Latest version

Machine Learning is certainly picking up, we are getting a lot more users and requests and we are really excited by this. So we started 2016 by making an maintenance update, mostly fixes:

  • Fixed broken xml schema links
  • Fixed keyword extraction for classifiers using other than uni-grams (e.g. sentiment classifier)
  • Fixed Twitter external login
  • Updated backend libs to latest
  • Added service terms
  • Pricing adjustments the indie local server 99EUR->299EUR, Enterprise 5999EUR->3999EUR

Right now we are working on the much wished-for Json Api that will be in the next major release.

Update with limit changes

The last major update has been running very smoothly, this is the first patch since!

Max request size limit increased

After feedback from the community I’ve increased the maximum allowed request size from 1MB to 3MB. I will monitor the servers and make sure this works fine. Maybe it’s possible to increase it further.

Max query string length increase

After the last update, when I updated the IIS server the default max request string url length was lower then previous. Thanks Liz who noticed this. I’ve not set the max size to 65kb.

Max free calls per day decreased

When I looked at the call statistics it didn’t make much sense to offer 5000 free calls per day. Most people aren’t even close to this, by lowering it to 1000 calls per day only a few will be affected, but most will not notice anything. This is also motivated by looking on competitors free limits and 1000 calls per day is still very generous. Let me know if you have any questions about this.


Besides fixing some typos (thanks to everyone who reported) I’ve made it so you can’t publish untrained classifiers and fixed a so the front page buttons work better on small displays. I’ll also unpublished previous classifiers that are untrained and published.


I am extremely happy with the performance of the new Sentiment classifier. It uses a new version of the classifier that looks at combinations of words among other things. Tests show that this type of classifier improves the performance of all tested data sets, therefore I am trying to figure out how to use it for all new classifiers, but it does require some work.

Let me know if you have any questions.


Sentiment Analysis Api

A Sentiment analyzer tells you if a text it’s positive or negative. For example “I love the new Mad Max Fury road” (positive) or “i am not impressed by the bike” (negative). The Sentiment classifier hosted by uClassify is very popular so I decided to spend some time on improving it.


The goal was to improve the classification accuracy, especially for short texts such as Twitter messages, Facebook statuses or other snippets while maintaining high quality results on texts with more information.

The old Sentiment classifier was built by 40k amazon product reviews. The straight forward way to improve a classifier is to add more data. Thanks to the Internet we were able to find multiple data sources we could train our classifier on. In fact it’s now trained on 2.8 million documents!

The results are good very good, the accuracy on large documents (reviews) went from about 75% to 83%. Tweets went from 63% to about 77%.

You can play with it here there is also an API available (free to use).

Datasets used are from sentiment-140 (twitter), amazon product reviews and rotten tomatoes.

Image by Anna Gathu

New 64-bit local server

As a part of the uClassify upgrade I’ve recompiled the local server for 64-bit. This was necessary since I’m working on a huge classifier for sentiment and needed the corpus tool to be able to handle more then what 32-bit pointers could hold.

If you are running a local uClassify server, you can download the 64-bit (and 32-bit) here. The 64-bit server is already used in production for uClassify and should be pretty well tested by now.

You can read more about the local uClassify server here.

uClassify is updating

The old uClassify site has been set to read-only and the database & classifier migration has been done. Now we are just waiting for the DNS to propagate over the nets before the new site can be taken into use. This time on an elastic IP so hopefully this we won’t have to do anymore of those ‘waiting’ operations in the future.

Hopefully it has been fully propagated within 24h.

Let me know if you have any trouble with your account.

Update: Thursday 14/5 May (read-only-mode)

Exciting times! I’ve decided to push the next update out on Thursday May the 14th (2015). Normally you won’t notice updates but this one is huge.

I’m migrating servers from old ‘Classic’ Amazon EC2 to their new cloudy thing. This will require a DNS update which takes time to propagate over internet before it’s completely done.

Read Only Mode during the transition

Since this also involves a database migration step, I will set the uClassify to ‘read-only’ until it’s done. This means that all the read calls (classify etc) should continue to work during the transition while write calls won’t go through (creating, training classifiers). You won’t be able to register as a new user during this time either. DNS updates usually takes about 48h.

What will be new

First, I’ve done extensive testing to make sure the API will behave exactly the same. If I have not missed anything your app will continue to work without any changes.

The major ‘visible’ changes are:

– A new responsive bootstrap UI (the vanilla theme, somehow cosmetics always ends up last on my prio lists :)

– To make it more secure the entire site will be in SSL (don’t worry all the API links without https:// will still work).

– It will be possible to sign in via Twitter, Facebook and Google.

– You can train classifiers by uploading files.

This is the first of a few major updates for uClassify, it doesn’t introduce much new cool fancy stuff but it’s a very important updates that paves the road for the stuff I actually want to add, such as an JSON api.

If you have any questions please don’t hesitate to contact me. (contact AT uclassify DOT com)

Next update and future plans

Lately uClassify has gotten a lot of attention and the user community has grown at a faster rate. We are getting more requests and inquires from our customers and it feels like machine learning is something that many people know of, not only the tech savvy geeks

Whats in the next update

For a couple of months now I’ve been reworking the both the front end and back end to make it easier to go forward. It feels like a necessity to get some of the tech up to date. After all the tech is at least six years old.

The site will be replaced with a modern bootstrap powered front end. Making it much more responsive and easy to maintain. There will also be a few new features in the first release, e.g. ability to upload files to train classifiers. It will also be possible to log in via Google, Twitter and Facebook.train_from_files

The backend is also being reworked to make it easier to work with. Those changes will be completely invisible to users and all public APIs will remain the same.

I hope to have all of this done before the end of June 2015.

Future plans

– Once all the new code is in place and the service is up and running I intend to add a complete JSON Api for the service. E.g. right now you need to use XML for batching calls.

– Open source C# and Java libs for calling the API.

– Add more and better classifiers. Today it’s easier to find good training data for classifiers.

– Classifier performance, I’ve a few ideas of how to improve the accuracy of the classifier further.

Possible to upgrade your account

uClassify has been around since October 2008, and to date has almost 15000 registered users and nearly 2000 classifiers. All this time the web api has been completely free with no restrictions what so ever (number of calls, classifiers, size of classifiers etc). But lately we have gotten a lot more traffic over our web api. This is of course a lot of fun but it also adds more server cost. Therefore I want to try to introduce payment options for those who can pay but keep it free for the majority of users.

Free, Indie, Professional and Enterprise Accounts

What I want to do is to introduce a pricing model that doesn’t affect the majority of users and hopefully only affects those who can afford to pay.

After analyzing the logs I’ve found only a few percent of the users make more than 1000 calls per day. Therefore I decided to introduce a limit of max 5000 calls per day for free accounts. Keeping in mind that I want it affordable for everyone I introduced both ‘Indie’ and ‘Professional’ accounts. Both with a cap of 100.000 calls per day. The indie account is for smaller companies (<100.000€ yearly revenue). The pricing for an Indie account is initially set to 9€/month and for professional 99€/month.

On top of that there is an option to upgrade to 1.000.000 calls / day for a price of 299€/month for high end users. Also I will offer a free Academic account with 1.000.000 calls / day cap for researchers.

To sum up
Free 5000 calls/day
Indie* 9€/month -> 100.000 calls/day
Professional 99€/month -> 100.000 calls/day
Enterprise 299€/month -> 1.000.000 calls/day
Academic 1.000.000 calls/day

*Indie=For small companies and private persons with yearly revenue < 100.000€ Subscription will be done via Paypal.

What will happen to existing accounts?

If you already have a uClassify account it will be upgraded to an Enterprise account with X months expiry time. All of those who are likely to be affected will be emailed with a heads up. But most of you won’t notice this change.

The system will likely be implemented during the nearest weeks.

I am open to suggestions, if you have feedback or think this sucks please let me know! (contact AT uclassify DOT com)

Sentiment analysis with keyword extraction

Lately we have been getting a lot requests to our sentiment classifier, many are from social media analyst companies. In fact our sentiment analysis is now the most popular classifier at uClassify!

I just wanted to share something that could be usable for you guys. By using our latest Api call, ‘classifyKeywords’ you can see which keywords are the strongest triggers for the positive and negative classes. This could reveal additional valuable information for your clients.

For example, if you use the keyword analysis on a long product review, you could use the keywords to extract the sentences where the product is mentioned in a positive or negative way. Why not highlight it in green or red? Highlighting sentences will give a very good overview for human reviewers.

Here is how an XML request looks like (just swap ‘classify’ for ‘classifyKeywords’):

<?xml version=”1.0″ encoding=”utf-8″ ?>
<uclassify xmlns=”” version=”1.01″>
<textBase64 id=”tweet1″>bm93IHNvbWV0aW1lcyBpIHdvbmRlciB3aGF0</textBase64>
<readCalls readApiKey=”YOUR_READ_API_KEY_HERE”>
<classifyKeywords id=”ClassifyKeywords” username=”uClassify” classifierName=”Sentiment” textId=”tweet1″/>

You can find more info about ‘classifyKeywords’ here.

The sentiment classifier is described in more detail here.


Text Analytics Api Overview

uClassify is an open tool to allow users to create and share classifiers. Todo this uClassify provides three APIs (URL, XML and Local Server), here is a short overview and comparison of those.


The URL API is simple to use, just send an GET request with an URL to get a response.

For example making a sentiment classification (sign up for a free read api key):

The response will be in XML or alternatively JSON. You can classify a text or let uClassify download an URL for you and classify the content (optionally with or without the HTML).

When to use the URL API
– Want to get up and running quickly
– Low volumes of classifications (can be slow on many requests at once)
– Each text is only run through one classifier (otherwise you should batch with XML API)
– If you only is interested in classifying and not training or other fancy features.

The URL API documentation can be found here.


With the XML API you can do everything. You can create classifiers, train them, classify, extract keywords and more. Another important feature is that you can batch calls. This means that you can get thousands of, say, tweets or blog posts, classified in one single request as long as the request string is less than 1 MB.

To make an XML request, you simply build an XML string and POST it to: on port 80.

Here is how you batch two calls into one request:

<?XML version="1.0" encoding="utf-8" ?>
<uclassify xmlns="" version="1.01">
    <textBase64 id="UnknownFantasyText1">SXcgYklRdHFEYXEgYklsZW5namFq</textBase64>
    <textBase64 id="UnknownFantasyText2">UGFkb2wgcmFpZCwgYXRoYW4gaGVuZGFk</textBase64>
  <readCalls readAPIKey="YOUR_READ_API_KEY_HERE">
    <classify id="Classify1" classifierName="FantasyLanguage" textId="UnknownFantasyText1"/>
    <classify id="Classify2" classifierName="FantasyLanguage" textId="UnknownFantasyText2"/>

When to use the XML API
– Gain performance by batching multiple calls into one request
– Need access to the full API (classifier creation, training, keywords etc)
– This is the recommended way

You can find the complete documentation here.

Local Server

As a final option you can run a local classification server. This is for users who have huge amounts of data to process.

The API is pretty much the same as the XML API except that no authentication is needed.

When to use a local classification server
– You have huge amounts of data to process
– CPU performance is very important (you don’t have to share CPU cycles with other uClassify users)
– Install the server in your own data centre, to avoid any network lag to
– Have full control over the server

You can find more info here and the technical server manual.