The best Google Docs add-ons in 2026

Ten add-ons that install into Google Docs itself — writing, mail merge, signatures, citations and data. What each actually does in the document, what it costs, and the Apps Script ceiling that explains the slow ones.

Google Docs is deliberately spare, and the add-on Marketplace is where the missing features live. Three of them come up again and again: mail merge, which Docs simply does not have; AI writing, which Google now bundles for paying customers and a queue of third parties sell to everyone else; and getting real data into a document, which almost nothing does well. This page is sorted by which of those you actually need.

Sister directories: AI for Google Sheets, AI add-ins for Microsoft Word, and AI add-ins for Excel. If the job is specifically a chart, we have a walkthrough of how to put a graph in Google Docs without any add-on at all.

Fair warning: Quiriz is ours, and it is in this list. I have said plainly where the others beat us. Capability claims come from each add-on's own Marketplace listing or documentation, checked September 2026. Pricing in this category changes often — confirm on the vendor's page before buying, rather than trusting any roundup, this one included.

First, the thing nobody mentions: the six-minute ceiling

Almost every add-on in the Workspace Marketplace runs on Google Apps Script, and Apps Script cuts off a single execution at roughly six minutes. A sidebar cannot hold one long job open and wait.

Three consequences worth knowing before you judge any add-on on this page:

• Long jobs are loops, not one call. Anything touching many parts of a document — rewriting a long file, resolving lots of blocks, refreshing an entire report — has to be broken into a sequence of short server calls, one item at a time, with progress shown in the sidebar.
• "Slow" is often correct behaviour. An add-on that appears to grind through a big document one section at a time is usually doing the only thing the platform permits.
• Google's own features are not bound by this. Gemini in Docs is built in, not an Apps Script add-on, which is a structural advantage no third party can match.

None of this is a defect in any one product. It is the platform, and it applies to us exactly as much as to everyone else here.

Quick comparison table

Gemini in Docs (built in, not installed)

The job: draft, rewrite, summarise, translate, and generate images, without installing anything.

Gemini is woven into Docs itself — a Help me write prompt in the document, a side panel that can reference your Drive files, rewriting and tone controls, whole-document translation. Because it is native rather than an Apps Script add-on, it is not subject to the ceiling above, and it can reach your Drive in a way no third party can.

Where it stops: Google folded Gemini into the paid Workspace plans in 2025 and retired the standalone AI add-on SKUs, so in practice this is for paying Workspace customers. Access on a free personal Google account is limited. And like every general writing AI, it works with words: it can summarise the report you wrote, not compute the number that should be in it.

Pick it if you already pay for Workspace. You have it; use it before buying anything else.

Plus AI for Docs

The job: generate and edit long-form content inside the document.

One of the most-installed add-ons in the Marketplace and the strongest third-party writing option for Docs. You ask for a piece of content — a blog post, a policy, a section — and it drafts into the document, then rewrites, expands and edits what is already there. The same company's better-known product generates slide decks, and the Docs add-on carries that polish.

Where it stops: it is a content generator. It has no connection to your business data, and what it writes has to be checked like anything else a model wrote.

Pick it if you write a lot of long-form content on a free Google account, or you want a writing AI without a Workspace upgrade.

GPT Plus Docs and the ChatGPT sidebars

The job: OpenAI models in a Docs sidebar.

A cluster of add-ons putting GPT models beside the document — summarise, fix grammar, translate, expand, and in some cases generate images. They differ mainly in pricing, which models they expose and whether you can bring your own API key.

Where it stops: these are convenience wrappers around something you can already use in a browser tab. The value is the removed friction, which is worth real money to some people and nothing to others. Quality tracks the underlying model, so read the model list before the feature list.

Pick one if you want a specific OpenAI model in Docs and Gemini is not available to you.

Quiriz for Google Docs

The job: put answers from your own data into the document, and refresh them next month.

This is ours, so read it accordingly. Quiriz is not a writing assistant — it is built for the document that has to be produced again. You type a question where the answer belongs, select it, and press Chart or Table; the answer replaces the words that asked for it, computed from datasets you have uploaded to Quiriz rather than from a spreadsheet you maintain beside the document.

You can also draft the whole report before the month closes, leaving markers where answers go — =QUIRIZ("net sales by month", "chart") — and press Resolve markers to answer every one in a pass. Note the spelling: the Google add-ons use =QUIRIZ(...), while Excel and Word use =QUIRIZ.ASK(...).

The month after is the point. Every chart, table and figure remembers its question, so Refresh all asks them all again against the new data: charts gain their new months, the totals inside your sentences move, and your headings and prose stay where they are. Because Apps Script cuts off at six minutes, the refresh runs as a loop in the sidebar — one object per call, with a Stop you can press.

Where it stops, honestly: it will not improve your writing, draft a section, or fix your grammar — for that, Gemini or Plus AI is the right purchase and we are not competing for it. It needs your data in Quiriz first, which is genuine setup that only pays back if the document recurs. And if your numbers live in one small sheet you maintain by hand, Insert → Chart → From Sheets is less work than connecting anything.

Pick it if you write the same report every month and the tedious half is the numbers.

Mail merge: Yet Another Mail Merge, Autocrat, Avery

The job: the feature Google Docs does not have at all.

There is no Mailings tab in Docs, so mail merge here is entirely served by add-ons. All of them work the same way: a Google Sheet supplies the rows, a Doc supplies the template, and placeholders in the template are replaced per row.

• Yet Another Mail Merge — merge straight to Gmail, with tracking for opens and clicks, and a free daily quota. The default choice for sending personalised email.
• Autocrat — merge to documents. One Doc or PDF per row, saved to Drive and optionally emailed. This is the thing Word's own mail merge famously cannot do, and the reason plenty of people run their merges in Google rather than Office.
• Avery Label Merge — labels, badges and envelopes against Avery templates.

Where they stop: merge fields carry values from cells. They cannot carry an analysis or a chart of that recipient's last six months — see our mail merge guide for where that line falls, and sending a separate report to each client for the other side of it.

OneLook Thesaurus

The job: the right word, without leaving the document.

Small, free, and disproportionately good. Highlight a word and get synonyms, related terms, and — its real trick — reverse lookup, where you describe the idea and it finds words for it. No AI, no account, no subscription. If you write for a living, install it and forget about it.

DocuSign and e-signature

The job: send the document you are looking at for signature.

DocuSign's add-on lets you push a Doc into a signing workflow without exporting and re-uploading it, and several competitors do the same. Worth it only if you are already paying for e-signature; if you sign one thing a quarter, exporting a PDF is faster than installing anything.

Smallpdf

The job: convert, compress and sign PDFs from inside Docs and Drive.

A utility rather than a writing tool, and one of the most-installed things in the Marketplace because the job it does is so routine: turn this document into a PDF in a particular way, or turn that PDF into something editable. Free tier is limited by usage rather than by feature.

Paperpile, Zotero and citations

If you write research or academic documents, a citation manager is the add-on that matters and none of the AI ones come close in value. Paperpile is built for Google Docs specifically; Zotero reaches Docs through its connector. Both insert citations as you write and build the bibliography for you.

How to install an add-on

1. Open a Google Doc and go to Extensions → Add-ons → Get add-ons. The Workspace Marketplace opens inside the document.
2. Find the add-on and click Install.
3. Review the permissions, then grant them. The add-on appears under Extensions in every Doc on that account.

On a managed Workspace account, an administrator may have restricted installs — then the add-on has to be allow-listed or deployed domain-wide, and nothing you click in the document will change that.

Reading the permission screen

Worth thirty seconds, every time. Most add-ons need only the document you have open, which is the narrow, appropriate scope. A broader request — every file in your Drive, or your email — should have an obvious reason in what the add-on does. A mail merge tool asking for Gmail access makes sense; a thesaurus asking for it does not.

Marketplace add-ons go through Google's OAuth verification, but verification checks that the scopes are declared and justified by the vendor. It is not a judgement that you needed to grant them.

Which should you pick?

• You pay for Workspace. Use Gemini first. You are already paying for it.
• You are on a free Google account and want AI writing. Plus AI, or one of the GPT sidebars.
• You need mail merge. Yet Another Mail Merge for email, Autocrat when each recipient needs their own document or PDF.
• You write for a living. OneLook Thesaurus, free, today.
• You write research. Paperpile or Zotero, ahead of anything AI.
• You rebuild the same report every month. Quiriz for Google Docs — a different purchase from the writing tools rather than a competing one.

The question to settle before installing anything: is your problem the words or the facts? Most of this category answers the first. Sorting the list that way saves an afternoon of trials.

Frequently asked questions

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