How to connect Gemini to Mighty

Knowledge base

Last updated 20/10/2026

Let Google Gemini read your figures and prepare drafts for you, by signing in to Mighty from Gemini.

Gemini is an AI assistant made by Google. When you connect it to Mighty, you can ask it questions about your company in plain words, and it reads the answer from your own figures. It can also prepare work for you to check, such as a draft invoice.

At the moment Google only lets people in the US add their own connections to Gemini, using a personal Google account. If you are in the UK, or you use Gemini through a work or school account, you can't connect it to Mighty yet. You can use Claude or ChatGPT instead.

What you need first

Google sets these rules, not Mighty:

A personal Google account. Work and school accounts can't add their own connections.
To be 18 or over and in the US.
Keep Activity switched on in your Gemini settings.
A computer. You add the connection at gemini.google.com, then it also works in the Gemini app on your phone.

You also need your Mighty email address and password, and about 5 minutes.

How the connection works

You don't need a password or key from Mighty for Gemini. Instead, Gemini sends you to Mighty to sign in, the same way some websites let you sign in with Google. You then choose which company Gemini can reach and select Allow.

Gemini works as you. It can see the company you chose and nothing else. If you look after more than 1 company in Mighty, connect Gemini once for each company.

What Gemini can do in Mighty

Area	What Gemini can do	Can it change your accounts?
Dashboard	Read your bank balance, profit, tax estimates, dividends available and unpaid invoices. It can also refresh those figures.	No.
Reports	Read your profit and loss report (your income and costs), your balance sheet (what the company owns and owes) and your trial balance (the balance on every account), for any period.	No.
Sales invoices	List and read your sales invoices (the bills you send customers so they pay you), and create a new one.	A new invoice is saved as a Draft unless you ask Gemini to raise it. A raised invoice counts in your accounts straight away.
Bank transactions	Look through the transactions waiting for you, read the receipts attached to them, and suggest what each one was for.	No. Gemini can only save a suggestion as a draft. You approve each one in Mighty.
Mileage	List your mileage claims (business journeys in your own vehicle that the company pays you back for), look up the distance between 2 places, and record a new claim.	Yes. Mighty has no draft mileage claim, so a claim Gemini records counts in your accounts straight away. To remove one, delete it on the Mileage Claims screen.

Gemini cannot approve a bank transaction, delete anything, pay anyone or send anything to HMRC (the UK tax authority). Gemini asks you to confirm before it changes anything in Mighty.

Things you can ask

Type @ and choose Mighty first, so Gemini knows to use it.

"What is my bank balance in Mighty?"
"Which of my invoices are overdue, and how much do they add up to?"
"Show me this year's profit and loss next to last year's."
"Create a draft invoice to Acme Ltd for 3 days of consultancy at £600 a day."

Gemini can make mistakes. Check a draft before you approve it, the same way you would check work from a new member of staff.

Turning the connection off

To stop Gemini reaching your company, go to Company Settings, open the Other tab and select API Keys. Under Connected apps, select Revoke next to Gemini, then confirm.

The Connected apps list with the Revoke button highlighted next to Gemini

Gemini loses access straight away. To use it again, connect it again from Gemini.

You can also remove Mighty in Gemini, under Settings, then Connected Apps. Removing it there does not turn the connection off in Mighty, so revoke it in Mighty as well.

Common questions

Why can't I see Custom apps in Gemini?

Google only shows it to people who meet the rules in What you need first. The most common reasons are being outside the US, using a work or school account, or having Keep Activity switched off.

Start again from Gemini. The link it opens can only be used once, and only for a few minutes.

Mighty only lists the companies you can connect. If you only have access to some areas of a company, you can't connect an assistant to it, because Gemini would see the whole company. Ask the company's owner or your accountant to connect it instead.

Can someone else see that Gemini is connected?

Yes. Everyone who can open API Keys for the company sees the connection under Connected apps, with who connected it and when it was last used. Any of them can revoke it.

How to do it in Mighty

Step 1

Open Connected Apps in Gemini Go to gemini.google.com on a computer. At the bottom of the menu, select Settings, then Connected Apps.

Step 2

Add a custom app Under Custom apps, select Add a custom app.

Step 3

Enter the Mighty address Enter https://api.mightyaccounting.com/mcp as the address, then select Next. You don't need to fill in anything under Advanced features.

Step 4

Sign in to Mighty Gemini opens Mighty's sign-in page. Sign in with your Mighty email address and password, the same way you sign in every day.

Step 5

Choose your company and select Allow Mighty shows what Gemini will be able to do. Choose the company to connect, then select Allow. Mighty sends you back to Gemini.

Step 6

Check that it works Start a new chat in Gemini. Type @, choose Mighty, then ask: What is my bank balance in Mighty? Gemini shows the figure from your dashboard.

Step 7

Check the connection in Mighty In Mighty, open Company Settings, then the Other tab, then API Keys. Gemini is listed under Connected apps as Active.

What you need first How the connection works What Gemini can do in Mighty Things you can ask Turning the connection off Common questions Why can't I see Custom apps in Gemini?What if the Mighty sign-in page says the sign-in expired?Why can't I see my company when I sign in?Can someone else see that Gemini is connected?