CK-12 Foundation - FlexBooks®
HTTP liveness
realPulse Index
realInsufficient observed signals for a Pulse Index — it needs at least two of four signal families. This product has 1.
Structure
observed attributesAnalyst read
generated from the observed metrics above · no external narrativeCK-12 Foundation - FlexBooks®'s site returned a hard-dead response when we last probed it on Jul 13, 2026, so we mark it inactive. It has fewer than two observed signal families, so no Pulse Index is composed — the evidence strip shows what is and isn’t present. Observed footprint: 10 functional tags. It has no curated competitive-alternative edges yet, so the comparable set below is functional tag-similarity — read it with the confidence flags.
Comparable set
curated alternatives → functional tag-similarity| Company | Basis | Pulse | Families |
|---|---|---|---|
| Kanma - Personal Financefinance | tag-overlap | 8.0 | 1/4 |
| Open Food Factshealth | tag-overlap | 48.2 | 2/4 |
| Open Directoryother | tag-overlap | 8.0 | 1/4 |
| Jasonette Offlinedev-tools | tag-overlap | 8.0 | 1/4 |
| SmartWord - Learn Languages Freeeducation | similar | 0.0 | 1/4 |
| FlashcardXeducation | similar | 8.0 | 1/4 |
| Nulisproductivity | tag-overlap | 8.0 | 1/4 |
| Academic Torrentseducation | similar | 43.9 | 2/4 |
Confidence reflects source and category coherence: curated = an editorially linked alternative; similar = strong functional tag-overlap in the same category; tag-overlap = shared tags only and may be noisy. Pulse is the observed-activity index real; a dash means the comparable has no observed signal families.
Funding & team
not in sourceNo disclosed funding in our sources. Funding data covers only ~1% of the corpus (462 rounds across 79K products), so absence here is unknown, not zero— we don't estimate a number we can't source.