Validate a pixel

Paste a pixel URL from Chrome Network, a postback, a VAST tracker, or a conversion API JSON body. Pixellint checks it against web standards, the vendor's documented parameters, and the IAB consent specs. Everything runs in this tab. Nothing is sent anywhere.

Artifact

Copy the collector URL from the Network tab (filter by facebook.com/tr, googleadservices.com, or the MMP host), or paste the JSON body your backend posts. Ctrl/⌘ Enter validates.

Kind Macros

Try:

Same engine

CLI, CI, agents

The playground is the same validator as the crate, the npm package, and the MCP server. Put the fixtures in CI. Do not paste production HARs into tickets.

cargo install pixellint
npm install pixellint
pixellint validate url 'https://www.facebook.com/tr?ev=Purchase'
pixellint validate json @payload.json --rulepack vendor/meta-conversions-api

GitHub · crates.io · npm · MCP: cargo install pixellint-mcp

Ten reasons

Why bother

Broken pixels return 200. A malformed conversion event is accepted and nothing reports it wrong. You find out at month-end reconciliation, if at all.
Every endpoint wants a different clock. Meta takes seconds, LinkedIn milliseconds, GA4 microseconds, Amplitude milliseconds, PostHog and Braze ISO 8601. Send the wrong unit and the event is accepted, dated 1970.
A purchase with no value reports no revenue. Meta and GA4 both document value and currency as required for purchase events. Neither rejects the event when they are missing.
Hashing goes wrong in both directions. A raw email in user_data is a privacy incident. A hashed IP address makes the event unmatchable. On the wire they look the same.
gdpr_consent=1 passes a format check. It is valid base64. Only decoding the version field shows it carries no consent at all, which is legal exposure behind a green response.
Server-side has no console. Conversion APIs are raw JSON posted from your backend. No network tab, no browser warning, no consent tool to object.
Findings cite the vendor's own documentation. With the URL. That turns "I think the tag is wrong" into a ticket the other team can act on.
It runs before launch. A terminal, CI, an MCP server for agents, an npm package, or this page. Catching a defect at QA costs minutes; catching it after spend costs the campaign.
Vendor rules only fire on vendor endpoints. No noise on an endpoint it does not understand, and no invented rules either. Unknown hosts get attribution, not findings.
One tool, not seven vendor debuggers. Browser pixels, conversion APIs, and the analytics tier, with the same output and the same exit codes across all of them.

Library

Pixels, conversion APIs, consent, MMPs, and launch checklists. All docs.

A pixel is an HTTP request with a job
Pixels
The browser never saw the purchase
CAPI
Hash email and phone. Leave the algorithm as SHA-256.
Identity
Seconds, milliseconds, microseconds, ISO. Pick one.
Time
A TC String is not the letters 1 or true
Consent
The MMP endpoint is a contract, not fire-and-forget
Mobile
timestamp_micros is 16 digits
Analytics
Ship the dictionary before you ship the tag
Launch
fbq plus CAPI, same event_id
Vendor

What it knows

Rulepacks

Deep validation. Each rule carries an evidence level and links to the document it came from. One page per pack.

core
Core Cardinal Rules
vendor/adjust
Adjust S2S events
vendor/adobe-analytics
Adobe Analytics
vendor/amplitude
Amplitude HTTP V2
vendor/appsflyer
AppsFlyer S2S in-app events
vendor/branch
Branch Events API
vendor/braze
Braze user track
vendor/brevo
Brevo Tracker REST events
vendor/floodlight
Google Campaign Manager Floodlight
vendor/google-ads-click-conversions
Google Ads click conversion upload
vendor/google-ads-conversion
Google Ads conversion and remarketing pixel
vendor/google-analytics
Google Analytics 4 Measurement Protocol
vendor/google-analytics-collect
Google Analytics 4 gtag collect
vendor/google-tag-manager
Google Tag Manager and gtag.js
vendor/klaviyo
Klaviyo Create Event
vendor/kochava
Kochava S2S events
vendor/linkedin
LinkedIn image pixel
vendor/linkedin-conversions-api
LinkedIn Conversions API
vendor/meta
Meta Pixel
vendor/meta-conversions-api
Meta Conversions API
vendor/microsoft-uet
Microsoft Advertising UET
vendor/mixpanel
Mixpanel track
vendor/openai
OpenAI Ads image tag
vendor/openai-conversions-api
OpenAI Ads Conversions API
vendor/pinterest
Pinterest Tag
vendor/pinterest-conversions-api
Pinterest Conversions API
vendor/posthog
PostHog capture
vendor/reddit
Reddit Pixel
vendor/reddit-conversions-api
Reddit Conversions API
vendor/rudderstack
RudderStack HTTP and Pixel API
vendor/segment
Segment HTTP Tracking API
vendor/singular
Singular S2S EVENT
vendor/snapchat
Snapchat Conversions API
vendor/tiktok
TikTok Pixel
vendor/tiktok-events-api
TikTok Events API
vendor/x-conversions-api
X conversion API
vendor/yahoo-dot
Yahoo Dot pixel
vendor/yandex-metrica
Yandex Metrica Measurement Protocol

Vendor directory

Endpoint attribution for everything else. One claim per entry: this host belongs to this vendor.