Exploring the Top Document Conversion APIs

When it comes to document conversion APIs, there are different options out there: In this post, we will compare some of the top APIs that we tried.
Exploring the Top Document Conversion APIs
Sohail Pathan
Last updated on October 04, 2023


As a developer, you have likely experienced the need to convert and deliver docs to others in your apps — and though there are a variety of file types, chances are your app has required conversion from an MS Word doc or PDF.

What are Document Conversion APIs?

These are APIs that can take a source input file in the form of docx, doc or PDF and convert them to PDF. As we have discussed before, converting to PDF has multiple pros, including consistent formatting, security and reduced file size.
In this blog post, we will talk about some of the available solutions out there: We’ll discuss the features, functionality, and benefits of each API which can help developers choose what suits them best based on their specific project requirements.

Features & Functionality:

Input Methods
ApyHub allows you to provide source input files in both Binary and Base64 formats. CloudConvert, ConvertAPI, and CloudMersive take input as Remote URLs and Binary Files.
SDKs and Client Libraries
ApyHub provides the client code <in 8 languages (C, C#, JavaScript, Go, NodeJS, Java, Python, and PHP) and SDKs in Node.js and Go. CloudConvert provides SDKs in about 7 different languages, including PHP, Node.js, Python, Ruby, Java, and .NET. ConvertAPI currently offers the client code 7 programming languages, including Go, Python, Ruby, Java, C#, PHP, and JavaScript, but no SDKs. Cloudmersive supports 8 programming languages, including Go, Python, Ruby, Java, C#, PHP, JavaScript, and Swift.
Client Code Generator: ApyHub and ConvertAPI
Apyhub APIs include thorough documentation, including the Authentication method, Error Codes, HTTP Response Codes, and Request Examples. Cloud Convert also has rich language-specific documentation but does not include Error & Response codes, whereas CloudMersive also has great language-specific documentation including some examples.
API Testing
Most of the providers let you test the APIs right from a terminal in the platform. ApyHub also has an API Playground where you can test the APIs in the UI plus you can see the snippet of the provided input in cURL.
ApyHub’s API Playground
ApyHub has served *99.9% of uptime. Convertapi, CloudConvert, and Cloudmersive also claim to have high uptime.
Integration with No Code Tools
CloudConvert provides integration support as a connector or extension of tools like Zapier, Microsoft, Make, and n8n. ApyHub has developed specific guidelines and tutorials for using APIs inside no/low code platforms, including Retool, Softr DronaHQ, and others. Cloudmersive and ConvertAPI do not appear to mention anything about connecting with low code platforms.
This is subject to change but at the time of writing, all providers offer a subscription based tiered model including a free plan. The most generous free plan is from ApyHub, offering 20 Million! API calls per month for free, whereas Cloudmersive offers 800 calls per month, Covert API offers only 250 calls. Finally, CloudCovert offers 25 calls per day, so 750 calls per month.
Community Support
Most of the providers offer dedicated channels such as Discord, Slack, or Chatbot Agent to their users to ask support questions. ApyHub has its own Discord Server, which lets you interact directly with the support team. CloudConvert has email-based support, whereas ConvertAPI and Cloudmersive provide chat-based support.
Below is a summary of the comparison of the providers I looked at. We focused on:
  • #API calls
  • Inputs
  • File size
  • Pricing
  • Throttling
  • Storage
Provider# Calls (Free)InputsFile SizePricing ( Paid )ThrottlingStorage
ApyHub2M calls in the free planBASE64, PPT, PPTX, DocX, ODF, PNG, JPEG, XLS, XLSX, HTML OR File URL50 MBStarting from 10 EUR/month. Custom pricing plan for Enterprises.1 call/s in the free planYes, 2 GB
CloudConvert25 calls Per DayDOCX, DOC, PPTX, PPT, XLS, XLSX1 GBStarting from 8.5 EUR/month1 call/in the free planNo
ConvertAPI250 callsDOCX, PPTX, XLSX, PNG, JPG, SVG, EPUB, OR File URL200 MBStarting from 76 EUR/month.1 call/in the free planNo
Cloudmersive800 calls/monthDOCX, DOC, PPTX, PPT, XLS, XLSX OR File URL3.5 MBStarting from 18 EUR/month.1 call/in the free planNo


When it comes to document-to-PDF conversion APIs, ApyHub, CloudConvert, ConvertAPI, and Cloudmersive all provide unique features and benefits for developers. Depending on the specific project requirements, developers can choose the API that best suits their needs.
With factors such as supported file formats, conversion accuracy, integration simplicity, and additional functionalities, developers can make a decision and leverage the most useful API to streamline their document conversion workflows.
Do you agree with our list of the above API Providers? What do you think is the best PDF API? Let us know your thoughts in the comments below.