Spot the seam before your print proof does.

A tile can look finished and still show a line once it repeats. Drop one in to see where it breaks, then fix the seam and get the same tile back at the exact pixel size.

Drop your pattern here

PNG, JPG or WEBP · up to 40 MB · 64 to 3600 px a side

Free check, no account

No file to hand?

Close up: a faint seam where the copies meet

See this sample fixed

The same tile at the same size, with the line gone.

The sample from the checker above, fixed as a straight repeat and shown where four copies meet.

Before: four copies of the sample meeting in the middle. Flowers and leaves stop short along a vertical and a horizontal line. — Drag the divider. The red ticks point at the two seams of the original.

After the fix: the same spot. The flowers and leaves run on across both lines. — Drag the divider. The red ticks point at the two seams of the original.

The sample, before and after

BeforeFaint seam on both edges.AfterPassed the seam check as straight.

Size: 1024 x 1024 px, in and out
Left and right edge: Faint 1.42 to Clean 0.99
Top and bottom edge: Faint 1.36 to Clean 1.02
Changed: 15% of the image, a band along the edges
File: Lossless PNG

The fixed tile with everything the fix left alone shown pale. Only a band along the edges is in full colour. — What the fix changed, in colour. Every pale pixel is exactly as it was in the original.

Passes the seam check. Every result you download passes the seam check on its tile edges for the repeat you chose.
Your pixels stay yours. Outside the changed area, every pixel is your original, and the width and height stay exactly the same.
No pass, no charge. When no version passes the check, you get no image and the fix costs nothing.

Generated the tile? Check it before it goes to print.

A tile can look right on its own and still show a line once it repeats, like the sample above. Made it in Midjourney, ChatGPT or an upscaler? Drop it in the checker, or let your agent check every tile it makes. Making it again does not promise a cleaner tile, so check the file you will print.

Printify's own guide warns: “Upscaling re-processes the image and breaks the seamless edge.”

Check a tile How agents use MakeSeamless

The sample tile on its own. Nothing about it looks wrong. — On its own the tile looks finished. The check reads the edges where copies of it meet.

Your agent can check a tile in one request

The checker on this page runs on the public MakeSeamless API. An agent, a script or an automation can send the same check with no account and no key, and get the seam report back as JSON. Make it a step your agent takes before any tile is called seamless, uploaded or printed.

Before: four copies of the sample meeting in the middle, with a faint line where they meet. — Before

No key to check.
POST /v1/check takes the image and returns a verdict for straight, half-drop and half-brick, with how strongly each edge breaks and where.
Cost before the fix.
A fix uses 1 credit, or 3 for a tile over 2048 px on either side. When an account is short, the API says how many credits the fix needs.
No pass, no charge.
Every fixed tile has passed the seam check for its repeat. A fix that ends without a passing result costs nothing, and the same fix of the same file returns the stored result at no charge.
Built to be read by machines.
The whole contract is one OpenAPI 3.1 file, and every page has a Markdown version.

Paste into a coding agent

Read https://makeseamless.com/llms.txt, then use the MakeSeamless API to check ./peony-pattern.png. Tell me which repeat types it passes and where any seam is.

Request

$ curl https://makeseamless.com/v1/check \
    -F file=@peony-pattern.png

Python, with requests

import requests

with open("peony-pattern.png", "rb") as f:
    r = requests.post(
        "https://makeseamless.com/v1/check",
        files={"file": f},
    )
report = r.json()
print(report["satisfied"], report["summary"])

Node 20 or later

import { readFile } from "node:fs/promises";

const png = await readFile("peony-pattern.png");
const form = new FormData();
form.append("file", new Blob([png]), "peony-pattern.png");

const res = await fetch("https://makeseamless.com/v1/check", {
  method: "POST",
  body: form,
});
const report = await res.json();
console.log(report.satisfied, report.summary);

Response200 · JSON

{
  "input": { "width": 1024, "height": 1024, "format": "PNG", … },
  "verdicts": {
    "straight": {
      "verdict": "minor",
      "edges": [
        { "edge": "vertical", "verdict": "minor",
          "anomaly": 1.4236, "broken": [[0, 1024]], … },
        { "edge": "horizontal", "verdict": "minor",
          "anomaly": 1.3601, "broken": [[0, 1024]], … }
      ]
    },
    "half_drop": { "verdict": "bad", … },
    "half_brick": { "verdict": "bad", … }
  },
  "satisfied": [],
  "summary": "Does not tile seamlessly as any checked repeat type. …"
}

Fixes through the API use the same credits as the app. Breaking changes only ever arrive under a new prefix, such as /v2.

Prompts to copy

Paste one into your coding agent. Each prompt names makeseamless.com, so the agent goes straight to our API and docs.

Check one tile

Using the MakeSeamless API (makeseamless.com), check ./peony-pattern.png and tell me which repeat types it passes.

You get: seam report
Check a folder before upload

Using the MakeSeamless API (makeseamless.com), check every PNG in ./etsy-papers as a straight repeat. Write the file name, verdict and broken edge of each to seam-report.csv.

You get: seam-report.csv
Check what you just generated

Using the MakeSeamless API (makeseamless.com), check each tile in ./out as a half-drop repeat before you call it seamless.

You get: seam report
Fix the ones that fail

Using the MakeSeamless API (makeseamless.com) and my key in MAKESEAMLESS_API_KEY, fix the tiles in ./etsy-papers that fail as straight, save each result as name-seamless.png, and tell me the credits used.

You get: peony-seamless.png

How it works

One tile in, one seamless tile out, at the size you made it.

Drop one tile

PNG, JPG or WEBP up to 40 MB, as you would repeat it. The check is free and needs no account.
Read the seam report

A verdict for straight, half-drop and half-brick, how strongly each edge breaks, and red marks where.
Fix and download

Sign in, fix the repeat you sell in, compare before and after, and download a PNG at the exact pixel size. Usually ready in under 30 s.

Straight, half-drop or half-brick

One check reads all three repeats and gives each its own verdict. Choose the repeat you sell in, and the fix makes the tile edges meet for it. Three real results, shown tiled.

Straight

Copies sit side by side in rows and columns.

Left and right edge: Faint 1.42toClean 0.99
Top and bottom edge: Faint 1.36toClean 1.02
Changed: 15% of the image

Floral tile, 1024 x 1024 px in and out.

Before: the floral tile repeated straight. A faint line runs where copies meet, marked in red. — BeforeFaint seam on both edges.

After: the fixed floral tile repeated straight. Flowers and leaves run on across every join. — AfterPassed the seam check as straight.

Half-drop

Every other column drops by half the tile height.

Left and right edge: Strong 2.25toClean 1.09
Top and bottom edge: Faint 1.29toClean 0.97
Changed: 14% of the image

Kids print, 1024 x 1024 px in and out.

Before: a monster print repeated as half-drop. Monsters are cut in half along the vertical join, marked in red. — BeforeVisible seam on both edges.

After: the fixed monster print repeated as half-drop. Every monster is whole across the joins. — AfterPassed the seam check as half-drop.

Half-brick

Every other row shifts by half the tile width.

Left and right edge: Faint 1.49toClean 1.00
Top and bottom edge: Strong 2.09toClean 1.00
Changed: 19% of the image

Spice flat lay, 1024 x 1024 px in and out.

Before: a spice print repeated as half-brick. Bowls and chillies break off along the joins, marked in red. — BeforeVisible seam on both edges.

After: the fixed spice print repeated as half-brick. Bowls, chillies and spices continue across every join. — AfterPassed the seam check as half-brick.

Pricing

Checks are free and unlimited. Fixes use credits.

Yearly is 20% off

Free

Check every pattern, as often as you like.

Unlimited seam checks

No account or key needed.

Check a pattern

Straight, half-drop and half-brick
Where each edge breaks, and how strongly
Checks from the app, the API or an agent

Pro

For sellers who fix patterns every week.

$19/month

50 credits a monthBilled monthly

1 credit = 1 fix. A tile over 2048 px on either side uses 3 credits.

Credits

Need more? Top up any time at $0.380 a credit.

Credits renew every month
Top-ups at your tier's credit price
Before and after compare
PNG at your exact pixel size
A fix that fails costs nothing

Enterprise

For platforms and teams with steady volume.

Custom

Credit volume and price set with you.

Contact sales

Everything in Pro
Credit volume to match your catalogue
The same /v1 API as the app

Checks never use credits. A fix that ends without a passing result costs nothing.

Checks are free for people and agents alike. A fix costs the same credits from the app, the API or an agent.

Questions

Something else? Write to hello@makeseamless.com.

How do credits work?

1 credit = 1 fix. A tile larger than 2048 px on either side costs 3 credits, and you see the cost before you fix. A fix that fails costs nothing, and running the same fix on the same file again returns the stored result at no charge. Checks never use credits.

What does MakeSeamless do to my tile?

It works on the tile you already made. It checks where the tile breaks when it repeats and fixes that seam. The width and height stay exactly the same, and outside the changed area every pixel is your original.

Why does my pattern show a line when the tile looked seamless?

A tile can look finished on its own and still break where its copies meet: a faint white line, a grid of pixel lines, or edges a few pixels off. The line often shows only at print size, on the proof or on the product, and resizing or exporting a tile can open a seam that was not there before. Check the file you will print. The check is free and reads every edge for straight, half-drop and half-brick.

How do I know a fixed tile is really seamless?

Every result you download has passed the seam check on its tile edges for the repeat you chose, and it shows the seam report before and after. When no version passes, you get no image and the fix costs nothing. Outside the changed area every pixel is your original, and the width and height stay exactly the same.

Should I check a tile before I upload it to Spoonflower, Etsy or a print-on-demand shop?

Yes, each time the file changes. A seam found on a sample, an order or a buyer's product is found after the money is spent. Check after you make or resize a tile and before you upload it. The check is free and needs no account, and you fix only the repeats you sell in that fail.

What does the check look at?

The edges where copies of your tile meet: left against right, top against bottom, and the half-tile offsets of half-drop and half-brick. For each repeat type you get a verdict, how strongly each edge breaks, and where along the edge the break runs.

Do I need an account?

Not to check. Checks are free, unlimited and need no account. To fix, sign in with Google or with a sign-in link sent to your email, and use the credits of a Pro plan.

What do I get back from a fix?

A lossless PNG with exactly the same width and height as your tile, which passes the seam check on its tile edges for the repeat you chose. The result shows how much of the image changed and where. Outside that area, every pixel is your original. The file carries an sRGB tag and none of your original's metadata.

What if the whole tile has to change?

Some tiles can only be made seamless by rebuilding the whole tile. The result then says so, with a changed area of 100%: “Rebuilt as a whole so it tiles. Every pixel differs from your original.” If the tile was also resampled, it says “Rebuilt and resampled, so every pixel changed.” The pixel size stays exactly the same.

What if the fix cannot make it seamless?

Then you get no image and the fix costs nothing. A result that fails the seam check is never handed back.

What does the Free plan include?

Unlimited seam checks with no account: a verdict for straight, half-drop and half-brick, with how strongly each edge breaks and where. Agents and scripts can send the same check through the API with no key. Fixes use credits, which come with Pro.

What does Pro cost?

$19 a month for 50 credits, $49 for 135, $99 for 280 or $149 for 430. Yearly is 20% off: $15, $39, $79 or $119 a month, billed once a year with 12 months of credits.

How do yearly billing and top-ups work?

Yearly is 20% off the monthly price and gives you 12 months of credits for each year. On Pro you can top up any time at your tier's credit price: $0.380, $0.363, $0.354 or $0.347 a credit.

Which files and sizes work?

PNG, JPEG or WebP up to 40 MB, at least 64 x 64 px. Checks take images up to 64 megapixels and fixes take tiles up to 3600 x 3600 px.

Can I use it from my own code?

Yes. The app runs on the same versioned /v1 API: a check is one request, and a fix is a job you start, follow and download, using the same credits.

Can my AI agent use MakeSeamless?

Yes. Any agent that can send a web request can check a tile with POST /v1/check, with no account or key. To fix, it uses an API key from your account and the same credits as the app. The agent guide has the steps and prompts to copy.

Do fixes through an agent or the API cost more?

No. One credit is one fix wherever it starts, or 3 credits for a tile over 2048 px on either side. You see the cost before the fix, and a fix that fails costs nothing.

Check your next pattern before it goes to print.

Free, no account, and the seam report comes straight back.

Check a pattern

Using an AI agent? Read the agent guide

Spot the seam before your print proof does.

Seam report

The same tile at the same size, with the line gone.

The sample, before and after

Generated the tile? Check it before it goes to print.

Your agent can check a tile in one request

No key to check.

Cost before the fix.

No pass, no charge.

Built to be read by machines.

Prompts to copy

Check one tile

Check a folder before upload

Check what you just generated

Fix the ones that fail

How it works

1Drop one tile

2Read the seam report

3Fix and download