Software Alternatives, Accelerators & Startups

DocSpring VS RepDB

Compare DocSpring VS RepDB and see what are their differences

DocSpring logo DocSpring

PDF filling API that makes it easy to fill out PDF forms and convert HTML to PDFs

RepDB logo RepDB

Exercise dataset for fitness apps: transparent background, animations, no subscription
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  • DocSpring PDF Template Editor
    PDF Template Editor //
    2025-02-26
  • DocSpring HTML Template Preview
    HTML Template Preview //
    2025-02-26
  • DocSpring HTML Template Editor
    HTML Template Editor //
    2025-02-26
  • DocSpring Auto-generated Web Form
    Auto-generated Web Form //
    2025-02-26
  • DocSpring E-Signatures
    E-Signatures //
    2025-02-26
  • DocSpring View Submissions
    View Submissions //
    2025-02-26
  • DocSpring View API Request Logs
    View API Request Logs //
    2025-02-26
  • DocSpring Postman Collection
    Postman Collection //
    2025-02-26

We provide a PDF filling and generation API:

  • Upload your PDF to our visual template editor to set up form fields and data types
  • Post JSON to fill out existing PDF forms with data
  • Generate editable PDF forms, or overlay static data on top of fields
  • Create HTML/CSS templates with Liquid fields, then post JSON to generate PDFs
  • Use our merge API to combine multiple PDFs into a single document

PDF generation doesn't need to be complicated or take weeks of engineering time. Use our battle-tested service to start filling out PDFs in minutes.

  • RepDB
    Image date //
    2026-07-21
  • RepDB Landing page
    Landing page //
    2026-07-21
  • RepDB
    Image date //
    2026-07-21

RepDB is a one-time-purchase exercise dataset for developers building fitness and workout apps โ€” not a subscription, not a rate-limited API. You download the data once and own it: JSON (and SQLite on the higher tier), WebP images, and full EN/DE/ES translations, with no per-request billing and no dependency on our servers staying up.

A free tier includes 400 exercises with flat-style 512ร—512 images, attribution-licensed for commercial in-app use. The Starter tier ($199) adds the full catalog in classic white-background style. Standard ($399) adds transparent 1024px images, looping animations, exercise relations (similar/progressions/regressions), workout templates, and embeddings โ€” exclusive to that tier.

Every exercise includes muscle-group highlighting, equipment/muscle icons, MET values, and safety/goal tags. Compared to GIF- or JPG-based competitor APIs, RepDB images are transparent WebP with no watermarks, so they drop into any app UI without a white box around them.

DocSpring

$ Details
freemium $49.0 / Monthly (Starter - 50 PDFs / mo)
Platforms
-
Release Date
2017 October
Startup details
Country
United States
State
Delaware
City
Newark
Founder(s)
Nathan Broadbent
Employees
1 - 9

RepDB

Website
repdb.co
$ Details
freemium $199.0 / One-off
Platforms
Web Mobile
Release Date
2026 July

DocSpring features and specs

  • Automated PDF Generation
    DocSpring allows users to automate the generation of PDFs by filling out templates with data. This can significantly reduce the time and effort needed to create documents.
  • API Integration
    DocSpring offers a robust API, which allows developers to integrate PDF generation into their own applications easily, enhancing productivity and workflow automation.
  • Flexible Templates
    The platform supports flexible and customizable templates, enabling businesses to maintain brand consistency while meeting specific document formatting requirements.
  • Secure Data Handling
    DocSpring is SOC 2 Type II compliant. We ensure data security through encryption and secure storage options, making it suitable for handling sensitive information.
  • Ease of Use
    The user interface is designed to be intuitive, making it easy for businesses to create and manage PDF templates without requiring extensive technical knowledge.

RepDB features and specs

  • WebP Format Benefits
    start+peak exercise images
  • JSON
    relations, metadata, equipment
  • Transparency
    transparent background
  • Animations
    Animated loops in paid tier

Category Popularity

0-100% (relative to DocSpring and RepDB)
PDF Tools
100 100%
0% 0
Datasets
0 0%
100% 100
Document Automation
100 100%
0% 0
Developer Tools
0 0%
100% 100

Questions & Answers

As answered by people managing DocSpring and RepDB.

Which are the primary technologies used for building your product?

DocSpring's answer

Ruby on Rails, React, AWS

What makes your product unique?

DocSpring's answer

DocSpring is built specifically for developers who need reliable, secure PDF generation in production. We combine PDF form filling and HTML-to-PDF in a single API, with a visual template editor, typed fields, and validation to catch issues early. Our product has a lot of power features and is built to handle very advanced forms. Our infrastructure is SOC 2 Type II compliant, battle-tested, privacy focused, and optimized for high-volume workloads, so you can ship PDF features quickly and then stop thinking about them.

RepDB's answer:

RepDB is sold as a one-time download, not a metered API โ€” you own the JSON/SQLite data and WebP images outright, with no rate limits, no per-request billing, and no risk of the vendor cutting off access. It's also the only dataset in this space with EN/DE/ES translations, transparent (alpha-channel) images with no watermark, muscle-group highlighting, safety/goal tags, and looping animations on the higher tier.

Why should a person choose your product over its competitors?

DocSpring's answer

DocSpring is designed for teams who need a powerful tool with all the features you need for complex forms and business logic. DocSpring supports structured JSON, typed fields, and array iterations, and many other advanced features, so your templates stay aligned with your real data model. You get powerful validation, a visual editor, strong observability, and an API that fits into modern engineering workflows, so you spend less time fighting PDFs and more time shipping product.

RepDB's answer:

Most alternatives are subscription APIs โ€” you pay monthly, you're capped on requests, and ExerciseDB's terms of use explicitly forbid caching or storing the data at all, so every image render is a live paid API call. RepDB is the opposite: pay once, download the files, self-host with zero ongoing dependency. It's also the only option offering true DE/ES localization and transparent images instead of a white box behind every exercise.

How would you describe the primary audience of your product?

DocSpring's answer

DocSpring is built for engineering and product teams who manage complex documents in production: things like financial applications, insurance forms, healthcare and legal documents, HR and payroll workflows, and government-style forms.

RepDB's answer:

Solo developers and small teams building fitness or workout-tracking apps (iOS, Android, web) who need licensed exercise images and structured exercise data, but don't want to build their own media pipeline or depend on a rate-limited third-party API.

What's the story behind your product?

DocSpring's answer

I used to work at a payroll company (Gusto). We had built a similar in-house tool for filling out tax forms. I then built the first version of DocSpring (formerly named FormAPI) while I was living in Thailand. I built it to automate the filling out of visa application and visa extension forms, but realized that it could also be used for tax forms, real estate contracts, and any other kind of fillable PDF form.

RepDB's answer:

RepDB grew out of a consumer workout app its creator was building solo. Sourcing exercise images and data meant either paying for a subscription API with usage caps and no caching rights, or producing everything from scratch. The illustrated, multi-language dataset was built for us first, then split out as its own product once it became clear other indie developers had the same problem and preferred to buy the data outright rather than rent it through an API.

Who are some of the biggest customers of your product?

DocSpring's answer

  • SaaS services serving customers in the real estate, insurance, finance, and legal industries, among many others.

User comments

Share your experience with using DocSpring and RepDB. For example, how are they different and which one is better?
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Social recommendations and mentions

Based on our record, DocSpring seems to be more popular. It has been mentiond 5 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.

DocSpring mentions (5)

  • Ask HN: What Are You Working On? (February 2025)
    I'm still working on DocSpring [1], originally launched on Hacker News in October 2017 under the name "FormAPI." It's a PDF generation API with a template editor UI for setting up fields on PDF forms. It makes it easy to turn complex tax and immigration forms into simple type-safe APIs with strong validations. I've been having a lot of fun with AI agents lately. Have tried a lot of them - Cline, Roo Code,... - Source: Hacker News / over 1 year ago
  • Launch HN: Onedoc (YC W24) โ€“ A better way to create PDFs
    For programmatic filling of PDFs, have a look at DocSpring: https://docspring.com. - Source: Hacker News / over 2 years ago
  • So you want to modify the text of a PDF by hand
    Great post. I've spend a lot of time reading through the PDF specification over the last ~5 years while building DocSpring [1], and I still feel like I've barely scratched the surface. Qpdf is a great tool. One of my other favorites is RUPS [2], which really lets you dig into the structure of a PDF. [1] https://docspring.com [2] https://github.com/itext/i7j-rups. - Source: Hacker News / almost 3 years ago
  • Workflow for automating document creation from a "database"
    Hi /u/pepeday, Iโ€™m the founder of a software product that I built to solve this problem. The service is called DocSpring: https://docspring.com We provide a platform that you can use to set up PDF templates, and automatically generate PDFs by filling in those templates with data from your database. Please feel free to send me a message and Iโ€™d be happy to speak with you and help you figure out a solution. I can... Source: almost 5 years ago
  • How do you fill copies of the same PDF certificates with Excel data?
    - https://docspring.com/ (super advanced features, a bit bloated). Source: almost 5 years ago

RepDB mentions (0)

We have not tracked any mentions of RepDB yet. Tracking of RepDB recommendations started around Jul 2026.

What are some alternatives?

When comparing DocSpring and RepDB, you can also consider the following products

DocRaptor - As the only API powered by the Prince HTML-to-PDF engine, DocRaptor provides the best support for complex PDFs with powerful support for headers, page breaks, page numbers, flexbox, watermarks, accessible PDFs, and much more

Doczilla - Effortlessly create stunning PDFs and screenshots. Seamlessly store them in your own AWS or Google Cloud Storage bucket, putting the control and creativity right at your fingertips.

wkhtmltopdf - wkhtmltopdf is an open source (LGPL) command line tools to render HTML into PDF and various image...

PDF Generator API - Generate PDF documents from templates and JSON data. Enable your users to create PDFs and manage document templates using a browser-based drag-and-drop editor!

DocuSign - Try DocuSign's interactive signing demo now! Send yourself an electronic document to digitally sign using our e-signature service.

MailMergic - Effortless Mail Merge for PDFs โ€” Generate, personalize, and send documents in minutes, not hours.