Duck.ai lets you talk to Claude, GPT and Mistral models through DuckDuckGo's anonymizing proxy, with no sign-up, chat history kept on your device, and providers contractually barred from training on your prompts.
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Duck.ai is a DuckDuckGo feature for holding private conversations with third-party AI chat models, with DuckDuckGo standing between the user and the model provider. It opens at duck.ai in any browser, needs no account, and answers with models built by Anthropic, OpenAI, Mistral AI and Google rather than one DuckDuckGo trained itself. This DuckDuckGo AI tooling sits beside the search engine rather than replacing it.
That intermediary position is the whole product. A prompt travels not to OpenAI or Anthropic but to DuckDuckGo, which strips identifying metadata and re-issues it under its own name. The model still reasons, but never learns who asked.
Without paying anything, the roster covers Claude 4.5 Haiku, Mistral Small 4, GPT-5.4 nano, GPT-5.4 mini, gpt-oss-120b and Gemma 4 31B, the last two hosted by Tinfoil.sh. These are small and mid-sized rather than frontier models — the honest trade for a no-signup service.
The Mistral models travel under the Apache 2.0 licence, a detail that matters mainly to anyone auditing what licences their organisation's tooling depends on.
Model switching is the axis everything else turns on, because the roster changes with the plan rather than with the task. Plus adds GPT-5.4 and Claude Sonnet 4.6; Pro adds Claude Opus 4.8, a higher reasoning effort setting than Plus allows, and twice the Plus allowance. The interface is identical between tiers — only model names and session length change.
Recent Chats keeps history on the device, so the archive is only as portable as the browser profile holding it. Five chats can be pinned, and pinning is also what protects them from the Fire Button, which otherwise wipes the list in one click.
Sync and Backup moves that archive to encrypted server storage whose key never leaves the user's devices, so DuckDuckGo holds ciphertext it cannot read. Chats parked in Sync and Backup are deleted automatically after eighteen months without access, making it a syncing mechanism rather than a permanent archive.
PDF page ceilings climb with the plan: fifteen pages free, thirty-five on Plus, fifty on Pro. Upload support is model-dependent rather than universal, so switching models mid-task can remove the attachment button entirely.
Image generation sits behind a separate New Image entry and burns its own daily allowance, distinct from the chat counter. Follow-up prompts refine an image already produced.
Spoken replies stream through an encrypted relay and are never written down as audio. Only the text transcript persists, locally, and only if recent-chat saving is on. Dictation works the same way.
The workflow that actually pays off here is the comparison run, not the long single-model session. Because the model selector sits above the same conversation, one question can go to a Claude model and an OpenAI model back to back without a second account.
Drafting under confidentiality fits best. A prompt naming an unannounced product, a salary figure or a health question reaches the model with the IP address already gone — a materially different exposure profile from a logged-in account tied to a billing email.
Document triage is the second. A fifteen-page contract fits even the free ceiling, and asking three models to summarise one clause is a cheap way to catch a confabulation. The analyst's workflow does not fit: spreadsheets are rejected.
Voice practice is a quieter third. Rehearsing a difficult conversation aloud leaves only a deletable transcript, or nothing at all if recent-chat saving is off, because the spoken reply is never written down.
Whatever the case, the thread lives where the browser lives. Recent Chats keeps the archive on the device, so a session worth returning to should be pinned on the machine that produced it.
The clearest way to decide is to ask what would have to be true for the bundle to be worth its price. Duck.ai's paid capability arrives inside a subscription that also contains a VPN, Personal Information Removal and Identity Theft Restoration, so the question is never whether the AI alone justifies the money.
The case for private AI chat is people who type things they would not want attached to an identity, and who need drafting, summarising and explanation rather than long autonomous work. It fits people who already wanted a VPN, since the AI then arrives bundled, and anyone testing several models against one prompt without maintaining several accounts.
No developer API exists, so nothing can be built on top of the anonymized pipe. A team wanting to script against these models has to go to the providers directly, and automated querying is prohibited by the terms anyway.
Anyone already paying for a VPN elsewhere ends up buying that capability twice — not a hidden cost, but a real one against a standalone AI subscription at a similar price.
Regulated decisions are off the table by contract, not by capability. Legal, financial and medical advice, creditworthiness assessment, admissions and testing, housing, employment and government decision-making are all excluded, which removes most of the enterprise use cases that would otherwise justify a Pro seat.
The floor is thirteen where local law allows it, with guardian permission required below the local age of majority, so classroom deployment has to be checked against local rules before it is planned.
Reaching Duck.ai never requires an account, and the entry points multiply rather than replace each other. The web address works in any browser. The DuckDuckGo browser adds a dedicated button, and the search results page carries further buttons that turn a search into a conversation.
All are optional literally: the button can be added or removed in browser settings, the search-page buttons hidden in search settings.
| Access route | Account needed | Notes |
|---|---|---|
| duck.ai in any browser | No | Direct entry, history stored in that browser |
| DuckDuckGo browser button | No | Toggleable in browser settings |
| Search results page buttons | No | Hideable in search settings |
| Sync and Backup across devices | Subscription account | Encrypted, key held on device, 18-month idle deletion |
| Developer API | Not available | No public API exists |
Because history is tied to the browser by default, moving between laptop and phone means losing the thread or turning on Sync and Backup — the cost of the local-first design.
Nothing about Duck.ai is sold on its own, and that single fact decides most of the cost question. The free tier is genuinely free and accountless, which is what makes AI chat without account access possible at all; everything above it arrives inside the wider DuckDuckGo subscription.
Independent testing in July 2026 recorded Plus at 9.99 USD monthly or 99.99 USD annually and Pro at 19.99 USD monthly or 199.99 USD annually, with UK pricing at the same figures in pounds and most of the EU in euros. Those are a reviewer's recorded prices at that date, and the currency symbols are not interchangeable even where the digits match.
| Tier | Recorded price | Models added | Usage position |
|---|---|---|---|
| Free | 0 | Claude 4.5 Haiku, Mistral Small 4, GPT-5.4 nano and mini, gpt-oss-120b, Gemma 4 31B | Daily cap, figure unpublished |
| Plus | 9.99 USD monthly / 99.99 USD yearly | GPT-5.4, Claude Sonnet 4.6 | Higher than free, plus a weekly reserve |
| Pro | 19.99 USD monthly / 199.99 USD yearly | Claude Opus 4.8, higher reasoning effort | Twice the Plus allowance |
Subscribers hold a daily allowance and a weekly one behind it, with the daily counter rolling over at midnight UTC and the weekly counter on Sunday. When the daily figure runs out, the session draws on the weekly reserve until that too is gone. Consumption of both is visible in settings, the only quantitative view offered.
The free daily cap is never published as a number, so planning high-volume work around it is guesswork.
Alternatives split along one line: whether the text leaves the machine at all. Locally run open-weight models remove the trust question structurally, at the cost of hardware and setup. Hosted assistants that pledge not to train keep the convenience and ask for trust in a policy.
Duck.ai takes a third position among anonymous AI chat options: hosted, but with identity removed before the host sees anything. Against a standalone AI subscription at a similar price, the comparison turns on whether the bundled VPN and identity services are wanted; against a direct provider account, on whether an API is needed — the one thing Duck.ai cannot supply.
Spreadsheets cannot be uploaded at all, which quietly rules out the most common analyst workflow. This is not a size or plan limit; the format is unsupported everywhere.
The daily cap itself is never published as a number, and the vendor also declines to describe the mechanism that enforces it, arguing that publishing the method would hand it to bad actors while insisting the method stays fully anonymous. That leaves no way to budget a heavy day in advance.
A VPN or a cellular connection can trip the usage error in the first minute of a session. The anonymous enforcement mechanism reads a shared exit address as heavy usage; the suggested fixes are changing VPN location or moving to Wi-Fi — an awkward interaction for a privacy product.
Detail and specificity are explicitly disclaimed as signals of accuracy: DuckDuckGo warns that an answer can look complete and precise while being wrong, and disclaims responsibility for coding errors or vulnerabilities that come out of it. Verifying against another source is the user's job.
A share link carries its own decryption key, so possession of the URL is possession of the conversation. Anyone with the link can read and continue the chat. Links expire after thirty days or when revoked in settings, whichever is first. Generated files ride along with a shared link while uploaded ones stay behind, so a shared thread can be missing exactly the document that made it make sense.
Automated querying and rate-limit circumvention are prohibited outright, alongside developing or offering AI services on top of Duck.ai. One paying subscriber reported a sixteen-thousand-character ceiling on a single message and a conversation length exhausted after a few exchanges; that is a single community report rather than a specification, and the official pages quantify neither ceiling.
Published rosters disagree, and the gap is worth naming rather than smoothing over. A July 2026 independent review recorded GPT-4o mini, Llama 4 Scout and Claude Opus 4.7, while the current official help page lists Gemma 4 31B, Mistral Small 4 and Claude Opus 4.8 atop Pro. The roster moves faster than published comparisons, so check any model list in the product before it drives a purchase.
The anonymization happens before the prompt leaves DuckDuckGo, not after it arrives at the model provider. Metadata carrying personal information, the IP address included, is removed first, so requests reach Anthropic, OpenAI, Azure OpenAI and together.ai looking like DuckDuckGo's traffic. Anything personal typed into the prompt still travels: the anonymity covers who asked, not what was said.
Providers are contractually bound to delete what they receive once it is no longer needed to answer, and within thirty days at the outside, with narrow carve-outs for safety and legal compliance. They are also barred from using prompts and outputs to train their models.
Two official pages state that retention rule differently: the help centre says every model provider deletes prompts and responses immediately after generating a reply, described as Zero Data Retention, while the terms page keeps the looser at-most-thirty-days wording. Both are vendor statements and neither supersedes the other, so the stricter promise should not be assumed without checking the per-chat privacy dialogue.
Models processed inside a Trusted Execution Environment carry a zero provider visibility label, meaning the host cannot read the prompt or the answer. That is stronger than a contractual promise, and currently applies to a subset of the roster.
Prompts and outputs stay the user's property, and the licence taken over them is limited to delivering the service.
No. The free tier opens at duck.ai and works immediately with no email address, password or payment method. An account matters only for a subscription, unlocking the larger models and Sync and Backup.
No. DuckDuckGo's agreements with the model providers bar them from using prompts and outputs to develop or improve their models, and require deletion once the data is no longer needed to produce a response, within thirty days at the outside.
DuckDuckGo does not publish the free-tier number, stating that keeping the enforcement method opaque is part of preventing abuse. Subscribers see daily and weekly consumption in settings, and the daily counter resets at midnight UTC.
Yes, within a plan-dependent page ceiling: fifteen pages free, thirty-five on Plus, fifty on Pro. Upload support also depends on the selected model, and spreadsheets are not supported in any tier.
No. Duck.ai is a consumer interface with no public API, and the terms separately prohibit automated querying and building AI services on top of it. Development work goes to the model providers directly.
It contains its own decryption key, so anyone holding the link can read the conversation and continue it as a chat of their own. The copy is deleted after thirty days, or earlier if the link is revoked in settings.
No. The terms exclude legal, financial and medical advice, creditworthiness determination, admissions and testing, housing, employment and governmental decision-making, regardless of plan.
By default it stays in the browser, so clearing browser data loses it and a second machine starts empty. Sync and Backup optionally stores it encrypted on DuckDuckGo's servers with the key held only on the user's devices, deleting anything untouched for eighteen months.
