Fast, free tools for developers and ad-tech engineers.
75 focused utilities — format JSON, decode JWTs, test a VAST tag in a real IMA player, receive webhooks and OpenRTB bid requests live, validate ads.txt against sellers.json, and more.
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JSON Formatter
Beautify, minify, sort, query and repair JSON with a tree view and copy-as code export.
Base64 Encode / Decode
Encode text, hex or any file to Base64 (and Base32, Base58) and decode back — with data URIs and image preview.
JWT Decoder
Decode, verify (HS/RS/ES/PS, JWKS) and sign JWTs
Password Generator
Strong random passwords, diceware passphrases, PINs and pronounceable codes with crack-time estimates.
UUID Generator & Inspector
Generate UUID v1/v3/v4/v5/v6/v7, ULIDs and nanoids in bulk, inspect any UUID, and validate lists.
Regex Tester
Test regular expressions with in-place highlighting, a token-by-token explainer and code export.
Color Converter
Convert any CSS colour between HEX, RGB, HSL, HWB, LAB, LCH, OKLCH and P3, with contrast checks and ramps.
CSS Gradient Generator
Design linear, radial and conic gradients with draggable stops, layers and Tailwind, CSS or SVG output.
VAST Inspector
Fetch or paste VAST 2/3/4 tags — follow wrapper chains, validate, ping pixels, and play media files.
VAST Ad Tester (IMA Player)
Play any VAST or VMAP tag in a real Google IMA player and watch every SDK event, error and timing.
OpenRTB Inspector
Validate & annotate OpenRTB 2.6 BidRequest and BidResponse JSON.
RTB Bidder Sandbox
A live OpenRTB bidder endpoint that captures every bid request and answers with bids, no-bids, custom templates or timeouts.
Categories
Browse by type
JSON Tools
11 toolsFormat, validate, convert, and explore JSON data.
Text Tools
11 toolsCount, transform, compare, and manipulate text.
Crypto & Auth
9 toolsHashes, tokens, passwords, and encoding utilities.
CSS & Design
10 toolsColors, gradients, shadows, and visual generators.
Converters
17 toolsSwitch between formats, bases, units, and encodings.
Developer Tools
43 toolsRegex, cron, HTTP references, and everyday dev helpers.
Ad-tech & Video
14 toolsVAST, VMAP, IMA player, consent strings, ads.txt, HLS playlists.
RTB & Programmatic
9 toolsBidder sandbox, OpenRTB builder, bid response inspector, supply-chain checks.
Programmatic & video
Built for ad-tech engineers
Live endpoints and real players, not just parsers: point an exchange at a sandbox bidder, play a VAST tag through the Google IMA SDK, and verify supply chains from a domain name.
RTB Bidder Sandbox
A live OpenRTB bidder endpoint that captures every bid request and answers with bids, no-bids, custom templates or timeouts.
VAST Ad Tester (IMA Player)
Play any VAST or VMAP tag in a real Google IMA player and watch every SDK event, error and timing.
OpenRTB Request Builder
Build OpenRTB 2.6 bid requests with a form or JSON, then send them to any bidder and inspect the response.
sellers.json Inspector
Fetch any exchange's sellers.json by domain, validate it against the IAB spec, cross-check a publisher's ads.txt against it, and resolve OpenRTB supply chains.
VAST Inspector
Fetch or paste VAST 2/3/4 tags — follow wrapper chains, validate, ping pixels, and play media files.
IAB TCF Consent Decoder
Decode TCF v2.2 consent strings with vendor names from the Global Vendor List, a purpose × vendor matrix and an encoder.
ads.txt / app-ads.txt Validator
Fetch any domain's ads.txt or app-ads.txt, validate it against the IAB 1.1 spec, follow SUBDOMAIN pointers, and cross-check every line against exchange sellers.json files.
Bid Response Inspector
Decode an OpenRTB BidResponse: bids, macros, no-bid reasons, creative preview and win/billing notice firing.
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Tools run in your browser. Relay-backed tools keep data in memory only and delete it within an hour of inactivity.
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Input is processed as you type, with keyboard shortcuts, samples and fullscreen on every tool.
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