UI Text CDN / API

Access your localized UI Text strings from anywhere via a globally distributed API. Use this to hydrate your app UI at runtime or to prebuild locale bundles.

Authentication

Your project API key authenticates requests to the UI Text API. You can rotate it any time from your project settings. The key only grants READ access to UI Text translations for your project. It cannot modify data.

Send the key in one of two ways:

Query param: ?auth=<API_KEY>
Header: X-Auth-Apptonomy: <API_KEY>

Endpoint

The endpoint is specific to each project.

GET https://api.apptonomy.ai/u/v1/{projectId}/uitext

Where {projectId} is your Apptonomy project ID.

Request parameters

lang (required): Two- or multi-part language code indicating the desired locale, e.g. en, fr, es-419, zh-CN.
- Provide via query string: ?lang=<language-code>
- See supported language lists for the stores: App Store · Google Play
setid (optional): UI Text Translation Set ID to fetch.
- If omitted, the most recently created translation set is returned
- Provide via query string: ?setid=<set-id>
stringid (optional): Request a single string by its ID.
- If provided, the response is a JSON object containing only that string
- Provide via query string: ?stringid=<string-id>

Examples

cURL — header auth

curl -s \
  -H "X-Auth-Apptonomy: $UITEXT_API_KEY" \
  "https://api.apptonomy.ai/u/v1/${PROJECT_ID}/uitext?lang=en"

cURL — query param auth

curl -s \
  "https://api.apptonomy.ai/u/v1/${PROJECT_ID}/uitext?lang=fr&auth=${UITEXT_API_KEY}"

JavaScript (fetch)

const url = `https://api.apptonomy.ai/u/v1/${PROJECT_ID}/uitext?lang=es-419`
const res = await fetch(url, { headers: { 'X-Auth-Apptonomy': API_KEY } })
if (!res.ok) throw new Error(`Request failed: ${res.status}`)
const translations = await res.json()
// translations['string_0'] → "..."

Single string

curl -s \
  -H "X-Auth-Apptonomy: $UITEXT_API_KEY" \
  "https://api.apptonomy.ai/u/v1/${PROJECT_ID}/uitext?lang=ja&stringid=string_0"

Response

The response is JSON.

Full set (default)

{
  "string_0": "Welcome",
  "string_1": "Create account",
  "string_2": "Continue",
  "cta_primary": "Start"
}

Single string (when `stringid` is provided)

{ "string_0": "ようこそ" }

Status codes

200: Success
400: Missing or invalid parameters (e.g. lang)
401: Invalid or missing API key
404: Project, set, or string not found
429: Rate limit exceeded (includes Retry-After header)
5xx: Transient service error

Deployment

Performance: The API is deployed on Cloudflare Workers with translations cached in Cloudflare KV for fast global access.
Caching: Responses are served from edge locations; you may additionally cache responses in your app to reduce round-trips.
Rate limits: Sensible limits protect the service. On limit exceed, a 429 is returned with a Retry-After header. Implement exponential backoff or respect the retry hint.

Tips

Prefer header-based auth in public URLs to avoid leaking query params in logs.
When using stringid, consider batching string IDs in one request by omitting stringid and filtering client-side if you need many strings.
Keep your API key secret in server-side environments where possible; client-side usage is supported but be mindful of distribution.