pdftt
Example
node bin/pdftt.js template.pdf output.pdf \ '[{"page":0, "x":100, "y":200, "size":20, "text":"this is test"}]'
Docker build
docker build . -t ngyuki/pdfttdocker run --rm -i ngyuki/pdftt \ pdftt - - '[{"page":0, "x":100, "y":200, "size":20, "text":"あいうえお"}]' \ < template.pdf > output.pdf