PDF Server


The Form.io PDF Solution is a powerful tool with two options: PDF Server and PDF Server Plus. Please see the below description of each to see which aligns best with the requirements of the Application being built.

The Form.io PDF server is currently not compatible with Apple M1 chips and ARM64 architecture. The guide below will detail how to run this server on other systems like an Intel Mac or Linux machine.

PDF Basic

The Use Case: PDF print out of the JSON-driven dynamic webform submissions filled out by the end-user within your application.

PDF Plus

The Use Case: Forms are required to be on a pixel-perfect PDF background with a dynamic JSON form overlay on top of the PDF.

A PDF template designer that allows customization of the data and layout for PDF downloads generated from webform submissions made by the end-user

PDF-First forms can also be presented to the user as responsive web forms, but enable the ability to print the Submission to the pixel-perfect PDF background.

Contact sales@form.io for more information on the PDF Plus Server

Deploying the PDF Server in a Private Cloud or On-Premise Environment

Recommended CPU/memory config is 2 CPU cores and 4GB of memory.

A common deployment command for the PDF server looks as follows.

docker run -itd \
  -e "MONGO=mongodb://mongo:27017/formio" \
  -e "FORMIO_S3_SERVER=minio" \
  -e "FORMIO_S3_PORT=9000" \
  -e "FORMIO_S3_BUCKET=formio" \
  --network formio \
  --link formio-mongo:mongo \
  --link formio-minio:minio \
  --restart unless-stopped \
  --name pdf-server \
  -p 4005:4005 \

Which uses the following Environment Variables.

Environment Variables for Deployment

Required Environment Variables

The following environment variables are always required.

Environment VariableDescription


A Form.io license key


The connection string to your MongoDB-compliant database


The database secret. Although not technically required, it must match your Enterprise Server's DB_SECRET environment variable.

File Storage Environment Variables

The following environment variables involve the PDF Plus Server's file storage integration for storing PDF files. The PDF server currently supports minio, Amazon S3, and Azure Blob.

Environment VariableDescription


Minio hostname or IP address. Required when using minio. If set, the PDF Server will assume a minio configuration. If not set AND other FORMIO_S3_* variables are set (in particular, FORMIO_S3_REGION, FORMIO_S3_KEY, or FORMIO_S3_SECRET), the PDF Server will assume an AWS S3 configuration.


Minio port. Defaults to 9000.


S3 bucket name. Required when using minio or AWS S3.


AWS Access Key Id if using AWS S3, accessKey (the user-like id) if using minio. Required when using minio.


AWS Secret Access Key if using AWS S3, secretKey (the password-like id) if using minio. Required when using minio.


The connection string to your Azure Blob deployment. Required when using Azure Blob storage.


The Azure Blob container name. Required when using Azure Blob storage.

Optional Environment Variables

The following environment variables are optional.

Environment VariableDescription


Set this environment variable to communicate server-to-server with the PDF Server. The value for this environment variable passed as the x-admin-key header when sending server-to-server API calls to the PDF Server. See https://apidocs.form.io/#8e817291-38df-4338-889f-14cf38de5fbd for more information on how to use this header.


Mongo database name, if using localhost


File path to an SSL certificate authority file. This is usually a file with an extension of ".pem". For example, AWS DocumentDB may require this to be like the following value: "/src/certs/rds-combined-ca-bundle.pem"


Whether to enable using docker secrets.


The path to the docker secrets.


Boolean to indicate if the license key provided is an offline remote license key.


Determines how long (in milliseconds) the browser can run and execute before timing out. Default is 120000 milliseconds or 2 minutes.


Perform debugging within a PDF server. The following debug commands will do the following. This uses the Debug Module for Node.js so documentation can be found @ https://github.com/visionmedia/debug.

- DEBUG=*: Debug everything

- DEBUG=pdf.*: Debug all PDF related events

- DEBUG=pdf.create.*: Debug the PDF upload process

- DEBUG=pdf.get.*: Debug the PDF fetching process

- DEBUG=pdf.delete.*: Debug the PDF deleting process

- DEBUG=pdf.download.*: Debug the PDF submission download process.

Configure Portal for PDF Server

Now that you have the PDF server operational as well as the API Server, the next thing that needs to happen is to configure the Form.io Portal to use the correct DNS URL for the PDF Server URL. This is necessary because the "internal" DNS URL is used within the Enterprise Server configurations, and we now need to let the Portal know how to directly communicate with the PDF Server. To set this up, you will first need to navigate to your Project Settings and then click on PDF Server configuration page. Here you will then need to provide the Public DNS URL to the pdf server as follows.

The PDF Server URL field shown in Project Settings was deprecated in 8.0.1 and removed from the interface. It is now fully managed by the PDF_SERVER environment variable that is set on the API server.

Once you have done this, you should now be able to upload an existing PDF form, where it will then convert that PDF document into a Form.io webform overlay on top of that PDF form.

PDF Server Fine Tuning

This section covers some aspects of fine tuning a PDF server. If you want to speed up your deployment or you want to configure your deployment for large PDF handling, you might want to give a look at this section.

Mounting /tmp directory to RAM

If you have a virtual machine with large amount of RAM available, you can benefit from it by mounting container's /tmp directory to RAM. You can to this by adding --tmpfs /tmp:rw parameter to your docker run command. This will allow PDF Server to speed up IO processes by storing files in RAM instead of disk.

Configuring file cache time

File cache is a disk cache for HTML files used for PDF downloads. Default cache time is one hour. If you have a lot of PDF first forms with different PDFs in the background and you expect that all that forms will be printed to PDF very often, you might want to configure file cache time to eliminate disk memory limit reach. To do this you need to add FILE_CACHE_TIME environment variable to PDF Server config. The value should be number of milliseconds. The smaller cache time will result to less disk space usage and lower performance. The bigger cache time will result to more disk space usage and increased performance.

Configuring default viewer

If you prefer to use custom viewer rather that default viewer for PDF downloads, you can increase PDF download performance by adding PAGE_POOL_DEFAULT_VIEWER an environment variable to PDF server config. Its value should be the URL of your custom viewer.

Configuring timeouts

Here is the list of all configurable timeouts and their purposes:

Environment variableDescriptionDefault value


Used for PDF downloads. If you are printing large PDF files or your custom viewer has a lot of contents, you might want to increase this value.



Used for PDF downloads. If you are printing large submissions and/or large PDF files, consider increasing this value.



Primary timeout for html generation. It's used for PDF uploads. If you are going to upload large PDF files, consider increasing this value.



Backoff timeout for html generation. Its sum with primary timeout will be used for second try after postscript optimisation in case when first try failed. If you are going to upload large PDF files, consider increasing this value as well.


PDF Server Plus Auto-Conversion

The PDF Server Plus includes Auto-Conversion of existing fillable and non-fillable PDF Forms. Using AWS Textract for PDF First Forms that do not have any metadata that can be read for conversion, the PDF Server will auto-detect Field Input Types, Labels and more and convert the PDF to a dynamic Form.io Form!

AWS Textract Integration

Please note that the Textract feature is exclusively compatible with AWS S3 bucket storage infrastructure. Unfortunately, it is NOT compatible with Minio or other object storage providers. It is imperative to utilize AWS S3 for object storage in order to leverage the functionalities of Textract effectively.

After setting up PDF Server it is possible to integrate with AWS Textract to enable Formfields Recognition feature.

Steps to integrate:

  1. Create IAM role with AmazonTextractServiceRole & AmazonSNSFullAccess policies

    • Create a Custom trust policy with the following JSON structure.

        "Version": "2012-10-17",
        "Statement": [
                "Sid": "",
                "Effect": "Allow",
                "Principal": {
                    "Service": "textract.amazonaws.com"
                "Action": "sts:AssumeRole"
    • Next add your AmazonTextractServiceRole & AmazonSNSFullAccess permissions.

    • Add a Role name and then press Create Role in the bottom right corner.

  2. Verify that the AWS User has permissions for textract:StartDocumentAnalysis & textract:GetDocumentAnalysis

    • This can be done with a similar inline policy like outlined above but for the security credentials belonging the security credentials being utilized.

    "Version": "2012-10-17",
    "Statement": [
            "Effect": "Allow",
            "Action": [
            "Resource": "*"
  1. Create AWS Simple Notification Service topic and save its ARN

  2. Add the following environment variables to the configuration:

VariableDescriptionDefault value


Name of the S3 bucket where files are stored



AWS public access key



AWS secret access key



AWS bucket region



ARN of IAM role for Textract.



ARN of SNS topic.



S3 bucket folder where Textract will store its output.



Allows for configure the timeout for Textract processing to finish. Increase for larger non-fillable documents. (Optional)


4. After starting the PDF environment with new environment variables, go to the previously created SNS topic page and create a subscription:

  • Leave Topic ARN as-is

  • In Protocol field choose HTTPS

  • In Endpoint field type *public URL of your environment. Example: https://my.formioapi.com/pdf/pdf/sns

  1. After configuration you can check the status of formfields recognition by visiting URL {{apiServerUrl}}/pdf/pdf/sns/recognizeFormfieldsStatus

  1. Validate that PDF Plus upload works with a Non-fillable PDF and has Textract perform field recognition on the non-fillable pdf form. An example non-fillable pdf form has been provided below.

In the case of misconfiguration, you will not be able to upload a PDF file.

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