Free Online Developer Tools
Browser-based utilities for developers, learners, writers, and creators. Each tool runs from a crawlable page with supporting notes, FAQs, and related tool links.
Data Structure Visualizers
Browse the full learning path for binary trees, BSTs, heaps, AVL trees, tries, graph traversal, and sorting algorithms.
Algorithm Visualizers
Interactive data-structure and algorithm tools for trees, heaps, tries, graphs, and sorting.
Binary Search Tree Visualizer Visualize binary search tree operations online. Paste an insertion-order array, render the BST, and run search, delete, insert, and traversal steps.Binary Search Visualizer Visualize binary search online. Paste a sorted array, choose exact search or lower bound, and inspect low, high, mid, comparisons, and result index.Prefix Sum Visualizer Visualize prefix sum arrays online. Paste values, build cumulative sums step by step, choose a range, and inspect how range sum queries work.Segment Tree Visualizer Visualize segment tree range sum queries online. Build a tree from an array, inspect overlap decisions, and preview point updates.Fenwick Tree Visualizer Visualize Fenwick tree and Binary Indexed Tree range sums online. Build BIT slots, trace prefix jumps, and preview point updates.Sparse Table Visualizer Visualize sparse table range minimum and maximum queries online. Build power-of-two levels and inspect the two blocks used for RMQ.Interval Tree Visualizer Visualize interval tree overlap search online. Build an augmented BST, inspect subtree max values, and trace interval overlap queries.Merge Intervals Visualizer Visualize merge intervals online. Paste interval pairs, sort by start value, step through overlap checks, and inspect the merged output.Monotonic Stack Visualizer Visualize monotonic stack algorithms online. Paste an array, choose next greater or previous smaller mode, and step through stack pushes, pops, and results.N-Queens Visualizer Visualize the N-Queens backtracking algorithm online. Choose a board size, step through queen placements, rejected attacks, backtracking, and solutions.Minimax Algorithm Visualizer Visualize the minimax algorithm online with Tic-Tac-Toe. Edit a board, score legal moves, inspect game-tree search counts, and find the best move.Binary Tree Visualizer Visualize a binary tree from level-order input. Paste LeetCode-style values, render the tree, and run common traversal orders in your browser.Heap Visualizer Visualize min heap and max heap operations online. Paste an array, build a binary heap, insert values, extract the root, and inspect heap order.AVL Tree Visualizer Visualize AVL tree insertion, search paths, balance factors, and rotations. Paste values and see a self-balancing binary search tree online.Trie Visualizer Build and visualize a trie online. Paste words, search prefixes, autocomplete matches, and inspect how a prefix tree stores strings.Graph BFS DFS Visualizer Visualize graph BFS and DFS traversal online. Paste an edge list, choose a start node, and compare breadth-first and depth-first visit order.Sorting Algorithm Visualizer Visualize sorting algorithms online. Paste an array and step through bubble sort, insertion sort, selection sort, merge sort, or quick sort.Linked List Visualizer Visualize a singly linked list online. Paste values, render nodes and pointers, then insert, delete, search, and traverse the list.Hash Table Visualizer Visualize hash table and hash map operations online. Insert, search, delete, compare chaining with linear probing, and inspect collisions.Stack and Queue Visualizer Visualize stack and queue operations online. Paste values, push, pop, enqueue, dequeue, peek, and compare LIFO vs FIFO behavior.Dijkstra Algorithm Visualizer Visualize Dijkstra shortest path search online. Paste weighted graph edges, choose start and target nodes, and step through distance updates.A Star Pathfinding Visualizer Visualize A* pathfinding online. Paste a grid with walls, choose a heuristic, and step through open set, closed set, g, h, f, and final path.Bellman Ford Visualizer Visualize Bellman-Ford shortest paths online. Paste directed weighted edges, keep negative weights, and step through relaxation and cycle checks.Floyd Warshall Visualizer Visualize Floyd-Warshall all-pairs shortest paths online. Paste directed weighted edges and step through the distance matrix updates.Kruskal Algorithm Visualizer Visualize Kruskal MST construction online. Paste weighted edges, sort by weight, and step through union-find cycle checks.Prim Algorithm Visualizer Visualize Prim minimum spanning tree construction online. Paste weighted edges, choose a start node, and step through frontier edge choices.KMP String Matching Visualizer Visualize KMP string matching online. Enter text and pattern, build the LPS table, and step through comparisons, fallbacks, and match indexes.Rabin Karp Visualizer Visualize Rabin-Karp string matching online. Enter text and pattern, adjust base and modulus, then step through rolling hash checks.Z Algorithm Visualizer Visualize the Z Algorithm online. Enter text and pattern, build the combined string, inspect Z-box reuse, and find pattern match indexes.Edit Distance Visualizer Visualize edit distance online. Enter two strings, fill the Levenshtein DP table, and inspect insert, delete, substitute, and match decisions.Longest Common Subsequence Visualizer Visualize longest common subsequence dynamic programming online. Enter two strings, fill the LCS table, and backtrack one subsequence.Coin Change DP Visualizer Visualize coin change dynamic programming online. Enter coin values and a target amount, then step through minimum-coin DP updates.Longest Increasing Subsequence Visualizer Visualize longest increasing subsequence dynamic programming online. Paste numbers, compare prior indexes, and backtrack one LIS.Fibonacci DP Visualizer Visualize Fibonacci dynamic programming online. Choose n, fill the tabulation table, and inspect how each value reuses the previous two answers.LRU Cache Visualizer Visualize LRU cache operations online. Set capacity, run get and put operations, inspect the hash map, recency list, hits, misses, and evictions.Union Find Visualizer Visualize union find and disjoint set operations online. Create nodes, union sets, find roots, and inspect parent links, ranks, and connected components.Topological Sort Visualizer Visualize topological sorting online. Paste directed edges, run Kahn or DFS order, inspect in-degrees, queue updates, and cycle detection.Recursion Tree Visualizer Visualize recursion trees and call stacks online. Choose factorial, Fibonacci, or binary recursion and inspect calls, returns, depth, and stack frames.Knapsack DP Visualizer Visualize 0/1 knapsack dynamic programming online. Paste item weights and values, set capacity, inspect the DP table, and recover selected items.Red Black Tree Visualizer Visualize red black tree insertion online. Paste values, inspect node colors, rotations, recoloring, black height, and search paths.Sliding Window Visualizer Visualize sliding window algorithms online. Paste an array, run fixed-size or variable-size windows, and inspect left, right, sum, and best result.Two Pointers Visualizer Visualize two pointer algorithms online. Paste values, run sorted pair sum or container area, and inspect left and right pointer movement.Backtracking Visualizer Visualize backtracking online. Generate subsets or permutations, inspect the recursion stack, decision tree, current path, and completed results.Matrix Traversal Visualizer Visualize matrix traversal online. Paste a grid, run spiral order or grid BFS, and inspect visited cells, frontier cells, and traversal order.
Text Tools
Utilities for comparing and measuring written text directly in your browser.
Text Comparison Tool Compare two blocks of text online and review added, removed, or changed words with a clear side-by-side difference view.Word Counter Free online word counter tool. Quickly count words in any text or document. Useful for writers, students, and content creators to stay within word limits.
Developer Utilities
Format, validate, convert, and inspect common developer data formats locally.
JSON Formatter Format, validate, minify, and inspect JSON online. Paste JSON, catch syntax errors, copy formatted output, and review a tree-style JSON viewer.Regex Tester Test JavaScript regular expressions online. Enter a pattern, choose flags, inspect matches and capture groups, and preview replacements in your browser.Base64 Encoder Decoder Encode and decode Base64 text online. Convert UTF-8 text to Base64, decode Base64 back to text, and switch to URL-safe Base64 locally in your browser.Unix Timestamp Converter Convert Unix timestamps to readable dates online. Switch between seconds and milliseconds, view UTC and local time, and convert dates back to Unix time.UUID Generator Generate random UUID v4 values online. Create one or many UUIDs, switch between hyphenated or compact formats, and validate pasted UUIDs locally.Cron Expression Generator Generate cron expressions online. Build common schedules, edit custom cron fields, validate syntax, and preview upcoming run times locally.
Downloader Tools
Browser-based helpers for media link tasks.
Instagram Reels Downloader Easily download Instagram Reels videos online for free with our fast and safe downloader. Save high-quality Reels in MP4 format without watermark or login.YouTube Video Downloader Download YouTube videos in high quality including 1080p, 2160p, 2k, 4k, 8k without installing any software. Try our free online YouTube video downloader.