{"title":"Enketo Blog","link":[{"@attributes":{"type":"application\/atom+xml","href":"https:\/\/blog.enketo.org\/feed\/index.xml","rel":"self"}},{"@attributes":{"href":"https:\/\/blog.enketo.org"}}],"updated":"2025-07-09T15:49:56+00:00","id":"https:\/\/blog.enketo.org\/","author":{"name":"Martijn van de Rijdt"},"rights":"Copyright (c) 2010-2013 Martijn van de Rijdt","entry":[{"title":"Kobo is now maintaining Enketo","link":{"@attributes":{"rel":"alternate","href":"https:\/\/blog.enketo.org\/kobotoolbox-enketo\/"}},"updated":"2025-03-17T00:00:00+00:00","id":"https:\/\/blog.enketo.org\/kobotoolbox-enketo\/","content":"

We\u2019re excited to share that the KoboToolbox team has officially taken over the maintenance and development of Enketo<\/strong>.<\/p>\n\n

Enketo started in 2009 as a web-based alternative to ODK Collect, and over the years it has become a key part of various data collection platforms including ODK<\/a> and, of course, KoboToolbox<\/a>. Every day, hundreds of thousands are collecting data through Enketo web forms in KoboToolbox, and we look forward to investing more to make this indispensable tool even better by directly taking responsibility of its future.<\/p>\n\n

At KoboToolbox, we\u2019ve relied on Enketo for many years to provide our users with a flexible, browser-based form-filling experience that works both online and offline. We invested a lot in the early days of the platform as an independent platform for webform-based data collection together with its original creator, Martijn van de Rijdt. This included creating Enketo Express to allow fully offline data collection, adding many advanced features that users demanded from the availability on the Collect Android app, and open-sourcing all components of Enketo for wider distribution. Now, we\u2019re proud to be taking on this great project\u2019s future development and ensuring its continued availability as a vital open-source tool for humanitarian, development, and research work worldwide.<\/p>\n\n

We\u2019re deeply grateful for the incredible work that Martijn has done over the past decade in creating and leading Enketo, and for the stewardship of the ODK team in recent years that has made the Enketo codebase better, faster, and easier to maintain. We look forward to building on this foundation\u2014continuing to improve performance, security, and compatibility, while also exploring new opportunities to extend Enketo\u2019s capabilities to meet the evolving needs. This will include native audio recording, easier theming, improved user experience for complex form navigation, and much more.<\/p>\n\n

We welcome suggestions, contributions, and collaboration proposals! Please post your suggestions on the KoboToolbox community forum<\/a>, we look forward to building this next chapter with all the loyal Enketo users around the world.<\/p>\n\n

Many thanks again to everyone who has contributed to Enketo over the years \u2014 you\u2019ve made this an indispensable tool for so many.<\/p>\n"},{"title":"Enketo has joined ODK!","link":{"@attributes":{"rel":"alternate","href":"https:\/\/blog.enketo.org\/enketo-has-joined-odk\/"}},"updated":"2023-05-14T00:00:00+00:00","id":"https:\/\/blog.enketo.org\/enketo-has-joined-odk\/","content":"

I started Enketo in 2009 as a web-based alternative to ODK Collect<\/a>, the popular Android app for offline data collection. Over time, Enketo has grown into a core component of great products like Ona<\/a>, KoboToolbox<\/a>, OpenClinica<\/a>, Survey123<\/a>, and of course, ODK<\/a>.<\/p>\n\n

Though I have had a great time developing Enketo and collaborating with so many impressive people, the past few years I have become increasingly interested in working on other things (such as woodworking). In August 2021, the ODK team agreed to take over leadership of the Enketo project. My own involvement in the greater Enketo project has reduced to just a few hours a week, and that work is mostly on custom features for a client.<\/p>\n\n

One and a half years after handing over control, it is clear that Enketo is in excellent hands! ODK (especially Yaw Anokwa<\/a>, H\u00e9l\u00e8ne Martin<\/a>, and Trevor Schmidt<\/a>) have been doing an awesome job adding performance improvements, aligning behavior with ODK Collect, fixing critical vulnerabilities, and many other things. I am very impressed with their thoughtful approach to development (and am learning from it) and their willingness and ability to make big investments in improving the code, toolchain, and maintainability. I am so happy that Enketo is continuing to thrive and am excited about its future.<\/p>\n\n

Many thanks to ODK and all of Enketo\u2019s contributors over the years!<\/p>\n\n

P.S. If you haven\u2019t used ODK recently, you\u2019re missing out! Request a demo at getodk.org<\/a> to learn more.<\/p>\n"},{"title":"Huge leap in performance","link":{"@attributes":{"rel":"alternate","href":"https:\/\/blog.enketo.org\/performance-leap\/"}},"updated":"2021-02-04T00:00:00+00:00","id":"https:\/\/blog.enketo.org\/performance-leap\/","content":"

A new XPath evaluator<\/h3>\n\n

We have just completed the most exciting, and largest, Enketo improvement project in years - a new XPath evaluator<\/a>! If you are not familiar with XPath, it is the logic language<\/em> of forms in the ODK ecosystem which is used in calculation<\/em>, constraint<\/em>, relevant<\/em>, required<\/em>, choice_filter<\/em>, and default<\/em> formulas.<\/p>\n\n

Back when Medic adopted Enketo<\/a> in their mobile data collection tools for Community Health Workers, they created a new XPath evaluator to replace the one Enketo was using. This new evaluator turned out to be much faster as it more fully leveraged the native XPath evaluator that is built into modern browsers.<\/p>\n\n

At the time it was created, it did not yet have all the capabilities that the Enketo Project needed to replace its own XPath evaluator. Moreover, the need to support legacy browsers (without a native evaluator) was still holding us back. However, we started planning a long time ago to make Medic\u2019s evaluator fully ODK XForms<\/a> spec-compliant and have since dropped support for legacy browsers<\/a>.<\/p>\n\n

With funding from DIAL<\/a>, OpenClinica<\/a>, and Medic<\/a>, and the wizard-level coding skills of Alex Anderson<\/a> (who started the initial project for Medic Mobile, and agreed to temporarily join Enketo LLC help finish it using OpenClinica funding), this XPath library is now fully ready to take over logic evaluation across all Enketo tools!<\/p>\n\n

Enketo Express version 2.6.0<\/strong> and Enketo Core version 5.17.0 onwards include the new evaluator.<\/p>\n\n

And WOW<\/strong>, the boost in performance has exceeded all expectations! We have evaluated the impact on some extremely slow real-life forms and shared some results below. I should note it is not entirely straightforward to predict the impact for a particular form. We have found (fast) forms that had no noticeable change in loading performance. We have not found any forms that have become slower.<\/p>\n\n

Large internal lists of options<\/h4>\n\n

A form containing thousands of \u201cselect\u201d options (found here<\/a>) took over 5 minutes to load with the old evaluator. It now takes 0.4 seconds. A 750x<\/strong> improvement making a previously unusable form perfectly usable! Forms with large \u2018internal\u2019 select lists definitely experienced the largest performance improvement (forms with \u2018external\u2019 lists were already fast).<\/p>\n\n

Large number of repeat instances<\/h4>\n\n

A form containing 45 repeat instances (with repeat_count) from an OpenClinica user, improved its loading performance from 25 seconds to 6.5 seconds - a respectable 4x<\/strong> improvement.<\/p>\n\n

Complex constraint expressions<\/h4>\n\n

A form with about 1,000 questions with an enormous quantity of complex constraints from an OpenClinica user improved its loading performance from 7.5 seconds to 0.3 seconds - a 25x<\/strong> improvement!<\/p>\n\n

Thanks<\/h3>\n\n

Thanks so much to Medic<\/a>, DIAL<\/a>, OpenClinica<\/a> and Alex<\/a> for making this epic improvement project possible!<\/p>\n\n

Feedback<\/h3>\n\n

As always, we\u2019d love to get your feedback. Comment on this blog, tweet @enketo<\/a>, or post a message in the Enketo forum<\/a>. If you discover a bug, please let us know what browser you are using.<\/p>\n\n"},{"title":"Important Enketo Express Updates - 03\/2020","link":{"@attributes":{"rel":"alternate","href":"https:\/\/blog.enketo.org\/Enketo-Express-mar-2020-update\/"}},"updated":"2020-03-30T00:00:00+00:00","id":"https:\/\/blog.enketo.org\/Enketo-Express-mar-2020-update\/","content":"

This post is meant for people that are running their own Enketo Express installation and particularly those that use Enketo\u2019s offline-capable webforms.<\/p>\n\n

A BIG change<\/h3>\n\n

Chrome version 83<\/del> 85 (expected in May<\/del> August 2020) will no longer support a caching technology<\/a> Enketo has been using since 2012 to launch offline.<\/p>\n\n

Thankfully, there is a better technology available that is widely supported across all modern browsers and Enketo Express has switched to this technology in version 2.0.0 in March 2020. Users will have to refresh one of the offline-capable webforms they are using to switch to this new type of cache once this version has been deployed by you. The new webform URLs will also be slightly different but old URLs will be redirected automatically.<\/p>\n\n

It is recommended to take 2 steps to best deal with this change.<\/p>\n\n

1. Upgrade to Enketo Express 1.86.x very soon<\/h4>\n\n

It is best to first upgrade to one of the 1.86.x versions as soon as possible. This version includes a change that will provide a helpful dialog to users letting them know when to refresh the webform. This will reduce the need for user support by you. Note that the (presumably) largest Enketo Express users, KoboToolbox<\/a> and Ona<\/a> have already upgraded to 1.86.x and have not reported any issues.<\/p>\n\n

2. Upgrade to Enketo Express 2.x.x at least one week later but before Chrome 83 is released<\/h4>\n\n

The rationale for waiting at least a week, is to give most of your users some time to update their cached Enketo application (and get the helpful modal dialog). They may not open their webforms every day or may be out in the field without Internet. You will of course know better what amount of time is appropriate for your users.<\/p>\n\n

Farewell Internet Explorer<\/h3>\n\n

The switch to the new offline caching technology also means that we have to finally completely drop support for Internet Explorer. Internet Explorer users will be redirected to a modern-browsers page<\/a>.<\/p>\n\n

A Node.js change in version 2.1.0.<\/h3>\n\n

Enketo Express version 2.1.0 and onwards will require Node.js version 12. Any Enketo Express version before 2.1.0 requires Node.js version 8. This is a good way to make this upgrade:<\/p>\n\n

    \n
  1. Remove the node_modules<\/code> folder from your Enketo Express installation<\/li>\n
  2. Upgrade Node.js to version 12<\/li>\n
  3. Upgrade Enketo Express to version 2.1.x or later<\/li>\n<\/ol>\n\n

    You may decide to skip 2.0.x and go straight to 2.1.x or later of course. There should be no problem doing that.<\/p>\n\n

    Feedback<\/h3>\n\n

    As always, we\u2019d love to get your feedback. Comment on this blog, tweet @enketo<\/a>, or post a message in the Enketo forum<\/a>. If you discover a bug, please let us know what browser you are using.<\/p>\n\n"},{"title":"Encryption","link":{"@attributes":{"rel":"alternate","href":"https:\/\/blog.enketo.org\/encryption\/"}},"updated":"2018-10-05T00:00:00+00:00","id":"https:\/\/blog.enketo.org\/encryption\/","content":"

    Enketo now has full support for encryption-enabled forms! This long-requested feature is compatible with other tools in the Open Data Kit<\/a> ecosystem and of course in particular with ODK Briefcase<\/a>, the primary tool for decryption.<\/p>\n\n

    Why use this<\/h3>\n\n

    Enketo has always facilitated encryption of data during transport<\/strong> from the browser to the data server (e.g. to Aggregate, Ona, KoboToolbox) just like any website that uses an \u201chttps\u201d web address (note that both Enketo and the data server need to be using https). However, some projects also require sensitive data to be securely encrypted while it is still stored on the device and while it is stored on the data server<\/strong>. This new feature responds to that requirement.<\/p>\n\n

    How it works<\/h3>\n\n

    Encryption takes place as soon as the record is finalized and saved.<\/p>\n\n

    A random single-use encryption key is generated by Enketo, and this is used to symmetrically encrypt all data including file uploads such as photos. The form definition includes a public RSA key that is used by Enketo to asymmetrically encrypt<\/a> the single-use encryption key. The resulting asymmetrically-encrypted symmetric encryption key<\/em> is passed along with the submission. For those of you interested in the full technical details on the encryption algorithms see this specification<\/a>.<\/p>\n\n

    Once the submission has been received on the data server, it can be decrypted in ODK Briefcase. This can be done by pulling<\/em> the submissions and using the private RSA key to decrypt the symmetric encryption key that was used to encrypt the data.<\/p>\n\n

    The only person that should have access to the private key is the person that is entrusted with decrypting the data.<\/p>\n\n

    Auto-saving and saving as draft<\/h3>\n\n

    For encryption-enabled forms, Enketo will automatically de-activate 2 features that normally exist in offline-enabled webform views: the auto-save<\/a> feature and the ability to save a record as draft. This is done to avoid storing sensitive data without encryption, because even Enketo will not be able to decrypt the data once it is encrypted.<\/p>\n\n

    How to use<\/h3>\n\n

    To use this feature the XLSForm needs to include a public_key<\/em> in the settings sheet (and keep the matching private key secret). See the XLSForm specification<\/a> and ODK documentation<\/a> for more details. Note that some older tutorials mention an additional need for a submission_url<\/em>. This can be ignored, as that is actually an independent feature that does not relate to encryption.<\/p>\n\n

    XML wizards may be interested in looking at the XForms Specification<\/a>.<\/p>\n\n

    Limitations<\/h3>\n\n

    The only known limitation is that encrypting photos, videos, audio and other uploaded files puts a heavy burden on a low-spec device. If the survey includes file uploads, it is therefore required to always test your survey on actual devices that will be used during collection. In addition, you may want to ensure that the uploaded file size is limited. In the future, a feature will be added to facilitate this by automatically transforming the image to a pixel size that can be set in the XLSForm.<\/p>\n\n

    Internet Explorer does not support encryption and will just show a helpful warning during load. To work around that lack of support, the best approach is to simply make sure to never use that awful browser for any reason.<\/p>\n\n

    Future<\/h3>\n\n

    Depending on whether there is a demand, interest, and funding for this, some clever developer could now create a fancy command-line or desktop tool for decryption as an alternative to ODK Briefcase. This would seem like a really fun project for a JavaScript\/Electron developer to take on, and I think the ODK community will welcome it! If interested, let us know and we will quickly split off Enketo\u2019s internal encryption module as a separate npm module so it can be used by multiple projects and be centrally maintained.<\/p>\n\n

    At some point it may become worthwhile to start a discussion within the ODK group on a new modern encryption specification that is simpler and faster, provides even better security, and offers an easier out-of-the-box implementation across platforms. There is a straightforward path towards adding a new encryption algorithm without affecting users or compatibility of Briefcase with older encrypted data.<\/p>\n\n

    Acknowledgements<\/h3>\n\n

    This feature was sponsored by the London School of Hygiene & Tropical Medicine<\/a> as part of their program to provide LSHTM Open Research Kits<\/a> to support global health research. Many thanks to LSHTM ORK for funding this important feature!<\/p>\n\n

    Also many thanks to the amazing ODK developers Guillermo Gut\u00e9rrez (ggalmazor) and H\u00e9l\u00e8ne Martin (lognaturel) for helping out!<\/p>\n\n

    Feedback<\/h3>\n\n

    As always, we\u2019d love to get your feedback. Comment on this blog, tweet @enketo<\/a>, or post a message in the Enketo forum<\/a>. If you discover a bug, please let us know what browser you are using.<\/p>\n\n"},{"title":"July 2018 Update","link":{"@attributes":{"rel":"alternate","href":"https:\/\/blog.enketo.org\/jul-2018-update\/"}},"updated":"2018-07-30T00:00:00+00:00","id":"https:\/\/blog.enketo.org\/jul-2018-update\/","content":"

    Improvements<\/h3>\n\n

    This is a snapshot of the main improvements to Enketo in the past 6 months:<\/p>\n\n