Set up thirds.ai in Zapier: make branded PDFs and images from a Zap

You make a branded PDF in Zapier with the thirds.ai app. It adds two actions, Make a PDF and Make an Image, that fill a design you saved on thirds.ai with the details from each Zap run. thirds.ai is a web app where you pick a designer-made template or make your own, add your logo, colours, and fonts, and send out a beautiful PDF or image. You make and edit the design on thirds.ai, and Zapier only fills it in. So a new paid order can turn into an invoice that looks agency-made, and nobody copies numbers by hand. Each finished file costs one credit, and a verified free account gets 50 credits a month.

The thirds.ai app on Zapier is private for now, so you join it from our invite link before you add it to a Zap. See the invoices, certificates, and posts a Zap can make on the thirds.ai for Zapier page. If you'd rather build the request yourself with Zapier's own web request step, the API workflow guide shows that way.

Make your invoice design on thirds.ai first

You make the design on thirds.ai first, because the Zapier app can only fill a design you already saved. It takes three steps in the editor, and you need a free thirds.ai account. The Design studio invoice template is a good start for a Zap that bills clients, because every client then gets the same polished page.

1. Open the Design studio invoice template and click Use this template. Sign in and verify your account first if you need to.
2. Make the page yours. Open the Data tab to see each detail that Zapier will fill in, such as the client, the invoice number, and the total. Click Preview with data above the canvas to check the page. The preview is free.
3. Click Export, then Save and export PDF, and download your first invoice.

Saving puts the design in your saved templates, where the Zapier app finds it. When you change the design later and save it again, your next Zap run uses the new version.

What the thirds.ai Zapier app can and can't do

The thirds.ai Zapier app can fill one of your saved designs and give you a PDF or image, but it can't make or change a design. It makes one file each time the Zap reaches its step. It adds two actions and no trigger, so another app, such as your shop, your form, or your spreadsheet, starts the Zap. The app sees only the designs and files in the thirds.ai account that owns your API key.

The app can:

• List your saved designs, so you pick one by name.
• Show one box for each detail your design takes, such as the client name and the total. A list, such as invoice rows, shows as line items.
• Make a PDF, or a PNG, JPEG, or WebP image.
• Use your newest saved version, or one version you name.
• Name the file and hand it to the next step, such as an email or a cloud folder.

The app can't:

• Make or change a design. You do that on thirds.ai.
• Make AI pictures, use the AI chat, or switch to another brand kit.
• Send email, post to social networks, or store your files for good. Other Zapier apps do those steps.
• Edit a PDF you already have.

Connect thirds.ai to Zapier

You connect thirds.ai to Zapier in four steps, and then every Zap in your Zapier account can use it. You need a thirds.ai account with a verified email address and a Zapier account. Zapier's guide to sharing a private integration says an invite link opens the app's page, where you follow Zapier's steps to accept it (checked 30 September 2026).

1. Open the thirds.ai Zapier invite link and accept the invite.
2. On thirds.ai, open API keys, make a key named Zapier, and copy it. The key starts with thirds_sk_, and you see the whole key only once.
3. In the Zap editor, add an action step, search for thirds.ai, and pick Make a PDF or Make an Image.
4. Connect a new account and paste the key into API key. Zapier checks the key by reading one saved design, and the check spends no credits.

Keep the key out of Zap notes and shared screenshots. If the key leaks, delete it on the API keys page and make a new one.

Make a PDF or image in a Zap

You make a file in a Zap by picking your saved design and matching its details to values from earlier steps. It takes five steps, and you need the connection and one saved design.

1. In Template, pick your saved design.
2. Leave Template version blank to use the newest version you saved.
3. Fill in each detail. Map values from earlier steps, such as the customer's name from your shop or the total from your payment app. For a list, add one line item for each row.
4. For Make an Image, pick PNG, JPEG, or WebP in Image type. Leave Width in pixels and Height in pixels blank to use your design's own size, so a square post stays square.
5. Type a File name if you want one, then test the step.

If a design has no list of details yet, Zapier shows one Details box instead. Type the values there as JSON, such as {"client_name": "Rosa Diaz", "total": 480}.

The step gives the next step these values:

Use File in a later step. It gets a fresh link each time, so it still works after the 15-minute link ends.

Zapier retries never charge you twice

A Zapier retry never charges you twice, because the thirds.ai app sends a retry key with each file. The app makes the key from your Zap and everything you put into the step. When Zapier retries or replays the same step, it sends the same key, so thirds.ai hands back the file it already made. You pay once, and a file that fails costs nothing.

Some files take longer than 25 seconds. The step then asks Zapier to try again a little later with the same key, so you still get one file and one charge.

The same Zap with exactly the same details also gets the same file back for 24 hours. To make a fresh copy of a file with the same details, change the File name, for example by adding today's date. The retry and download guide explains retry keys in more depth.

How long thirds.ai keeps your files

How long thirds.ai keeps each finished file depends on your plan, and the pricing page shows the time for each plan. The File kept until value tells you the date for each file. To keep a copy for longer, add a step that saves the file to your own storage.

Fix a failed thirds.ai step

A failed thirds.ai step shows a message that says what to fix, and each message has one fix. Look up any error code in the error list.

Privacy, terms, and help

Our privacy policy, Terms of Service, and support page all cover the thirds.ai Zapier app, including files you make through Zapier. The app sends thirds.ai only the design you pick and the details you map, and thirds.ai deletes those details when your file is done. The privacy policy says what we keep and for how long. For help with the app, a key, or a failed step, contact support.