Artificial Intelligence

Hire the Top 3% of Freelance AI Engineers

Toptal is a marketplace for top artificial intelligence engineers, programmers and experts. Top companies and start-ups choose Toptal’s AI engineers for their mission critical software projects.

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Clients Rate Toptal AI Engineers4.3 / 5.0on average across 394 reviews as of Jun 1, 2023

Hire Freelance AI Engineers

Abhimanyu Veer Aditya

Freelance AI Engineer

United StatesToptal Member Since May 7, 2019

Abhimanyu is a machine learning expert with 15 years of experience creating predictive solutions for business and scientific applications. He’s a cross-functional technology leader, experienced in building teams and working with C-level executives. Abhimanyu has a proven technical background in computer science and software engineering with expertise in high-performance computing, big data, algorithms, databases, and distributed systems.

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Vince Jankovics

Freelance AI Engineer

United KingdomToptal Member Since October 18, 2018

Vince is an engineer with expertise in machine learning and robotics. He has experience developing autonomous systems and artificial intelligence with an emphasis on perception, decision making, and control. He is fluent in Python and C++ and has worked on a variety of projects as a consultant, helping clients achieve their goals.

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Dan Napierski

Freelance AI Engineer

United StatesToptal Member Since April 28, 2016

Dan is a software architect and technology professional focusing on applications of blockchain technologies. He has years of experience providing professional consulting services to clients ranging from startups to global corporations. He specializes in bringing rigorous testing and bulletproof code to tough engineering challenges. He has deep expertise in many aspects of artificial intelligence, blockchain, machine learning, and automation.

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Dilip Mathew Thomas

Freelance AI Engineer

IndiaToptal Member Since April 11, 2019

Along with earning a PhD in computer science and engineering, Dilip has over a decade of experience in the industry. Since 2015, he's been focusing on projects related to machine learning and deep learning. Dilip has an eye for detail which helps in working closely with domain scientists and improving the accuracy and reliability of models for fine-grained image classification, object detection and segmentation, natural language processing, time-series forecasting, and generative AI.

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Rajeev Gupta

Freelance AI Engineer

IndiaToptal Member Since July 22, 2019

Rajeev is passionate about data and machine learning and has more than five years of experience in data science projects across numerous industries and applications. He's currently focused on cutting-edge technologies such as TensorFlow, Keras, deep learning, and most of the Python data science stack. Rajeev has used these skills to solve many real business problems in NLP, image processing, and time series domains.

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Miguel Duarte

Freelance AI Engineer

PortugalToptal Member Since August 20, 2015

Miguel plans and implements full-stack solutions, focusing on solving problems and maximizing users' and other stakeholders' value through a pragmatic and technology-agnostic approach. He leans into his scientific research background, where he developed complex systems such as robotic simulation platforms and distributed computing systems, to learn and apply new technologies quickly.

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Goran Trlin

Freelance AI Engineer

Bosnia and HerzegovinaToptal Member Since November 8, 2015

Goran is a talented computer programmer with 15 years of experience. He has extensive experience in dozens of programming languages and platforms and is always striving to learn more. He is interested in a wide range of software engineering topics and always on the lookout for new and exciting projects.

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Josip Bojčić

Freelance AI Engineer

CroatiaToptal Member Since November 27, 2015

Josip is a computer science professional with skills from a variety of fields. He works well solo or on a team. He's highly motivated in tackling all kinds of CS problems; particularly in algorithms, artificial intelligence, databases, and web development. He's continuously trying to improve, learn more and gain new experiences. Recently, Josip has been working mostly with Angular, React, and .NET.

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A Hiring Guide

Guide to Hiring a Great AI Engineer

AI development is already blazing fast and ever more popular. But not everyone tasked with hiring AI engineers knows what they're looking for. After interviewing industry experts, we've summarized their hiring practices for you in this trusty guide.

Read Hiring Guide
Toptal in the press

... allows corporations to quickly assemble teams that have the right skills for specific projects.

Despite accelerating demand for coders, Toptal prides itself on almost Ivy League-level vetting.

Our clients
Building a cross-platform app to be used worldwide
Thierry Jakicevic
Building a cross-platform app to be used worldwide

Tripcents wouldn't exist without Toptal. Toptal Projects enabled us to rapidly develop our foundation with a product manager, lead developer, and senior designer. In just over 60 days we went from concept to Alpha. The speed, knowledge, expertise, and flexibility is second to none. The Toptal team were as part of tripcents as any in-house team member of tripcents. They contributed and took ownership of the development just like everyone else. We will continue to use Toptal. As a start up, they are our secret weapon.

Brantley Pace, CEO & Co-Founder


I am more than pleased with our experience with Toptal. The professional I got to work with was on the phone with me within a couple of hours. I knew after discussing my project with him that he was the candidate I wanted. I hired him immediately and he wasted no time in getting to my project, even going the extra mile by adding some great design elements that enhanced our overall look.

Paul Fenley, Director

K Dunn & Associates

The developers I was paired with were incredible -- smart, driven, and responsive. It used to be hard to find quality engineers and consultants. Now it isn't.

Ryan Rockefeller, CEO


Toptal understood our project needs immediately. We were matched with an exceptional freelancer from Argentina who, from Day 1, immersed himself in our industry, blended seamlessly with our team, understood our vision, and produced top-notch results. Toptal makes connecting with superior developers and programmers very easy.

Jason Kulik, Co-Founder


As a small company with limited resources we can't afford to make expensive mistakes. Toptal provided us with an experienced programmer who was able to hit the ground running and begin contributing immediately. It has been a great experience and one we'd repeat again in a heartbeat.

Stuart Pocknee , Principal

Site Specific Software Solutions

We used Toptal to hire a developer with extensive Amazon Web Services experience. We interviewed four candidates, one of which turned out to be a great fit for our requirements. The process was quick and effective.

Abner Guzmán Rivera, CTO and Chief Scientist

Photo Kharma

Sergio was an awesome developer to work with. Top notch, responsive, and got the work done efficiently.

Dennis Baldwin, Chief Technologist and Co-Founder


Working with Marcin is a joy. He is competent, professional, flexible, and extremely quick to understand what is required and how to implement it.

André Fischer, CTO


We needed a expert engineer who could start on our project immediately. Simanas exceeded our expectations with his work. Not having to interview and chase down an expert developer was an excellent time-saver and made everyone feel more comfortable with our choice to switch platforms to utilize a more robust language. Toptal made the process easy and convenient. Toptal is now the first place we look for expert-level help.

Derek Minor, Senior VP of Web Development

Networld Media Group

Toptal's developers and architects have been both very professional and easy to work with. The solution they produced was fairly priced and top quality, reducing our time to launch. Thanks again, Toptal.

Jeremy Wessels, CEO


We had a great experience with Toptal. They paired us with the perfect developer for our application and made the process very easy. It was also easy to extend beyond the initial time frame, and we were able to keep the same contractor throughout our project. We definitely recommend Toptal for finding high quality talent quickly and seamlessly.

Ryan Morrissey, CTO

Applied Business Technologies, LLC

I'm incredibly impressed with Toptal. Our developer communicates with me every day, and is a very powerful coder. He's a true professional and his work is just excellent. 5 stars for Toptal.

Pietro Casoar, CEO

Ronin Play Pty Ltd

Working with Toptal has been a great experience. Prior to using them, I had spent quite some time interviewing other freelancers and wasn't finding what I needed. After engaging with Toptal, they matched me up with the perfect developer in a matter of days. The developer I'm working with not only delivers quality code, but he also makes suggestions on things that I hadn't thought of. It's clear to me that Amaury knows what he is doing. Highly recommended!

George Cheng, CEO

Bulavard, Inc.

As a Toptal qualified front-end developer, I also run my own consulting practice. When clients come to me for help filling key roles on their team, Toptal is the only place I feel comfortable recommending. Toptal's entire candidate pool is the best of the best. Toptal is the best value for money I've found in nearly half a decade of professional online work.

Ethan Brooks, CTO

Langlotz Patent & Trademark Works, Inc.

In Higgle's early days, we needed the best-in-class developers, at affordable rates, in a timely fashion. Toptal delivered!

Lara Aldag, CEO


Toptal makes finding a candidate extremely easy and gives you peace-of-mind that they have the skills to deliver. I would definitely recommend their services to anyone looking for highly-skilled developers.

Michael Gluckman, Data Manager


Toptal’s ability to rapidly match our project with the best developers was just superb. The developers have become part of our team, and I’m amazed at the level of professional commitment each of them has demonstrated. For those looking to work remotely with the best engineers, look no further than Toptal.

Laurent Alis, Founder


Toptal makes finding qualified engineers a breeze. We needed an experienced ASP.NET MVC architect to guide the development of our start-up app, and Toptal had three great candidates for us in less than a week. After making our selection, the engineer was online immediately and hit the ground running. It was so much faster and easier than having to discover and vet candidates ourselves.

Jeff Kelly, Co-Founder

Concerted Solutions

We needed some short-term work in Scala, and Toptal found us a great developer within 24 hours. This simply would not have been possible via any other platform.

Franco Arda, Co-Founder

Toptal offers a no-compromise solution to businesses undergoing rapid development and scale. Every engineer we've contracted through Toptal has quickly integrated into our team and held their work to the highest standard of quality while maintaining blazing development speed.

Greg Kimball, Co-Founder

How to Hire AI Engineers through Toptal


Talk to One of Our Industry Experts

A Toptal director of engineering will work with you to understand your goals, technical needs, and team dynamics.

Work With Hand-Selected Talent

Within days, we'll introduce you to the right AI engineer for your project. Average time to match is under 24 hours.

The Right Fit, Guaranteed

Work with your new AI engineer for a trial period (pay only if satisfied), ensuring they're the right fit before starting the engagement.

Find Experts With Related Skills

Access a vast pool of skilled developers in our talent network and hire the top 3% within just 48 hours.


  • How are Toptal AI engineers different?

    At Toptal, we thoroughly screen our AI engineers to ensure we only match you with talent of the highest caliber. Of the more than 200,000 people who apply to join the Toptal network each year, fewer than 3% make the cut. You'll work with engineering experts (never generalized recruiters or HR reps) to understand your goals, technical needs, and team dynamics. The end result: expert vetted talent from our network, custom matched to fit your business needs.

  • Can I hire AI engineers in less than 48 hours through Toptal?

    Depending on availability and how fast you can progress, you could start working with an AI engineer within 48 hours of signing up.

  • What is the no-risk trial period for Toptal AI engineers?

    We make sure that each engagement between you and your AI engineer begins with a trial period of up to two weeks. This means that you have time to confirm the engagement will be successful. If you're completely satisfied with the results, we'll bill you for the time and continue the engagement for as long as you'd like. If you're not completely satisfied, you won't be billed. From there, we can either part ways, or we can provide you with another expert who may be a better fit and with whom we will begin a second, no-risk trial.

Artificial Intelligence

How to Hire a Great AI Engineer

Artificial intelligence (AI) signals forward-thinking and cutting-edge technology to developers and the world. That’s why the process you use to hire AI engineers is now more important than ever.

Many engineers are eager to pivot their careers toward AI development. Creative new applications of artificial intelligence in software development are exciting, but our focus here won’t be on applying existing AI technology services. Instead, we’re looking at how to hire AI engineers capable of developing such services in the first place.

We spoke to leading AI hiring managers about how they screen for the best candidates for their teams. If you’re already comfortable with that, feel free to jump into our section on interview topics.

Finding AI Engineer Candidates

In many ways, finding AI engineers is standard fare: Local outreach, word-of-mouth networking, or exposing the more interesting problems you’re working on via social media are all good tactics.

As mentioned, you may find candidates who are experts at applying AI services, but who are certainly not skilled at pushing into new areas of research. It’s akin to hiring a Linux kernel hacker compared with someone who simply uses Linux as their desktop OS. There are different levels of experience and skill to be seen in both roles, but at their core they’re wildly different. Anyone involved in hiring an AI engineer—recruiters and HR departments included—must understand this distinction.

In fact, one hiring manager was surprised at how many self-styled AI experts would apply for advanced jobs like this but not even understand basics “like algorithms and big-O notation, much less why you would prefer to use a U-net or a resnet or straight machine learning regression versus a complex CNN.”

Sometimes you simply need to call a bluff on someone’s CV. But for applicants who are both honest and self-aware enough, a detailed enough job posting will help filter out a least a few non-starters.

To cite a couple examples of job postings from Matterport:

“We have a broad agenda for deep learning, including semantic labeling and segmentation, 3D object classification and pose estimation, depth from RGB, estimation of unseen 3D surfaces, texture/depth in-filling, key point matching, and dense stereo. We’re also working closely with some of the leading academic research labs in the country.”

The wording we highlighted above should function as an immediately red flag to a candidate who is used to calling the AI cloud for results but would be way in over their head in an AI engineering position. Our second example is perhaps even more direct:

“As a member of the computer vision team, you’ll be responsible for developing robust completely-automated computer vision algorithms to handle any real-world environment…

“We work on […] point cloud alignment, generation/texturing of 3D meshes from point clouds, 3D mesh manipulation, camera calibration, SLAM, multi-view stereo, machine learning, and semantic understanding.

There’s no room for mistake here. If an applicant tries to fudge their way into such a job, it should be very clear at any step from your background check through interviewing that they are not up to the task. Asking your most critical questions up front at each stage—ideally, your candidate will be returning the favor—will also help.

Job descriptions like the above will also shield you from applicants who perhaps have the skill level but not specific expertise. This may or may not be what you want, though.

Roles and Technical Areas for AI Engineers

There are several technical areas for which you may be aiming to hire. Machine learning—specifically computer vision—is one of the most competitive subsets to fill, as is natural language processing.

It’s important to focus on specifics. That said, one AI hiring manager advised us:

Cast a wider net first. Generic roles like ‘data scientist’ or ‘machine learning scientist’ can mean a lot of different things. If you have a specific domain, ‘computer vision engineer’ or ‘natural language processing’ mean something specific.

In other words, you don’t want high-quality, moldable talent to slink away due to categorical differences that could be overcome with clear direction. Some of these finer details can be sussed out during the interview problem-solving process while you decide whether your candidate has the right mix of personality and skills.

So how specific should you get? Depends on your urgency and whether you’re getting too many or too few applicants. You can always adjust your description if need be.

Academic Publications, Open-source Projects, and Work-life Balance

Most AI engineers will have a degree. Many will also have written and published post-graduate research. But is it important for AI engineers to have open-source projects available as part of their resume? Not always—if you have them, they’ll be looked at, but it’s not necessarily assumed that every spare moment of your life goes into AI work.

In fact, a mature AI engineer is expected to have other obligations. This was a refreshing realization and may even signal a change in culture. To attract the best candidates to your team, respect their commitment to personal time. Their interest in artificial intelligence may well drive their problem-solving passion, but ultimately it may be most helpful to promote a culture of balance.

Math and AI Development

AI development’s popularity means it’s crucial to, assess the mathematical competence of candidates. Taking math skills into account separates those with experience in computer science and interest in AI from those who will be truly effective AI engineers.

A deep knowledge of math—specifically linear algebra—was a good indicator of whether or not an AI engineer would be up to the task. Your candidate should also be able to program and to template real-world solutions: While mathematical knowledge is critical to the role, it does not necessarily mean aptitude in putting that knowledge into practice.

As raw data can be quite messy, you’ll want to test your candidates’ knowledge and speed at cleaning and fixing data before they build models. Additionally, are they able to create rules based on those models to make predictions? Your interviewee should be aware of the biases within their data and should show initiative in thinking of how their data set operates in real life. An AI engineer should also know to consider the ethical duties of working with the data they are cleaning and fixing.

Tried and True Questions

As you gather and create artificial intelligence interview questions, be consistent. The managers we spoke with generally use several variations of a preferred set of questions. This will more accurately measure their knowledge, as well as their fit within your team.

During an interview, it’s unlikely you’ll have time to train a network. However, you can judge an engineer’s knowledge of frameworks using a whiteboard to discuss structure and process.

One of the hiring managers we interviewed mentioned, “A lot of candidates know what Keras is and have run the demos in the examples directory and have seen OpenCV but can’t really tell you how RANSAC or graph cuts work.” As a hiring manager or team leader, acknowledge that while a candidate’s grasp of a framework is useful, fashions in math tend to change much more slowly. For example, Theano may be on its way out; but as its creators note, its concepts live on elsewhere in the ecosystem of deep learning frameworks.

So awareness of the math underlying a framework is indicative of a more versatile candidate. Encourage data application during the interview—but you’re testing math, primarily, not coding.

Example Scenarios

What sorts of problems would you present your candidates with? Again, AI is a wide field, so not all of these will apply to every specialization an AI engineer will face. But these will give you an idea of the depth you should get into:

  1. Suppose we have five-dimensional data vectors split apart. What would your candidate do with them? Ask them for more traditional techniques. What information can they gain using traditional math? Take note of their aptitude working with matrices, frame transformations, and as mentioned, linear algebra.
  2. Provide the candidate with an open-ended, publically available problem and then ask them to solve an NLP on the data to build a basic classifier or regression. There are many solutions, and maybe the interviewer can think of five ways of doing it themselves, even if none of them are the most valuable solution. Here you are looking for minimal performance, whether they can explain what errors it will produce, and how they would measure performance in the first place. Don’t provide any recommendations or cross-validation: This helps weed out people who are merely interested in AI from those who understand the topic deeply.
  3. For computer vision projects, give the AI engineer an image that has been unwrapped to be just a vector. You’ve taken every row and lined them up next to each other. Ask them to put it back in the shape that it was without the original dimensions. With a fixed number of pixels there will only be a certain number of variations. Define some metrics for defining which ratios are correct. Some notion of complexity—either they may look for a number of edges or apply some transform or large coefficients. They don’t need to be an expert to do something interesting. Pair that with practical problems—you can’t just do one.
  4. How would you use deep learning for an image classification task with relatively few examples? As deep learning uses complex models (large networks) the best way is to use a pre-trained network. This means the network parameters are already tuned and the limited data would be sufficient to train, especially since with a pre-trained network only the last layers require training. Data augmentation could also be used, which involves transforming the training data to obtain similar, but different training examples. For instance the training images can be slightly zoomed, rotated, reflected and so on.
  5. What would you look for in a pre-trained network and why? Ideally one trained on a similar dataset; a simpler one in the exploration phase, and then a larger one for fine tuning. Pre-trained networks are networks that have already been tuned to get excellent results on standard data sets, such as ImageNet. Your data set doesn’t have to be identical to one of these, but the closer it is, the better the results. Since there are both smaller and larger pre-trained network architectures available, you can start with a smaller one in order to test quickly, and if the results are promising, move on to a larger pre-trained network.
  6. A network sometimes overfits a training set. How would you detect and avoid this problem? Overfitting happens when the network does really well (small error) on the training set, and significantly worse on the test set. Small training sets are susceptible to this issue, since the network can end up learning their peculiarities instead of learning generally useful features. As mentioned, data augmentation effectively increases the number of available training samples, so it can help with overfitting. Other ways to prevent overfitting include dropout and regularization, which your candidate should be able to explain in detail.
  7. Is a multi-layer neural network with linear activation more powerful than a single layer linear neural network? Why? (A rather difficult one, but this would show great understanding of the consequences of linear functions.) Our intuition might tell us that a deep network might be more powerful than a shallow network. However, since each layer is a linear function, and the combination of linear functions is also linear, then no expressive power is gained.
  8. Why does a multi-layer neural network with sigmoid activations tend to behave linearly if it’s regularized strongly using L2 regularization? (Also difficult, but demonstrates knowledge of regularization and the behavior of the sigmoid function—which is used a lot.) First of all, we have to understand that L2 regularization tends to reduce the magnitude of the weights of the neural network. If we have strong regularization then they will tend to be close to zero, and the logits (the layer prior to the sigmoid activation) will be very small too. Now if you take a look at the sigmoid function below, you will notice that for inputs near zero, the function has a very linear shape/behavior. Therefore, if you regularize a sigmoid network too strongly, you will end up with something like a linear network, with very little expressive power.

The sigmoid function

Furthermore, some questions specific to deep learning:

  1. Why are ReLUs better activation functions for deep networks than, for example, sigmoid activations?
  2. In general, why could it be that the outputs of an autoencoders are blurrier than those of a GAN?
  3. Why is it that deep networks that use batch normalization are able to train faster?
  4. What is the basic idea behind residual connections?
  5. What is the basic idea behind the inception module?
  6. What are the benefits of SqueezeNet and how does the architecture achieve them?
  7. What is the main difficulty of training RNNs and what solutions are there?
  8. How can convolutional neural networks be used for time series analysis?

Remember, there’s no formula that applies to every business and project. If you can’t tell which questions and scenarios are applicable to your context, it’s wise to listen to team members who can.

Steps For Your AI Engineer Interviewees

This will vary depending on your team size.

On a small team, interviewees might expect a conversation. When leading a smaller team you need to consider both technical skill and fit within the team.

On a larger team, the hiring manager might be more concerned with whether or not this interviewee is embracing of company culture. If the hiring manager is out of their depth concerning the specifics of your department or project, the CTO is usually a major part of reaching out to candidates and having the initial conversation.

This initial conversation would last about ten minutes. If the candidate is successful, it’s the norm to have a sit-down with two to four members of the technical team. During this time, they may be asked to solve a preformed function or do some tensor boxing on a whiteboard.

It’s also important to tailor some of your questions to what the interviewee has claimed as their expertise. Due to the popularity of artificial intelligence and machine learning, it’s critical to evaluate whether your candidate has a deep, academic understanding and can solve problems theoretically.

After this step, the candidate may be handed back to the CTO who began the process. While hiring teams are encouraged to be thorough, it’s best not to lag. The popularity of the field of AI development means that truly viable candidates are being bombarded with opportunities.

Making Your Decision

Artificial intelligence and machine learning is a competitive field. There is an exceedingly high demand for engineers who are competent in all the areas mentioned throughout this article.

In making your decision, analyze your candidate’s decision-making process whether in person or virtually. Which frameworks is the applicant employing, and why? Are these methods compatible with the way your team approaches problems even if the frameworks themselves are not?

Allow interviewees the space and time to talk through the structure and process of the choices they are making. As one of our experts emphasized, “We like frameworks. Applicants should know why they make the choices they make when using them, based on lower-level knowledge.”

On that note, best of luck hiring developers as you blaze new trails in AI development.

We would like to thank Kevin Bjorke, Senior Software Engineer at Matterport; Jason Laska, Machine Learning Engineer in R&D at Clara Labs; and Steve Macenski, Senior Software Engineer, Robotics and Navigation Lead at Simbe Robotics for their insights as we put together this article. Thanks also to Toptal freelancers Radu Balaban and Cristian Garcia for their invaluable input.

Top AI Engineers are in High Demand.

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