, compares them there, and sends back the result. Encryption protects the text on the way, but the text has still left your machine.

That difference matters for contracts, personnel files, unreleased source code, and anything your employer's data policy covers. Of the five tools here, sakuttoAI and CodeSamplez work in the browser, and Diffchecker says the same of text comparisons on its website. Text Compare is the one that processes your text on its server.

Character-level vs. line-level diff granularity

A line-level diff flags the whole line when a single comma moves. With short lines of code that is enough, but in a long paragraph you end up rereading two near-identical blocks to find one edit. A character-level or word-level diff goes further and highlights the exact span that changed inside the line.

For prose, contracts, and translation checks, pick a tool that works at least at word level. sakuttoAI marks individual characters, and CodeSamplez marks words inside each changed line. Diffchecker's free plan gives word-level results without a cap but rations character-level ones.

File types: plain text and code vs. PDF, Word, and Excel

Plain text and source code can go into any of these five tools by pasting. Office files are a different job, because the tool has to pull the text out first. A scanned PDF also needs OCR (optical character recognition) before there is any text to compare.

Among these five tools, only Diffchecker and Draftable read PDF, Word, and Excel files directly. sakuttoAI and Text Compare take pasted text only. CodeSamplez also accepts a text file you drop onto the page and reads it inside the browser.

Online diff checkers compared at a glance

The two tables below cover the same five tools from different angles, with prices as listed on each vendor's page in September 2026. The first answers where your text goes and what the tool costs. The second answers what you can feed it.

Processing location and lowest price by tool

Input types each tool accepts

Reading the feature and price columns

"Free, capped" means Diffchecker's Basic plan costs nothing but limits several features to 5 or 10 uses a month. Draftable's $129 is the Business plan per user per year, sold only on annual billing. Every other tool in “Processing location and lowest price by tool” is free with no account and no stated monthly limit.

"Runs in" is the column to read first if the text is confidential. Diffchecker's row covers text pasted into its website. For office files, its pricing page ties the promise that files stay on your device to the desktop app, which starts with the $15 Pro + Desktop plan.

sakuttoAI for character-level text and code diffs

sakuttoAI is the diff tool on this site, and the facts below come from its source code rather than a marketing page. It suits everyday text and code where you want to see the exact characters that changed and nothing leaves your browser.

Processing model and privacy

The comparison runs in your browser. The tool code makes no network request with your text, and there is no upload step, because you paste both versions into two panels. That also means there is no file picker, so a Word or PDF file has to be copied out as text first.

Under the hood it uses jsdiff, the open-source npm "diff" library that CodeSamplez also builds on. Lines that changed are paired up and compared again character by character. That second pass is why a moved comma shows as one highlighted mark instead of a whole red line.

Diff view and merge features

You can switch between a side-by-side view and a unified (inline) view at any time. Side-by-side is easier when the two versions differ a lot. Unified reads better on a narrow screen or when the edits are small and scattered.

The merge controls let you keep or discard each change one at a time. A navigation bar lets you jump between changes, so a long document does not need scrolling to find the next edit. For combining two drafts into one clean file, the Compare Two Documents to Check Proofreading Edits guide walks through the full flow.

Price and account requirements

sakuttoAI is free and needs no account. There is no monthly cap on comparisons, and no paid tier sits behind the merge or character-level features. The trade-off is scope, since the tool does not read PDFs or spreadsheets.

Diffchecker for feature-complete free and paid diffing

Diffchecker's name has become a search term of its own: "diffchecker online" ties for the most-searched query in the whole diff checker family. Its free web app covers text, documents, images, and spreadsheets, while the paid plans remove monthly limits and add a desktop app.

What the free Basic plan actually limits

Basic is free for good and includes the side-by-side view and word-level results with no cap. Several features are rationed per month, and the pricing table counts each one separately:

• Unified view, syntax highlighting, hiding whitespace changes, and PDF export: 5 tries each
• Character-level differences and merging changes: 10 tries each
• Excel formula-change detection: 10 tries
• AI summaries of the changes: 5 for a whole diff and 20 for single blocks

Document and spreadsheet comparison itself is not capped. Basic reads DOC, DOCX, PDF, PPTX, XLSX, XLS, CSV, and TSV, and it can compare scanned PDFs with OCR. Ads are shown on Basic, and no plan has a file size limit.

Pro, Legal, and Enterprise plans compared

Pro + Desktop removes every monthly cap and adds the desktop app. Legal is the same bundle plus iManage integration and saved comparison profiles, which matters mainly to law firms. Enterprise adds SAML single sign-on and dedicated support, and it is sold on annual billing only.

Subscriptions renew monthly or yearly depending on the plan you pick. The feature table splits the $15 bundle into separate Pro and Desktop columns, and it marks redline output for documents, as well as folder and batch comparison, only under Desktop, Legal, and Enterprise.

Desktop app and offline access

The desktop app runs on Windows, macOS, and Linux. The pricing table lists two things only for the desktop plans: files that never leave your device, and fully offline use. Plain text already compares in the browser on the website, so the desktop app earns its price mainly on office files and on work without a connection.

The desktop plan gives up cloud save and share links, which the web plans keep. One license covers three devices at once if you are the main user of each. As of September 2026, Diffchecker is the only tool of the five with a desktop app for Mac.

Text Compare for simple, sign-up-free text diffing

Text Compare is the quick option for someone who wants to paste two versions and see the edits in seconds. It is free and works from any device with a browser. Its biggest limit shows up when the text is sensitive.

How the server-side comparison works

You paste the old and new versions into two fields and run the comparison. The page then marks additions, deletions, and modifications. The page does not say whether it marks changes by character, word, or line, so try it on a long paragraph before you rely on it.

The comparison itself happens on Text Compare's server. The text travels there over an encrypted connection, and the site says it is not stored. The page also has small cleanup buttons, such as lowercasing and sorting lines, which help when you only care about content changes.

Where it falls short for confidential text

"Not stored" is a promise about what happens after the comparison, not a guarantee that the text never leaves your computer. For a contract draft or anything covered by a confidentiality clause, that gap can be enough to rule the tool out. The vendor says as much and suggests an offline tool for sensitive material.

The page also offers no file upload, no merge feature, and no document formats. For short everyday snippets it is hard to beat, but a browser-only tool covers the same use without the upload.

CodeSamplez Diff Checker for 100% client-side code diffs

CodeSamplez is a free developer tool that runs the whole comparison in the browser. It fits the code and markup side of diff checking, where you compare source files, config files, or exported data rather than prose.

Supported languages and file formats

It accepts plain text and code in languages such as Python, JavaScript, Java, and C++. It also names JSON, XML, HTML, and CSS, which covers most "xml diff checker" and "html diff checker" searches. SQL is not on the list, yet it is plain text, so a SQL diff works the same way.

When it detects code, results come back with syntax highlighting. Each changed line shows word-level differences. Whitespace is ignored by default, which hides indentation noise; switch that option off when a tab or trailing space is the point.

Offline use and upload limits

Once the page has loaded, you can disconnect and keep comparing, because nothing depends on a server. You can drop a local text file onto either pane, and the browser reads it without uploading it. The current comparison can also be saved as a standard .patch file.

There is no fixed size limit. Very large inputs can slow down, since your own browser does all the work, and the tool suggests splitting huge files or using a desktop diff tool. Price is not a factor: it is free, needs no registration, and places no limit on the number of comparisons.

Draftable for scanned PDF, Word, and Excel document diffs

Draftable Compare is a paid desktop tool built for reviewing documents rather than pasted text. It reads Word, PDF, PowerPoint, and Excel, and it handles scanned PDFs as well. It is the tool of the five aimed at people who redline documents for a living.

Business and Legal plan pricing

Both prices assume annual billing, and a subscription runs for the full 12 months once activated. Business shows changes as highlights in a side-by-side view. Legal adds redlines for Word, PDF, Excel, PowerPoint, and Outlook emails, plus integrations with Microsoft Office, iManage, NetDocuments, and SharePoint.

You can try either plan free for 5 days, with no usage limits during the trial. After that, neither plan caps the number of comparisons, which is the main contrast with Diffchecker's free tier.

Mac availability and deployment options

Both plans install as a Windows desktop application. Mac support is listed as coming late in 2026, so as of September 2026 a Mac user cannot run Draftable's desktop app. If you searched for a diff checker for Mac, Diffchecker's desktop app or a browser-based tool is the answer for now.

For organizations, Draftable also offers a hosted API, a self-hosted API, and an online option. It lists ISO 27001:2022 certification along with SOC 2 and GDPR compliance, which helps when an IT team has to sign off before rollout.

Match the checker to your file type, budget, and privacy needs

Start with where the text may go, then match the file type, and let price decide only between tools that pass both. The “Which tool to pick, by situation” figure below maps common situations to one pick each.

Which tool to pick, by situation

Best for confidential text and code

If the text must not leave your computer, use a browser-only tool. sakuttoAI is the better fit for prose because it marks changes at the character level and lets you merge edits. CodeSamplez is the better fit for code and markup, thanks to syntax highlighting, whitespace handling, and .patch export.

Both are free with no account, so there is no reason to paste a confidential draft into a server-based checker. Diffchecker's desktop app is the paid alternative when you also need office formats offline.

Pick Draftable for scanned PDFs and Excel redlines

Diffchecker's free plan does read scanned PDFs and Excel files, but its caps bite on regular use. Character-level differences and formula-change detection stop after 10 tries a month. For a team that compares documents every day, Draftable's Business plan at $129 per user a year removes those caps along with the per-feature counting.

Choose Draftable's Legal plan when you need redlines in Word or Excel and integration with a document management system. Choose Diffchecker when you only compare office files now and then.

Mac users have fewer desktop diff-checker options

On a Mac, Draftable is out until its Mac build ships, and Diffchecker is the only tool here with a Mac desktop app. Everything else works through a browser, which runs the same on macOS as anywhere else.

For most Mac users that is enough. Use sakuttoAI or CodeSamplez for confidential text and code, and move to Diffchecker Pro + Desktop only if you need office formats offline.