# Issue attaching a generated PDF to email (SMTPAttachments) **URL:** \ **Category:** How do I?\ **Created:** [March 16, 2026, 9:24pm UTC](https://www.five.org/t/issue-attaching-a-generated-pdf-to-email-smtpattachments/630 "2026-03-16T21:24:42Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![JeanXXIV](https://yyz2.discourse-cdn.com/flex030/user_avatar/www.five.org/jeanxxiv/32/548_2.png) [@JeanXXIV](https://www.five.org/u/JeanXXIV)\ **Post date:** [March 16, 2026, 9:24pm UTC](https://www.five.org/t/issue-attaching-a-generated-pdf-to-email-smtpattachments/630/1 "2026-03-16T21:24:42Z")
Hello, I am trying to attach a PDF generated with **pdf-lib** in my Five application and send it by email using `SMTPAttachments`. The PDF itself is valid. If I download it locally from the browser it opens correctly in Foxit Reader. However, when I attach the same document to an email in Five, the attachment received in the email is always about **1 KB** and the PDF viewer reports that the file is corrupted or not a valid PDF. Here is the workflow I am using: **Client side** I generate the PDF with pdf-lib: ```auto let pdfBase64 = await pdfDocGlobal.saveAsBase64(); if (pdfBase64.indexOf(',') > -1) { pdfBase64 = pdfBase64.split(',')[1]; } five.setVariable('PdfPiecesGlobal', pdfBase64); ``` The Base64 string is received correctly on the server side. For example I logged: - Size: about 366,000 characters - Beginning of the string: `JVBERi0xLj` So the Base64 looks valid. **Server side** I attach the PDF like this: ```auto context.SMTPAttachments = [ reportResult.report, { filename: "Documents_Fusionnes.pdf", data: five.variable.PdfPiecesGlobal, encoding: "base64", contentType: "application/pdf" } ]; ``` The report generated by Five (`reportResult.report`) is attached correctly. But the generated PDF attachment always arrives corrupted and around **1 KB**. I also tried several alternatives without success: - using `content` instead of `data` - converting Base64 to byte arrays - using Uint8Array - generating the PDF server-side The result is always the same: attachment size about **1 KB**. My questions are: 1. Is it supported to attach a dynamically generated file (Base64 or bytes) using `SMTPAttachments`? 2. If yes, what is the correct format expected by Five for the attachment object? 3. Is there a recommended way to attach a PDF generated with a JavaScript library like pdf-lib? Thank you for your help! Jean ---
**Author:** ![eltonsantos](https://avatars.discourse-cdn.com/v4/letter/e/b19c9b/32.png) [@eltonsantos](https://www.five.org/u/eltonsantos)\ **Post date:** [March 16, 2026, 11:48pm UTC](https://www.five.org/t/issue-attaching-a-generated-pdf-to-email-smtpattachments/630/2 "2026-03-16T23:48:59Z")
Hi Jean, Thank you for sharing this scenario. You should be able to achieve it; once the data is in base64, it should be pretty much the same. Just for curiosity, have you compared the beginning of the string of the **pdfBase64** and the **reportResult.report** if they are different. Can you append the difference to the **pdfBase64** and give it another try? For example: This is the beginning of a string for a report result, it has **data:application/pdf;base64,** “data:application/pdf;base64,JVBERi0xLjcKJYGBgYEKC“ If you prefer, and for a better investigation, you can also send me the **pdfBase64** value\*\*,\*\* and if it’s possible, the client and server function to [elton@five.co](mailto:elton@five.co), so I can further investigate it. Regards, Elton S ---
**Author:** ![eltonsantos](https://avatars.discourse-cdn.com/v4/letter/e/b19c9b/32.png) [@eltonsantos](https://www.five.org/u/eltonsantos)\ **Post date:** [March 17, 2026, 4:26am UTC](https://www.five.org/t/issue-attaching-a-generated-pdf-to-email-smtpattachments/630/3 "2026-03-17T04:26:14Z")
Hi Jean, Below is one example of how you can achieve it: 1 - Generate the PDF via **pdf-lib.** In my example, I already have a PDF Base64 (raw). 2 - Call the callback function and pass the Base64 to it. ```auto function GeneratePDFClient(five, context, result) { //Base64-encoded PDF that includes metadata indicating it was produced by pdf-lib. const parms = { Base64PDF: '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' } five.executeFunction('GeneratePDFServer', parms, null, '', '', function (serverResult) { if (!serverResult) { five.showMessage('Error generating emails.'); } }); return five.success(result); } ``` 3 - In the server function, I am running a report, retrieving the Base64 string and appending the string to it ‘ **data:application/pdf;base64,** ‘. 4 - Then add both reports to an array and send them to the execution function. When I received the email, both PDFs opened without issue. ```auto function GeneratePDFServer(five, context, result) { //////////////////////////////////////////////////////////////////////////////////////////////// // Execute the report action //////////////////////////////////////////////////////////////////////////////////////////////// const reportResult = five.executeAction('StaffExtensionTestV2', {StaffExtension:"2122"}); five.log("Test....:") five.log(JSON.stringify(reportResult)) if (reportResult.isOk() === false) { return five.createError(reportResult); } const files = \[\] let base64PDF = context.Base64PDF; //prepend (add to the beginning) a string using simple string concatenation. base64PDF = \`data:application/pdf;base64,${base64PDF}\`; files.push(base64PDF) files.push(reportResult.report) //////////////////////////////////////////////////////////////////////////////////////////////// // The reportResult contains a parameter called report, which is the report result in the format // of a pdf (encoded as data url application/pdf mimetype) //////////////////////////////////////////////////////////////////////////////////////////////// const mailMergeContext = {SMTPToEmail: 'youremail@yourcompany.co', SMTPToName: "Staff", SMTPAttachments: \[...files\]}; const mailResult = five.executeAction('ExtensionReportEmail', mailMergeContext); if (mailResult.isOk() === false) { return five.createError(mailResult); } return five.success('Report has been sent'); } ``` This is the default function that attaches the files before the email is sent; this function is on the event ‘Do Merge Record‘, in the Mail Merge action, tab events. **Observation** : In this example, both files will have the same name, but you can change it. ```auto function DoAddAttachments(five, context, result) { if (context.Attachments && context.Attachments.length > 0) { for (let i = 0; i < context.Attachments.length; i++) { const attachment = context.Attachments\[i\]; five.addAttachment(five.toDataURL('application/pdf', attachment), 'StaffExtension'); } } return five.success(result); } ``` If you use a five.variable for the Base64 (raw), make sure you set this variable in the back, and retrieve it using five.getVariable(‘variableName‘). Please let me know if that helps you. Regards, Elton S ---
**Author:** ![JeanXXIV](https://yyz2.discourse-cdn.com/flex030/user_avatar/www.five.org/jeanxxiv/32/548_2.png) [@JeanXXIV](https://www.five.org/u/JeanXXIV)\ **Post date:** [March 19, 2026, 12:53am UTC](https://www.five.org/t/issue-attaching-a-generated-pdf-to-email-smtpattachments/630/4 "2026-03-19T00:53:40Z")
Hi Elton, My problem was here: `context.SMTPAttachments = [` `reportResult.report,` `{` ` filename: “Documents_Fusionnes.pdf”,` ` `**`data: five.getVariable('PdfPiecesGlobal'),` ` encoding: “base64”,` ` contentType: “application/pdf”`** `}` `];` I simply needed to use the string of my PDF and not to wrap it in an object, and add the “data:…” prefix. `context.SMTPAttachments = [` `reportResult.report,` **`“data:application/pdf;base64,” + five.getVariable('PdfPiecesGlobal')`** `}` `];` Thank you so much! My problem is finally solved!