axesPDF vs Nutrient DWS Accessibility API

axesPDF has no write-up on Specifiction yet; its figures are above.

Nutrient DWS Accessibility API processes PDFs to add accessibility tags and check conformance. It returns a tagged PDF with PDF/UA metadata and targets PDF/UA-1 (ISO 14289-1). Tagging covers H1–H6 headings, ordered and unordered lists, table rows and cells, reading order, annotations and decorative artifacts. The API accepts HTTP requests from any programming language, with quickstarts for Java, C#, JavaScript, Python and PHP. Nutrient reports 96.5% PDF/UA conformance across a validation corpus of 3,157 files. Its free plan costs nothing and includes 20 auto-tagged pages and 100 validations per month. Starter costs $79 a month for 200 pages and 1,000 validations; Professional is $249 a month for 1,000 pages and 5,000 validations; Business is $499 a month for 3,000 pages and 15,000 validations. Monthly quotas do not roll over, and requests in a quota category are blocked when that quota runs out unless a larger plan or pay-as-you-go is used. Auto-tagging does not guarantee full accessibility compliance, so Nutrient recommends QA, especially for sensitive or high-stakes documents.