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DocSpring Blog

What we've learned building DocSpring: Ruby on Rails, PDFs, testing, infrastructure, and developer tools.

  2. A cut ruby gemstone fitted exactly inside a navy blueprint outline, connected to four code cards with teal check marks, above a tag reading typed: strict.

    14 min read

    Going all-in on Sorbet

    Sorbet sat in our Rails app for 18 months with a tenth of the code typed. Then AI agents typed the rest in four days, and we kept going.

  3. An SDK card and an API card, each connected by a line to a filled PDF form

    4 min read

    PDF form filler SDK vs API

    When a PDF library is enough to fill your forms, and when a hosted API saves you the work.

  4. A JSON data card connected by a line to a PDF form with filled fields, a ticked checkbox and a signature

    5 min read

    Best PDF form filling APIs (2026)

    DocSpring, Anvil, PDF.co, Adobe PDF Services, and Nutrient compared for filling fillable PDFs and flat PDFs.

  9. Request and job logs converge into a structured JSON event.

    6 min read

    LogStruct: Structured Logging for Rails

    Request logs are only part of a Rails application's output. LogStruct brings JSON logging, sensitive-data filtering, and typed events to jobs, mailers, and the rest of your app.

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