Online Learning Platforms: A Complete Overview
Five platforms reviewed on the criteria that matter most: content depth, pricing, certificate value and ease of use for learners based in Spain.
How the Platforms Compare at a Glance
The table below uses the criteria we tested most thoroughly. Ratings reflect our editorial judgement, not sponsored content.
| Platform | Free Option | Certificates | Course Count | Mobile App | Best For |
|---|---|---|---|---|---|
| Coursera | Audit only | Verified | 7,000+ | Yes | Academic credentials |
| Udemy | Paid | Completion only | 200,000+ | Yes | Practical skills |
| edX | Free audit | Verified | 4,000+ | Yes | STEM and business |
| Khan Academy | Fully free | None | 10,000+ lessons | Yes | Foundations & maths |
| Udacity | Some free | Nanodegree | 200+ | Limited | Tech careers |
Coursera: University-Backed Learning at Scale
Founded in 2012 by Stanford professors Andrew Ng and Daphne Koller, Coursera has built its reputation on academic partnerships. Today it works with over 300 universities and companies, including Google, IBM and the University of Michigan.
The platform offers individual courses, Specialisations (bundles of related courses), Professional Certificates and even full online degrees from accredited institutions. Prices range from free (audit mode) to several thousand euros for degree programmes.
What works well on Coursera
The structured learning paths are particularly useful if you have never studied a subject before. Each Specialisation builds on the previous course, so there is rarely a gap in knowledge. Video lectures are generally well produced, and assignments are peer-reviewed, which adds a layer of accountability.
Where Coursera falls short
Auditing a course gives access to video content but not graded assignments, which limits the learning experience. The subscription model (Coursera Plus costs around €50/month) is worth it only if you plan to take multiple courses in a year. For a single course, the one-off price can feel steep compared to Udemy.
Coursera's financial aid programme offers free access to courses for learners who cannot afford the fees. Applications take about 15 days to process and approval rates are generally high. See Coursera Financial Aid for details.
Coursera vs Udemy: Full Breakdown
Detailed comparison →Udemy: The Marketplace Approach to Online Education
Udemy operates as an open marketplace: anyone can create and sell a course. This results in extraordinary breadth — over 200,000 courses in 75 languages — but quality varies widely between instructors. The key to getting value from Udemy is learning how to identify good courses before purchasing.
Why Udemy Works for Practical Skills
Udemy courses are almost always priced between €10 and €20 when purchased during a promotional period, which happens most months. Once you buy a course, you keep access permanently — even if the instructor updates the content. This makes it ideal for technical skills like web development, data analysis or graphic design, where staying current matters.
The rating system is reasonably reliable. Courses with over 10,000 ratings and an average above 4.4 are almost always worth the discounted price.
What Udemy Cannot Offer
Udemy completion certificates carry less weight with employers than verified certificates from Coursera or edX. If your goal is career advancement based on the credential itself, Udemy is a poor choice. Additionally, the platform has no formal quality review before a course is published, meaning you may encounter outdated or low-effort content that slipped through.
There is also no structured learning path built into the platform — you have to curate your own curriculum, which can be confusing for beginners.
edX: Academic Standards with Open Access
Created by MIT and Harvard in 2012, edX was designed to make world-class education accessible to anyone with an internet connection. It has since expanded to include over 160 institutional partners and now offers MicroMasters programmes that can count toward a full master's degree at some universities.
The audit option is edX's most distinctive feature: most courses can be taken for free, with access to all course materials. You pay only if you want a verified certificate. This is a meaningful difference from Coursera, where auditing limits what you can access.
edX was acquired by 2U in 2021. The platform still operates under the edX brand and continues to expand its course catalogue. Some changes to the pricing structure have been introduced, so always verify current audit availability before starting a course.
Khan Academy: Free, Forever
Khan Academy is the rare platform that has remained free since its founding by Sal Khan in 2008. Funded by donations from organisations like the Bill & Melinda Gates Foundation, it offers thousands of lessons in mathematics, science, programming, history and economics.
For Spanish learners, Khan Academy is an excellent supplement to university study or a way to build missing foundations before tackling a paid course on another platform. The interactive exercises and immediate feedback make it particularly effective for maths at any level.
The main limitation is depth: Khan Academy covers concepts thoroughly but does not go deep enough for professional-level or specialised knowledge. Think of it as a very good foundation layer rather than a complete learning solution. Learn more at khanacademy.org.
When to Use Khan Academy
- Brushing up on school maths before an exam
- Learning programming fundamentals for free
- Helping children with school subjects
- Understanding economics and personal finance basics
- Preparing for standardised tests (SAT, GMAT concepts)
Udacity: Nanodegrees for Tech Careers
Udacity is the most expensive platform on this list, but it targets a specific outcome: getting a job in a tech field. Its Nanodegree programmes are designed with industry partners including Amazon, Google and Facebook, and every programme includes career services, code review and mentor support.
A typical Nanodegree takes 3 to 6 months at 10 hours per week and costs between €300 and €600 per month. The investment is significant, but the programme structure and personal feedback are things other platforms cannot match at the same level.
Udacity makes the most sense for learners who are already in a tech role and want to advance, or for career changers who are fully committed and want structured guidance. For casual learners, the cost is not justified.
Popular Nanodegree Tracks
- Machine Learning Engineer
- Data Analyst
- Front End Web Developer
- Cloud Developer
- Product Manager