Here are seven criteria to consider adding to your evaluation checklist:
1. Fast Performance
A HTML5 document viewer should provide features such as PDF linearization, parallelization between server and client, and client-side document manipulations that greatly improve performance using minimal data bandwidth. Linearization of documents is critical for users who are trying to view large, multipage documents when using slower bandwidths or remotely from their mobile devices.
Without these features, you can encounter behavior such as slow rendering high server memory consumption, network data transfer issues, and most of all, your users waiting for documents to render after each operation such as scrolling and panning across, and zooming into content.
Test the document viewers at an appropriate usage, common document sizes, and server load. Some solutions perform excellently when tried on a small number of documents and users but impose unexpected hidden costs when later scaled up.
2. Reliably Opens Documents
Certain documents are also intrinsically memory-intensive or corrupted, failing to open or otherwise crashing some viewers.
And for your end users, a single document that fails to open at the 11th hour before they launch or go into production could mean the difference between their success or failure. Users may quickly abandon your app for third-party workarounds if it is seen as unreliable.
Many people don’t realize the frequency of corrupted documents. And the reason other viewers are able to show corrupted content is because they repair it on the fly. If a document is viewable in other readers, users will expect it to be viewable in newer software.
When you test an HTML5 document viewer, use a large body of documents that capture the variety of what your users will expect to open, and include their most demanding documents, such as documents with very large file sizes (1GB+), complex graphics, or many pages (e.g., 1,000+).
3. Accurate Rendering
It is also important to bear in mind that some of the most common file types are incredibly complex. The file may have many fonts, embedded formats, overlays, languages, and graphics. As a result, not all HTML5 document viewer will render various files the same way.
Don’t take a vendor’s claims that their viewer is mature and battle-tested at face value. Test the rendering yourself to evaluate whether your documents will render as expected.
4. Customizable UI
Optimizing the UX and streamlining the UI is critical to ensure end-user adoption and a factor in determining the success or failure of an application.
The ability and/or flexibility to modify the UI provides a high degree of freedom to provide the experience your users need. It also may be crucial if you have very strict or specific UI requirements. Also the ability to restrict access to certain features to all or a subset of your users.
Make sure your vendor is able to assist with any UX and UI changes that may be necessary either to be hardcoded, modified CSS code on your end, or through an admin configuration webpage.
5. Future Proof
Next, end-user needs will likely evolve to include a need for more functionality, file formats, or platforms.
A feature-rich, cross-platform HTML5 document viewer including client-side and server-side functionality saves you from having to consider purchasing other viewers for other applications. Instead, all the functionality you would ever need is already available through a single partner that can enable seamless, long-term growth. Also making sure developers are constantly adding more APIs and supporting existing APIs is critical for long-term use in your application.
6. Fully Supporting Required Document Types
With a format as complex as PDF, MS Office, and MOD:CA, you are also likely to need an experienced vendor capable of dealing with new edge cases and undocumented format behaviors as they emerge.
If the vendor is wraps an open-source libraries, they may not have the expertise to respond as decisively as a commercial vendor who built and therefore, understands their rendering engine from the ground up. Also, they will not be able to resolve issues that when a document doesn’t render correctly in the viewer.
Vendors with in-house development and support of their rendering engines will have the ability to quickly resolve rendering issues as they arise.
7. High Priority Support
A final consideration is whether the company providing the viewer will provide the level of support your company needs and deserves.
Many times this aspect is overlooked whereas is should be taken into high consideration. Is the company you are going to be buying from, going to stand by their product when you need assistance? How much efforts will the focus on getting you back up and running? Do you have access to talking to engineers over a web meeting or do you have to go through a call center representative to get all your assistance from? Will you have to wait for semi-annual updates to get any fixes or do you get a hotfix in the interim?
These are all important questions to ask a prospective vendor before signing an agreement to purchase and form a “partnership” with.