email-validator
post one email, get valid/risk/score back in <50ms. role mailbox, disposable, mx, dead provider — all caught.
$ curl tools.voiddo.com/email-validator/api/v1/email/check
vøiddo
free dev tools
free forever · mit-licensed
2026
tiny tools, zero dollars.
small command-line + browser utilities we use ourselves. no ads, no telemetry. open-source, mit-licensed, free forever. support the studio — Pro $9 lifetime ↓
free forever
0 ads / trackers
MIT every package
npm + cli or browser
used daily in our stack
browser extension spotlight · pricing monitor
pricepulse turns competitor pricing pages into install clicks.
Use pricepulse when a pricing page, plans page, or launch page matters enough to watch. Add the URL once, let the backend re-check it server-side, and get an email diff when the page changes. Free tier covers 5 pages, and the comparison article shows why this beats manual tab babysitting, Visualping-style monitoring, and enterprise CI bloat.
live screenshot · pricing diff viewer
browser extension spotlight · tab export
tabsnap turns open tabs into a shareable install click.
Use tabsnap when a browser session should become a markdown note, a README, plain text, or JSON instead of a private tab pile. One click exports every open tab, strips common tracking parameters, and keeps the whole flow local. If you live in research tabs, this is the portable route.
live screenshot · markdown export popup
free forever
command-line + browser utilities.
npm @v0idd0/*
cronwtf
translate cron expressions into plain english.
$ npm i -g @v0idd0/cronwtf
ctxstuff
pack a folder of files into one LLM-ready prompt.
$ npm i -g @v0idd0/ctxstuff
depcheck
find unused npm / pip / cargo deps without false positives.
$ npm i -g @v0idd0/depcheck
envguard
validate .env files against a schema before deploy.
$ npm i -g @v0idd0/envguard
gitstats
honest contribution stats for any git repo.
$ npm i -g @v0idd0/gitstats
gitwhen
pinpoint when a string, line, or file changed in git history.
$ npm i -g @v0idd0/gitwhen
httpwut
explain HTTP responses with the actual rfc reference.
$ npm i -g @v0idd0/httpwut
jsonyo
json validator + formatter + JMESPath cli.
$ npm i -g @v0idd0/jsonyo
passgen
cryptographically random passwords with entropy meter.
$ npm i -g @v0idd0/passgen
licenseme
audit dependency licenses + flag the bad mix.
$ npm i -g @v0idd0/licenseme
logparse
tail log files + group by error pattern in real time.
$ npm i -g @v0idd0/logparse
promptdiff
diff two LLM prompts and visualize what actually changed.
$ npm i -g @v0idd0/promptdiff
regexlab
explain regex patterns in plain english — token by token.
$ npm i -g @v0idd0/regexlab
secscan
find accidentally-committed credentials in any source tree.
$ npm i -g @v0idd0/secscan
sitescore
check your website’s PageSpeed, SEO, accessibility, and best practices scores in seconds — mobile & desktop.
vøiddo score
5-axis website quality score — clarity, speed, mobile, copywriting, CTAs. results in 30 seconds. embeddable badge drives backlinks. full audit unlocks for $9.
jwtdecode
decode jwt tokens in-browser — header, payload, expiry, algorithm. zero server.
$ npm i -g @v0idd0/jwtdecode
slugmint
i18n url slug generator — cyrillic / greek / hebrew / arabic.
$ npm i -g @v0idd0/slugmint
sslcheck
inspect tls certs for any host:port — expiry, sans, chain.
$ npm i -g @v0idd0/sslcheck
timecheck
convert timestamps between unix, iso, rfc, human — auto-detects.
$ npm i -g @v0idd0/timecheck
tabsnap
export browser sessions or tabs-shaped JSON as markdown / plain / json / readme. if you want the browser version first, jump straight into the install guide.
$ npm i -g @v0idd0/tabsnap
tzdiff
compare timezones side by side. for humans, not crontabs.
$ npm i -g @v0idd0/tzdiff
fakeit
realistic fake test data. seedable, schemable, fast.
$ npm i -g @v0idd0/fakeit
portcheck
see what's listening on your local ports. fast, zero-dep.
$ npm i -g @v0idd0/portcheck
dotdig
dns lookup for humans. formatted output, no flag soup.
$ npm i -g @v0idd0/dotdig
ambiguity-meter
score an incoming message for mixed signals, push-pull, and next-step clarity.
$ npm i -g @v0idd0/ambiguity-meter
soft-yes-or-no
check if a warm, positive reply is a real yes or a soft stall — dating, recruiting, sales, client, family.
$ npm i -g @v0idd0/soft-yes-or-no
replytone
check warmth, clarity, pressure, and urgency in a draft before you send — dating, recruiting, client, sales, workplace.
$ npm i -g @v0idd0/replytone
call-not-text
check if a heated, compressed, or looping thread needs a call — dating, workplace, recruiter, client, support, family.
$ npm i -g @v0idd0/call-not-text
ghost-or-go
decide whether a quiet thread calls for patience, one final ping, or a clean stop — dating, recruiting, client, sales, support, family.
$ npm i -g @v0idd0/ghost-or-go
double-text-risk
score whether another follow-up adds value or looks needy — dating, recruiter, client, support, sales, family, workplace threads.
$ npm i -g @v0idd0/double-text-risk
message-next-step
decide whether to reply now, wait, ask one question, move to a call, or let it go — dating, workplace, recruiter, client, and family threads.
$ npm i -g @v0idd0/message-next-step
boundary-check
does this draft set a clear limit or apologize it away? checks client, recruiter, workplace, family, dating, salary, and scope-creep messages.
$ npm i -g @v0idd0/boundary-check
niche-signal
find competitor pressure in your niche and get wedge-ready opportunities for first-paid experiments.
raincheck-or-run
decide whether to offer one time, hand the next move back, pause, or walk away after a cancellation.
$ npm i -g @v0idd0/raincheck-or-run
interviewprep
paste a job description from LinkedIn, Indeed, Greenhouse, Lever, or Workday — get 5 likely questions, STAR-format prompts, and a role-specific prep brief.
$ npm i -g @v0idd0/interviewprep
tokcount
count tokens and estimate cost across 60+ llm models — gpt-5, claude, gemini, grok, llama, deepseek. no api keys, no telemetry.
$ npm i -g @v0idd0/tokcount
llm-cost
project your monthly llm api spend across 20+ models — gpt-4o, claude, gemini, deepseek, grok, mistral. enter tokens per request × daily volume, see cost table instantly.
salaryneg
generate a ready-to-send salary counter-offer email. current offer, target, argument — get a professional email in seconds. unlock full negotiation pack for $9.
refund-email
generate a polite-but-firm refund request email in seconds. merchant, amount, reason — get a clean letter with order facts in the right order. $9 pro unlocks 2nd-request, final-before-legal, chargeback prep, regulator-cc.
atsresume
paste your resume + the job description — get an ATS keyword match score, missing keywords, and structural flags. 100% in-browser, nothing uploaded. $9 pro unlocks top-50 missing keywords, 12 industry dictionaries, STAR bullet library, cover letter outline.
resignletter
generate a polished resignation letter in seconds. role, last day, reason, tone — get a clean two-weeks notice. $9 pro unlocks 8 scenario variants (immediate, retirement, relocation, counter-offer decline, difficult-manager), conversation script, awkward-reply rebuttals, linkedin announcement, reference-request and handover emails.
product-title
check your product title against amazon, etsy, shopify & ebay rules. character limits, keyword position, policy violations — instant results, all 4 platforms.
randumb
locale-consistent random test data. 58 locales, no russian johns. country ↔ phone prefix ↔ currency ↔ city are coupled. seeded rng. luhn-valid cards.
$ npm i -g @v0idd0/randumb
profile-red-flags
deterministic hinge, bumble, and tinder bio checker for vagueness, pressure, cynicism, inconsistency, and effort. no api calls. same text, same result. coach-ready.
$ npm i -g @v0idd0/profile-red-flags
base64
encode text to base64 or decode base64 strings — standard and url-safe modes. zero server.
urlencode
url-encode strings for query params, path segments, or form data. decode %xx back to text. encodeURIComponent and encodeURI modes.
diff
compare two texts and find every difference instantly. line and character level highlights. zero server — lcs diff runs in the browser.
hash
generate sha-256, sha-512, sha-384 and sha-1 hashes from text or a file. uses native web crypto api — zero server, nothing leaves the browser.
numberbase
convert between decimal, binary, hexadecimal, and octal in real-time. type in any field — all others update instantly. 8/16/32/64-bit padded binary, prefix toggle, browser-only.
wordcount
word count, character count, sentence count, reading time, and word frequency — real-time, zero server, nothing leaves the browser.
color
convert hex, RGB, HSL, HSV, and CSS color formats instantly. pick from the browser color picker or paste any value — browser-only, zero server.
uuid
generate UUID v4, v7, v1, nil, and max UUIDs instantly. bulk generate up to 100 at once — browser-only, zero server, no account needed.
markdown
write markdown and see the rendered HTML preview in real time. supports GFM tables, code blocks, task lists — browser-only, zero server, no account.
csvjson
convert CSV to JSON and JSON to CSV instantly — custom delimiters, pretty print, first-row headers. zero server, nothing leaves the browser.
caseconvert
convert text between camelCase, PascalCase, snake_case, SCREAMING_SNAKE, kebab-case, Title Case, dot.case, and more — instantly, zero server.
lorem
generate lorem ipsum placeholder text by words, sentences, or paragraphs — optional HTML p tags, classic start, instant copy. zero server.
yaml
convert yaml to json and json to yaml instantly. auto-detects input format, validates syntax, pretty-prints output — browser-only, zero server.
epoch
convert unix timestamps to human dates and vice versa. auto-detects seconds vs milliseconds. live epoch clock. shows utc, local, iso 8601, relative time.
sqlfmt
format and beautify sql queries instantly. supports mysql, postgresql, mariadb, sqlite, t-sql, standard sql. indent control. auto-format. browser-only — nothing sent to any server.
htmlfmt
format, beautify, or minify html instantly. indent control, line wrap, comment stripping. beautify and minify modes. browser-only — your code never leaves your machine.
curlfetch
convert curl commands to javascript fetch() calls. handles -X, -H, -d, -u, -b, -L, --max-time, and more. browser-only — your curl command never leaves your machine.
qr
generate qr codes for any url, text, email, phone, or wi-fi credentials. custom size, error correction, and colors. browser-only — nothing sent to any server.
gitignore
generate .gitignore files for any stack — pick languages, frameworks, ides, and os targets. merges 40+ templates, removes duplicates, browser-only. copy or download in one click.
ambiguity-meter
check an incoming message for mixed signals before you reply — for dating, client, recruiter, and workplace threads.
$ npm i -g @v0idd0/ambiguity-meter
boundary-check
set the limit clearly without apologizing it away — for dating, client, family, and workplace conversations.
$ npm i -g @v0idd0/boundary-check
double-text-risk
check if your follow-up message helps or quietly weakens your position — for dating, sales, recruiter, and client threads.
$ npm i -g @v0idd0/double-text-risk
message-next-step
decide whether to reply now, wait, clarify, call, or let it go — for any looping or stalled thread.
$ npm i -g @v0idd0/message-next-step
raincheck-or-run
deterministic check for cancel-or-postpone messages — decide whether to reschedule once, hand it back, or walk away clean.
$ npm i -g @v0idd0/raincheck-or-run
replytone
score one draft on warmth, clarity, pressure, and urgency — for recruiter, client, and dating reply review. no api keys.
$ npm i -g @v0idd0/replytone
soft-yes-or-no
stop chasing the warm maybe — deterministic checker for ambiguous positive replies in dating, sales, and recruiting.
$ npm i -g @v0idd0/soft-yes-or-no
chmod
unix file permission calculator. toggle read/write/execute bits for owner, group, and others — get the octal, symbolic notation, and plain-english meaning. browser-only.
colorcontrast
wcag 2.1 color contrast checker. enter foreground and background colors in hex, rgb, or hsl — see the contrast ratio and aa/aaa pass/fail for normal and large text. browser-only.
semver
semantic version calculator. parse semver strings, bump major/minor/patch/prerelease, compare two versions, and validate against semver.org spec. browser-only.
libraries
copy-paste libraries.
nine reference collections, 125 pages total — built around our most-used tools. each entry has worked examples, edge cases, and a one-click jump into the tool itself.
regex · 25
regex pattern library.
email · URL · phone · IPv4/IPv6 · UUID · semver · JWT · IBAN · Bitcoin · 16 more.
timezone · 25
city pair conversions.
NY↔London · SF↔Tokyo · London↔Mumbai · 22 more — live clocks, DST, business overlap.
cron · 25
cron expression library.
every minute · 5min · hourly · weekday · business hours · monthly · plus Jenkins/Quartz/AWS variants.
dns · 12
DNS record lookups.
MX · SPF · DKIM · DMARC · CAA · SRV · DNSSEC · reverse — with security relevance per record.
json · 10
JMESPath query library.
filter · project · flatten · pipe · multiselect · validate · pretty-print · jq comparison.
http · 8
HTTP RFC reference.
401 vs 403 · 422 · 429 · 503 vs 504 · Cache-Control · CSP · HSTS · CORS — with RFC quotes.
fake · 8
fake test data.
names · emails · IBANs · ISBNs · credit cards (Luhn-valid, NOT real) · phones · addresses · IPs.
slug i18n · 6
URL slug from non-Latin.
Russian Cyrillic · Japanese · Chinese Pinyin · Arabic · Hebrew · Greek — with transliteration tables.
ports · 6
common dev ports.
3000 · 5432 (postgres) · 3306 (mysql) · 8080 · 22 (ssh) — find what's bound, free conflicts.
signal tool spotlight
profile-red-flags for Hinge, Bumble, and Tinder bios.
A deterministic first-pass checker for vague, defensive, pressuring, or quietly hostile dating profiles. Good for match triage, profile rewrites, and coach or matchmaker intake before a deeper tells read.
dating-profile triage
zero API
same text, same result
coach-ready
one loaded case
Deep Dive
$19 once
repeat-use lane
Starter
$14.99/mo
client workflow
Practitioner
$99.99/mo
best fit
dating app triage
Reality-check a bio before attraction talks you into ignoring weak signals.
Reality-check a bio before attraction talks you into ignoring weak signals.
profile rewrites
See whether a profile sounds empty, contempt-heavy, or all standards and no warmth.
See whether a profile sounds empty, contempt-heavy, or all standards and no warmth.
coach and matchmaker intake
Use the free first filter, then move a loaded case into tells when one profile is not enough.
Use the free first filter, then move a loaded case into tells when one profile is not enough.
launch asset spotlight
OG cards from any URL, without opening Figma.
Paste a public page, pull its title, OG image, and favicon, then export a clean 1200×630 card in five styles. Free downloads keep a small made with og.voiddo.com mark. One-time Pro removes it and unlocks logo + CTA overlays for launch posts, docs, and changelog shares.
5 styles
1200×630 png
free with watermark
$9 once for clean exports
best fit
launch posts
Ship a link preview that looks intentional before you spend time on a full campaign graphic.
Ship a link preview that looks intentional before you spend time on a full campaign graphic.
docs and changelogs
Turn repo pages, release notes, or product docs into share-ready OG images in one pass.
Turn repo pages, release notes, or product docs into share-ready OG images in one pass.
small sites without design overhead
Useful when the page exists but the social image still needs a quick, better-looking fallback.
Useful when the page exists but the social image still needs a quick, better-looking fallback.
browser install spotlight
Prompt Vault keeps reusable AI prompts local-first.
If you keep the same launch prompts, support replies, or client prompts in notes, install the browser extension that keeps them in folders, tags, and search instead. Firefox is live now, the public Chromium zip is live now, and the compare page is there if you want the tradeoff in one tab first.
20 free prompts
local storage
public collections in Pro
Firefox live now
best fit
launch prompts
Keep product launches, promo copy, and retry prompts in one reusable place instead of scattering them across docs.
Keep product launches, promo copy, and retry prompts in one reusable place instead of scattering them across docs.
support replies
Save the replies you type over and over so the next help thread starts with something proven.
Save the replies you type over and over so the next help thread starts with something proven.
client work
File prompt variants by client, workflow, or channel, then publish the useful ones as public collection pages.
File prompt variants by client, workflow, or channel, then publish the useful ones as public collection pages.
why free
our paid products buy our time, these tools are bonus.
we built each of these for ourselves first — we needed them on monday morning, the open-source alternatives were either abandoned or did too much. we opened them because there was nothing to lose. they will stay free. if one ever gets bought, we will say so on its readme.
tools.voiddo pro
use these tools daily? $9 lifetime.
one-time · no subscription
All 68 tools stay free forever — Pro is optional. It supports the studio that builds them, gets you early announcements when new tools ship, and gives you a perpetual Pro license on record.
- ✓ Pro license key delivered to your inbox via Paddle receipt
- ✓ early access announcements — new tools before public listing
- ✓ directly funds the next 10+ tools on the roadmap
- ✓ one payment · perpetual license · no recurring fee
get Pro — $9
or stay free forever — no pressure