Utilities

User Agent Parser

Find out which browser, OS and device a User-Agent string belongs to.

  • Runs in your browser
  • Instant results
  • Free, no sign-up
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How to use the User Agent Parser

  1. Your browser's user agent is filled in automatically.
  2. Paste any other User-Agent string or pick an example.
  3. Read the browser, OS, device and the full JSON result.

Frequently asked questions

What is a User-Agent string?

Text that browsers and bots send with each request to identify themselves.

Can user agents be faked?

Yes. Any client can send any string, so never rely on it for security.

Why does Chrome mention Safari and Mozilla?

For historical compatibility, most browsers include older browser names in their user agents.

Practice Python with coding challenges

Solve hands-on problems right in this editor: run the sample tests, submit, and get an AI code review.

All Python challenges
Easy

Average of Three

Average three whole numbers.

You'll learn ArithmeticDivision
BeginnerLearning-pathVariables
Easy

Rectangle Perimeter

Compute the perimeter of a rectangle from its sides.

You'll learn ArithmeticReturn values
BeginnerLearning-pathVariables
Medium

One Generation of a Genetic Algorithm

Breed the next generation of bit strings with tournament selection, single-point crossover and mutation.

You'll learn Genetic algorithmsEvolutionary search
OptimizationSimulationai
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Easy

Epsilon-Greedy Multi-Armed Bandit

Balance exploration and exploitation on a multi-armed bandit with epsilon-greedy action selection.

You'll learn Explore vs exploitBandits
Reinforcement learningaimachine learning
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Easy

Markov Chain State Distribution

Propagate a probability distribution through a Markov chain's transition matrix for a number of steps.

You'll learn Markov chainsProbability
Simulationaimath
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Medium

Value Iteration

Compute how valuable each state of a Markov decision process is by repeatedly applying the Bellman optimality update.

You'll learn Bellman equationMDPs
Reinforcement learningaimachine learning
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Medium

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Apply the Q-learning update to a stream of experiences and watch rewards flow back to earlier states.

You'll learn Q-learningDiscounted rewards
Reinforcement learningaimachine learning
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Medium

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Evaluate a game tree with minimax and alpha-beta pruning, and count how many leaves the search really looks at.

You'll learn Alpha-beta pruningGame search
RecursionTreesai
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Medium

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Pick the perfect tic-tac-toe move by searching the whole game tree with minimax.

You'll learn MinimaxGame trees
Recursionai
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Medium

A* Search on a Weighted Grid

Find the cheapest path across a grid of terrain costs with A*, the search algorithm behind game and robot pathfinding.

You'll learn A* searchHeuristics
GraphsGridsShortest-pathai
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Medium

Temperature and Top-K Sampling

Choose the next token like a language model does: keep the top k logits, apply temperature, and sample.

You'll learn Text generationSampling
aimachine learning
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Hard

Multi-Head Self-Attention

Project the input into queries, keys and values, run attention in several heads in parallel, and combine them.

You'll learn Multi-head attentionMatrix projections
aimachine learning
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