Decodable library + on-demand generation

Every student gets a book that matches the exact lesson they're on.

Schools tell us the same thing: their library can't keep up with where each student actually is in scope and sequence. We solve that three ways — a pre-built library tagged against the leading curricula's lesson orders, on-demand personalized decodables generated live for the exact lesson, and Hi-Lo decodables for older readers that don't break the phonics constraint.

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What's a decodable, exactly? →

How we do it

Three ways into a lesson-aligned book — the library is one of them.

Tier 1 · Pre-built library

2,000+ decodables, cross-tagged to the leading curricula's scope and sequences.

Every decodable in the in-app library is tagged with the phonics patterns it uses, the heart words it requires, the grade band, and the curriculum lessons it satisfies. Pick a curriculum, pick a lesson — the library returns the exact books that fit, not a generic level equivalency. (Decodables are the lesson-matched core of the broader Discover Library, which also includes Hi-Lo decodables, leveled fiction and non-fiction for reading beyond the phonics constraint, read-along videos, and songs.)

Tagged against the lesson order of UFLI, Wilson, Amplify CKLA, IMSE, LMW, Storytime AI
Cross-references heart words required, target phonics patterns, grade band
Books surface in the student's journey only after the lesson covers their patterns
Teachers, parents, and students see the same lesson-matched view

Tier 2 · On-demand personalized decodables

Generated live for the specific lesson your student needs.

When the library doesn't have a book matched to the exact lesson — or when a student needs more practice on one specific pattern — Storytime generates a brand-new decodable in seconds. Same curriculum scope, same heart-word constraints, same decodability standard.

Generated against the active curriculum's scope and sequence
Phonics patterns capped at what the lesson has actually taught
Teacher controls characters, image style, plot prompt, and length
Narrated audio and illustrations generated alongside the text
Honest decodability percentage shown — not relaxed to make a 'good number'

Tier 3 · On-demand Hi-Lo decodables

Age-respectful stories with the same phonics control for older striving readers.

A 4th-grade reader on short-vowel patterns shouldn't have to open a book about a cat on a mat. Hi-Lo decodables keep the same scope-and-sequence precision — plot, setting, theme, and tone are calibrated for an older audience without breaking the phonics constraint.

Same curriculum scope-and-sequence anchoring as Tier 2
Plot, setting, theme, and tone calibrated for grades 3-12
Lesson-gated — student must be far enough through the scope for an older arc to work
Hi-Lo badge surfaces in the library for clarity
Decodability percentage scored against the same standard as K-2 decodables

Under the hood

Six dimensions per book. Not one.

"Decodable Level B" is one dimension. Every book in Storytime carries six — so the system can match a student's exact phonics inventory, not just their grade. This is what makes curriculum-specific alignment work.

Target phonics pattern: Closed syllables, CVCe, r-controlled, diphthongs, schwa, prefixes/suffixes, …
Heart words required: Every irregular high-frequency word the student must already know to read the book unaided.
Curriculum lesson alignment: Cross-tagged against the lesson order of the supported curricula — UFLI L42, Wilson Step 2.3, etc.
Decodability percentage: Honestly computed from the student's accumulated phonics inventory at the chosen lesson.
Grade band: K, 1, 2, 3-5, 6-8, 9-12 — surfaced separately from phonics scope so older students get dignity.
Story length: 7-paragraph standard, 14-paragraph extended, 21-paragraph long-form for older readers.

Why this matters

"Level equivalency" doesn't solve the problem schools have.

Two students can be in the same grade and at the same nominal decodable level and still need completely different books. One needs more /sh/ practice. The other moved past /sh/ and is on closed-syllable two-syllable words. A level tag can't disambiguate that.

Typical decodable library

Static catalog. Books are roughly level-tagged (Decodable Level B, Level 2, etc.) but not mapped to specific curriculum lessons. If a student needs practice on /sh/ before their book bank moves to /th/, you're out of luck unless the catalog happens to have a /sh/-only title.

Storytime

Dynamic catalog. Pre-built library is cross-tagged against curriculum lessons, not just levels. When the library doesn't have an exact match, generation creates one inside the same scope. Hi-Lo extends this to older audiences without breaking the phonics constraint.

The bargain we keep with teachers.

Whether a book comes from the pre-built library or is generated on demand, three things stay constant: the phonics scope visible to teachers, the heart-word inventory honest about what the student must already know, and the decodability percentage computed honestly — not relaxed to flatter the catalog. Lesson alignment is a contract, not a marketing claim.

Generation is lesson-gated. Students cannot generate a book outside the eligible scope-and-sequence range for their current lesson. The teacher's curriculum stays the source of truth.

About the authors

Written and edited by the Storytime AI founding team.

Brian Carlson

Co-founder & CEO

Co-founder and CEO of Storytime AI. Leads the company from Baltimore, building a literacy platform that meets every reader where they are — anchored to the Science of Reading.

Scott Quinlan

Co-founder & CTO

Co-founder and CTO of Storytime AI. Owns engineering, product infrastructure, and the agentic growth pipeline — from the platform's AI generation engine to the structured-literacy content surface district leaders evaluate.

Kate Dwyer

Co-founder & CMO

Co-founder and Chief Marketing Officer at Storytime AI. Translates Science-of-Reading research and product capability into language teachers, parents, and district leaders can act on. Based in the Washington DC–Baltimore area.

Generate a book matched to your student's exact lesson this period.

Pick the curriculum, pick the lesson, pick the audience. You'll have a decodable book in the library before the bell rings.

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