Now 46 apps and counting
Utility apps
your AI
assistant can
actually trust
Each app does one job with deterministic evidence — validating a file, checking a feed, measuring a site — so the answer comes from a real engine, not a guess. Use them right here in the browser or from any MCP-compatible assistant, all on one free account.
A real validation report, exactly as the engine returned it
How it works
Three steps from question to evidence.
- 1 Pick the app for the jobBrowse the directory — every app page says exactly what it checks, and the app itself is right there at the top of the page, ready to run.
- 2 Use it anywhereRun it in the browser, or connect through ChatGPT and any MCP-compatible assistant — one free account pools your usage across every surface.
- 3 Get evidence, not guessesResults come from pinned validation engines with honest scope notes, the same output no matter where you call from.
The apps
Every app is a narrow, honest tool with a live web version on its page — try any of them right now, no account needed.
- 3D Asset CheckValidate a glTF asset before it shipsDeveloper Tools · Design
- Adaptive Stream CheckCheck live HLS and DASH delivery in chatDeveloper Tools · Productivity
- Ads.txt CheckValidate ads.txt and cross-check sellers.json in chatBusiness · Developer Tools
- Auth Discovery CheckCheck an OIDC/OAuth issuer's discovery documents in chatDeveloper Tools · Security
- BIM Model CheckValidate a hosted IFC building model against the IFC schema, EXPRESS where-rules, and buildingSMART normative rules with ifcopenshell, with the exact violated rule and offending instance — real conformance validation, not a STEP-text parseDeveloper Tools · Productivity
- Calendar File CheckCheck an .ics calendar feed before you share itProductivity · Developer Tools
- Caption File CheckCheck subtitle and caption files in chatMedia · Productivity
- Catalog Feed CheckCheck shopping product feeds in chatBusiness · Productivity
- Croissant Dataset CheckValidate a hosted Croissant ML-dataset metadata doc with the real mlcroissant structure-graph engine, plus a bounded distribution-reachability probeDeveloper Tools · Productivity
- CSAF Advisory CheckCheck a CSAF 2.0 security advisory before you publish itDeveloper Tools · Security
- CWL Workflow CheckValidate a hosted Common Workflow Language document with the reference cwltool --validate engine — real SALAD reference resolution and cross-step type wiring, not a YAML syntax parseDeveloper Tools · Productivity
- Data Catalog CheckCheck a hosted DCAT-AP open-data catalog against the official SHACL shapes, with exact shape-and-focus-node evidenceDeveloper Tools · Productivity
- Data Package CheckValidate a hosted Data Package descriptor AND its referenced remote data rows — types, constraints, primary keys, and cross-resource foreign keys the sandbox can't fetchDeveloper Tools · Productivity
- Deep Link CheckCheck universal-link and App-Links config in chatDeveloper Tools · Productivity
- E-Invoice CheckValidate a hosted or pasted EU e-invoice against EN 16931 and the KoSIT Schematron business rules — hundreds of rules beyond the XSD, with exact rule-ID and element evidenceDeveloper Tools · Productivity
- Ebook Accessibility CheckRun DAISY Ace on a hosted EPUB and see the WCAG and EPUB-accessibility issues before you sell it in the EUDeveloper Tools · Productivity
- Ebook File CheckCheck an EPUB against the spec before uploadProductivity · Developer Tools
- Fediverse Actor CheckResolve a @user@host handle through WebFinger to its ActivityPub actor and check the negotiated discovery chain in chatDeveloper Tools · Social Networking
- FHIR Conformance CheckCheck a hosted or pasted public FHIR artifact against its declared profile with the official HL7 validator, with exact StructureDefinition, invariant, and binding evidenceDeveloper Tools · Productivity
- Font CheckupInspect a font binary before releaseDesign · Developer Tools
- GEDCOM File CheckValidate a hosted GEDCOM 7 genealogy file against the GEDCOM-registries corpus with the reference GedValidate engine, with exact rule-class evidence — real corpus validation, not a line-grammar parseDeveloper Tools · Productivity
- Geospatial Catalog CheckTraverse and validate a hosted STAC catalog's whole link tree before you publish itDeveloper Tools · Productivity
- GTFS Feed CheckCheck a GTFS transit feed against the spec, with exact notice-code evidence, before you republishDeveloper Tools · Productivity
- JATS Article CheckCheck a hosted or pasted JATS XML article against the JATS4R reuse and quality rules with the real Schematron engine, with exact rule-code evidenceDeveloper Tools · Productivity
- Manifest CheckCheck web app manifest installability in chatDeveloper Tools · Productivity
- MEI Encoding CheckCheck a hosted or pasted public MEI music encoding against BOTH its RelaxNG grammar and the beyond-schema XPath2 musical-semantic Schematron layer, with exact rule and location evidenceDeveloper Tools · Education
- Multilingual Site CheckCheck locale pages and hreflang in chatDeveloper Tools · Productivity
- netCDF CF CheckCheck a hosted netCDF file against the CF Metadata Conventions from a public URL, with per-check rule evidence and no uploadDeveloper Tools · Productivity
- NeTEx Dataset CheckCheck a hosted NeTEx transit dataset against the CEN schema and the Nordic/EPIP profile rules, with exact rule-and-element evidenceDeveloper Tools · Productivity
- OCDS Package CheckCheck a hosted OCDS release or record package against the standard, its declared extensions, and the lib-cove additional checks, with exact check-and-location evidenceDeveloper Tools · Productivity
- Package CheckupInspect an npm package before you install itDeveloper Tools · Productivity
- PDF CheckupCheck a PDF standard before deliveryProductivity · Developer Tools
- Podcast Feed CheckCheck podcast feeds and episodes in chatDeveloper Tools · Productivity
- Product Link Resolver CheckCheck a product 2D-barcode resolver before you ship itDeveloper Tools · Productivity
- SBOM CheckCheck an SBOM document before you ship itDeveloper Tools · Productivity
- SDMX Data CheckCheck a public SDMX-ML data message against its Data Structure Definition and codelists — with live-fetched codelist-membership evidence a plain XSD check can't give youDeveloper Tools · Productivity
- STIX Bundle CheckCheck a hosted STIX 2.1 threat-intel bundle against the OASIS validator, with exact object, reference, and pattern evidenceDeveloper Tools · Productivity
- Structure File CheckValidate a hosted PDBx/mmCIF structure against the wwPDB DDL2 dictionary with gemmi, with exact category-and-item evidence — real dictionary validation, not a syntax parseDeveloper Tools · Productivity
- TEI Document CheckCheck a hosted or pasted public TEI edition against BOTH its RNG grammar and the beyond-schema XPath2 Schematron layer, with exact rule and location evidenceDeveloper Tools · Education
- Thing Description CheckValidate a hosted or pasted W3C WoT Thing Description against both the JSON Schema and the beyond-schema assertions ajv alone cannot check, in chatDeveloper Tools · Productivity
- Track CheckupMeasure an audio master before releaseMusic · Productivity
- Tracker CheckupSee what a website tracks during a real visitProductivity · Developer Tools
- Variant File CheckRun EBI's real vcf_validator conformance engine on a hosted VCF, with exact rule-and-line evidence — not just a parseDeveloper Tools · Productivity
- VOTable CheckValidate a hosted astronomy VOTable against astropy's ~80-code IVOA conformance corpus with exact line-and-code evidence — real conformance validation, not an XSD or well-formedness parseDeveloper Tools · Productivity
- Web CheckupFull website health checks in chatDeveloper Tools · Productivity
- XBRL Filing CheckCheck a public XBRL or ESEF filing against the taxonomy and disclosure-system rules, with exact rule-code evidenceDeveloper Tools · Productivity
Simple, usage-based, free to start
No feature gates anywhere — every plan gets every app and every tool, pooled across the web apps and every connected assistant. Plans only change how much you can run.
Free
One free account, one pool that follows you across every app and every assistant.
$0forever
Create your free accountIncluded
750 units every month
Pooled across web + MCP surfaces
Usage dashboard
Optional launch updates
Pro
For steady professional use — a serious monthly pool and a higher burst ceiling. Launching soon.
$19/moper month
Get notified at launchIncluded
25,000 units every month
Higher per-minute burst ceiling
On-demand top-ups at member pricing
Scale
For heavy workloads and teams that lean on the validators every day. Launching soon.
$79/moper month
Get notified at launchIncluded
125,000 units every month
Highest burst ceiling
Priority support
FAQ
Common questions
The short version of what these apps are and are not.
01What do these apps actually do?
Each one runs a real, pinned validation or measurement engine over something you point it at — a file, a feed, a site, a dataset — and reports the engine's findings with clear scope. No app fabricates results or offers judgment beyond what it measured.
02What does it cost?
Every app is free: a daily guest allowance with no account, and a bigger monthly pool on a free account. Paid tiers with larger pools launch later — they only ever raise limits, they never lock features.
03Do I need an account?
No. Every app works without one. A free account raises your allowance and pools it across the web apps and every assistant you connect — that's the whole difference.
04What are usage units?
Every run costs a few compute units scaled to what it really costs us to run — a quick parse is 1, a sandboxed engine 5, a heavy full-browser job 25. Your allowance is one pool of units across all apps.