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Documentation Index

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The POST /print endpoint returns one of three HTTP response types. A 200 OK is returned when PDF generation succeeds, delivering the binary PDF directly in the response body. A 400 Bad Request is returned when the request is malformed — most commonly because the required html field is absent. A 500 Internal Server Error is returned when Puppeteer or headless Chromium encounters an unexpected failure during rendering. Both error responses share the same JSON envelope shape, making client-side error handling straightforward.

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200 — Success

When PDF generation succeeds, the API returns the binary PDF file directly in the response body.
  • Content-Type: application/pdf
  • Body: Raw binary PDF data
The following example uses curl to send a minimal request and save the returned PDF to disk: 
curl 'https://{api-identifier}.execute-api.us-east-1.amazonaws.com/prod/print' \
  -X POST \
  -H 'Content-Type: application/json' \
  -d '{"html":"<html><body>Hello</body></html>"}' \
  --output result.pdf
For very large PDFs, the response may take one of two alternate forms depending on the generated file size:
  • Gzip-compressed — The response body is compressed and includes a Content-Encoding: gzip header. Most HTTP clients and libraries decompress this automatically.
  • S3 redirect — The response is an HTTP 303 See Other with a Location header pointing to a pre-signed Amazon S3 URL where the PDF can be downloaded. Most HTTP clients follow this redirect automatically.
See Large Response Handling below for more detail.

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400 — Bad Request

A 400 response is returned when the request body fails validation. The most common cause is omitting the required html field.
  • Content-Type: application/json
  • Error code: PRINT_FAILED_HTML_MISSING
The response body is a JSON array. Each element in the array represents one failure and contains a value object with a machine-readable code and a human-readable message, plus a children array for nested failure details.
​
[].value
object
Top-level failure descriptor for this error item.
​
[].children
array
An array of nested failure objects. Empty for top-level validation errors.
Example response: 
[
  {
    "value": {
      "code": "PRINT_FAILED_HTML_MISSING",
      "message": "Failed to print PDF, no HTML document provided."
    },
    "children": []
  }
]

​
500 — Internal Server Error

A 500 response is returned when Puppeteer or headless Chromium encounters an error during PDF generation. This may be caused by a malformed HTML document that triggers a renderer crash, an unhandled exception in the Lambda handler, or an infrastructure-level problem.
  • Content-Type: application/json
  • Error code: REQUEST_GENERAL_FAILURE
The response body follows the same JSON array envelope as the 400 response. Example response: 
[
  {
    "value": {
      "code": "REQUEST_GENERAL_FAILURE",
      "message": "An attempt to print html page failed for unspecified reason(s)."
    },
    "children": []
  }
]
When a 500 error occurs, the Lambda function logs the full stack trace to Amazon CloudWatch Logs. Navigate to the Log groups section of the CloudWatch console, find the log group for your Lambda function (typically /aws/lambda/{function-name}), and inspect the most recent log stream to identify the root cause.

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Large Response Handling

AWS Lambda and API Gateway impose payload size limits that can be exceeded by large generated PDFs. The service handles this transparently using two strategies: Gzip compression — If the PDF can be reduced to an acceptable size through compression, the response is returned inline with a Content-Encoding: gzip header. Verify your HTTP client is configured to decompress gzip responses (most are by default). S3 pre-signed URL redirect — If the compressed PDF still exceeds the payload limit, the service uploads the file to Amazon S3 and returns an HTTP 303 See Other response. The Location header contains a time-limited pre-signed S3 URL from which the PDF can be retrieved. Most HTTP clients (including curl with -L and browser fetch) follow 303 redirects automatically. For deeper background on these two strategies and how to configure them, see Large Responses.

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