Amazon Textract vs Google Cloud Document AI

Amazon Textract

IAM policies limit a credential to single operations, CloudTrail logs every call, and page prices start at $1.50 per 1,000 in US East. Multipage files need S3 and an asynchronous job. Text detection covers six languages. Under the AWS Service Terms AWS may store and use documents to improve the service unless an AI services opt-out policy is set.

Google Cloud Document AI

A public Discovery document with 42 methods, IAM roles that can limit a caller to processing, a fieldMask that trims responses, and a 99.9 per cent SLA on the US and EU endpoints. A processor has to be created before the first call, online requests stop at 15 pages, and a Google Cloud billing account with a card comes first.

Amazon Textract

1. Sign with SigV4 for service textract at textract.<region>.amazonaws.com, or call aws textract detect-document-text. The AWS CLI can't send image bytes, so reference an S3 object
2. Use StartDocumentTextDetection or StartDocumentAnalysis for any PDF or TIFF of more than one page, pass a ClientRequestToken, then page Get calls with NextToken (1,000 blocks at most each)
3. Fetch results within 7 days of starting a job, or set OutputConfig to write them to your own S3 bucket
4. Request only the FeatureTypes you need. Forms cost $50 per 1,000 pages against $15 for tables or queries in US East
5. Back off on ProvisionedThroughputExceededException (HTTP 400) and ThrottlingException (HTTP 500). Neither carries Retry-After, and default quotas are 1 call a second in most Regions
6. Set the AI services opt-out policy on the AWS organisation before sending customer documents

Google Cloud Document AI

1. Create a processor first (processors.create or the console), then POST to https://LOCATION-documentai.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/processors/PROCESSOR_ID:process
2. Use the host that matches the processor's location, us-documentai.googleapis.com or eu-documentai.googleapis.com
3. Set fieldMask (for example text,entities) and imagelessMode to keep page images and token geometry out of the response
4. Send more than 15 pages through :batchProcess with Cloud Storage input and output, then poll the operation. Jobs unfinished after 24 hours are cancelled
5. Grant the service account roles/documentai.apiUser only. Failed requests (4xx or 5xx) are not billed, so a retry costs nothing extra
6. Treat extracted text as untrusted input