An interactive, 100% client-side tool for designing and teaching how to model your data into a NoSQL database, initially with DynamoDB as the destination. Write your model as plain text, watch it project into the base table and its indexes, step through writes, see the estimated cost of each one, and query it all in the browser. The data is yours! Your model is never sent to a server and is stored nowhere but your browser tab (see Privacy).
Most people learn DynamoDB data modeling from static blog diagrams. Here you load a model and watch it work: the GSI reprojects, the sparse index skips a row, a key change costs a
DELETE+PUT, aSCANreads the whole table.
- The text is the model. A tiny, readable DSL, diffable in a PR, editable in vim, pasteable in Slack. The format is the sharing mechanism.
- Define your access patterns up-front. Declare what your design must serve
with
@ap, and the app runs each one against the model, so you see at a glance which patterns are covered and which are still gaps. - It teaches core datamodelling techniques: GSI overloading, sparse indexes,
the reindex cost of a key change, transactional (2×) writes, projection modes,
native multi-key GSIs, conditional writes (
@if) and what a failed condition still costs you, and why a filter doesn't reduce a query's read cost. - Guided tours built in! Most of the DynamoDB examples are plain text, and even if there is nothing wrong with that, I always believed it is easier to see it in a step-by-step movie. The Learn menu plays short narrated scenarios, from "how the editor works" to GSI overloading, sparse indexes, atomic key changes, and conditional writes.
If you want AWS's official tooling for DynamoDB, use NoSQL Workbench: that is what AWS recommends, and it's a great tool. Keyway is not trying to compete with it.
I built Keyway because I wanted something those tools generally don't offer: a text-first model you can diff and share as a link, stepped playback that shows the estimated cost of each write, access-pattern coverage that actually runs your queries, and narrated tours that teach the mechanics, all in the browser with nothing to install. Different goals; use whichever fits.
Your model never leaves your browser. There is no backend. The app makes no
network calls with your data: your model lives in the tab (it isn't even saved to
localStorage), and shared links carry the model in the URL fragment (#m=…),
which browsers never send to a server. You can create your data model without
anything leaving your machine.
The one thing I count is anonymous page-views (via GoatCounter), so I can tell roughly how many people find Keyway useful. No cookies, no personal data, and no IP addresses or identifiers are stored. You can't be tracked or profiled. Only the fact that a page loaded (plus the referring site, and a few anonymous events — like which example or learn path was opened, so I can tell which ones people find useful) is counted, never anything you type.
You don't have to take my word for any of this. It's a static site: open your DevTools Network tab and watch. You can even see the numbers I see — the GoatCounter dashboard is public. Or read the exact lines:
- Your model is never transmitted. It's held in the URL fragment (
#m=…), which the browser strips before it makes any request. Seesrc/model/share.ts. - We send only the page path, to one place. In
index.htmlthe page-view is sent by our own line,goatcounter.count({ path: location.pathname }), so the query string and the#m=…model are never included. The single request goes tokeyway.goatcounter.com/count; on the live site you can watch it in the Network tab (on localhost nothing loads and nothing is sent). - The in-app events are one tiny, guarded call with an event name and nothing
else — e.g.
example:users-ordersortour:getting-started, a slugified label built from the item's title, never your model. Seesrc/analytics.ts. - No IPs or cookies are stored: that's GoatCounter's design, and both its server and the count.js client are open source, so you can read exactly what runs.
npm install
npm run dev # http://localhost:5173
npm test # the engine's unit tests
npm run build # static site into dist/It's a static single-page app, so GitHub Pages is ideal and free. This repo publishes to https://tebanieo.github.io/Keyway/.
- Push this repo to GitHub.
- Settings → Pages → Build and deployment → Source = "GitHub Actions".
- The included workflow (
.github/workflows/deploy.yml) builds the app and the reference docs on every push tomain, serving the docs at/Keyway/docs/alongside the app. Vite'sbase: "./"keeps the app's assets relative, and the VitePressbaseis already set to/Keyway/docs/for this repo.
- Link: the share button copies a URL with the whole model in it.
- Example: pick one from the examples menu.
- Copy-paste: the model is just text; paste it anywhere. Always works.
- In the app: the Learn menu plays guided, narrated tours (start with "Getting Started" and "How to Model"), and the Docs link opens the reference.
- Reference manual: a VitePress site under
docs/(the DSL grammar, the editor, filters, the cost model, access patterns, sharing) that publishes at https://tebanieo.github.io/Keyway/docs/. Run it locally withnpm run docs:dev.
The single most useful thing you can do is tell me how it felt to use. Was something confusing? Did a cost number surprise you? Did a tour land, or fall flat? Open a feedback note, or just say what's on your mind. That shapes Keyway more than anything else.
Beyond that, both of these are welcome:
- Feature requests. A sentence on what you'd want, and why, is plenty. Start one here.
- Pull requests, for a bug fix, a docs tweak, or a new example. See Development for the setup. Keep them small where you can; for anything bigger, open an issue first so we can talk it through.
The easiest PR is a new example: append a { name, description, dsl } entry
to src/model/examples.ts. A test checks that every example parses, so a broken
one fails CI.
npm run dev # Vite dev server
npm test # Vitest engine + model tests
npm run lint # ESLint (flat config)
npm run format # PrettierA Lefthook pre-commit hook runs format, lint, typecheck, and the full test
suite on every commit; npm install wires it up automatically (no Python
needed). The engine lives in src/engine/ (pure, DOM-free), the DSL and model
logic in src/model/, and the React UI in src/components/.
@table AppTable pk=PK sk=SK # optional; base keys default to PK/SK
@gsi GSI1 pk=GSI1PK sk=GSI1SK # declare an index (one pane per @gsi)
@gsi ByRegion pk=tenant,region sk=status,date # native multi-key GSI
@ap List a user's orders -> AppTable PK=USER#1 SK begins_with ORDER# # a requirement
@ap Look up a user by email -> GSI1 GSI1PK=EMAIL#ada@x.io # the app runs it + grades coverage
u1: PK=USER#1 SK=PROFILE name=Ada _type=user # label: attrs (label = stable id)
u1: PK=USER#1 SK=PROFILE name=Ada Lovelace # same label = update
o1: PK=USER#2 SK=PROFILE # a new PK = atomic key change
u2: PK=USER#3 SK=PROFILE @if attribute_not_exists(PK) # conditional write (create-only)
delete o1 # remove an item
@apdeclares an access pattern (a requirement); the app runs it against the model and shows which patterns are served and which aren't.@if, as the last clause on a put/delete, is a conditional write: it applies only if the condition holds, else it's rejected (and a failed check still costs)._typegroups items into entities the editor can scaffold and backfill.- Comments (
#) are free text; a comment directly above a line narrates that step.
Created by Esteban Serna with ♥. Built with React · Vite · CodeMirror, and developed with the help of Claude Code. MIT-licensed: use it, fork it, teach with it, or better yet, use the version already deployed at https://tebanieo.github.io/Keyway/.
Keyway is a personal project. The opinions and views expressed in this repository and in the tool are my own and do not represent those of my employer, Amazon Web Services (AWS), or Amazon.com, Inc. Keyway is not an official AWS product and is not affiliated with, endorsed by, or supported by AWS or Amazon.
Amazon DynamoDB, AWS, and NoSQL Workbench are trademarks of Amazon.com, Inc. or its affiliates.