AltText.ai API

Name: AltText.ai API API
Brand: AltText.ai API
Availability: InStock

★ Only Publicly Available SpecAI/MLVisionapiKey10 EndpointsREST

For Agents

Generate accessibility-grade alt text for images, including bulk and page-scrape modes, through 10 X-API-Key endpoints. Useful for agents adding alt text to CMS libraries, e-commerce catalogues, and email assets.

Quickstart

Get started with AltText.ai API in minutes using your preferred integration method.

# Add to your MCP client config (Claude Desktop, Cursor, Windsurf)
{
  "jentic": {
    "url": "https://api.jentic.com/mcp",
    "auth": "oauth"
  }
}

# Then ask your agent:
"generate alt text for an image"

# → Jentic returns the GET /events tool with parameter schema, agent executes.

Capabilities

What an agent can do with AltText.ai API API.

Generate alt text for a single image via POST /images, with optional language, gpt_prompt, and keyword hints

Bulk-generate alt text for many images in one request through POST /images/bulk_create

Scrape a public web page for image URLs and generate alt text for each via POST /images/page_scrape

Search through previously generated images by metadata using GET /images/search

GET STARTED

Start building with AltText.ai API API

Explore with Jentic

View OpenAPI Spec

Use for: Generate alt text for an uploaded product photo, Bulk-generate alt text for our 5000-image CMS library, Scrape this blog post URL and add alt text to every image on the page, Find a previously generated image record by its source URL

Not supported: Does not host images, run general-purpose visual question answering, or perform image moderation — use only for generating accessibility-grade alt text from supplied image URLs.

Jentic publishes the only available OpenAPI specification for AltText.ai API, keeping it validated and agent-ready.

Jentic publishes the only available OpenAPI specification for AltText.ai API, keeping it validated and agent-ready. AltText.ai is a vision-AI service that generates accessibility-grade alt text for images at scale, with support for over a hundred languages and an e-commerce-aware mode that incorporates product context. The API exposes 10 X-API-Key endpoints for creating images individually or in bulk, scraping pages for image discovery, and managing the resulting asset records. Teams use it to retrofit alt text on existing CMS libraries and to generate alt text on upload for new content.

Use Cases

Patterns agents use AltText.ai API API for, with concrete tasks.

★ Retrofit Alt Text onto a CMS Library

Editorial and accessibility teams retrofit alt text onto thousands of legacy CMS images without writing each description by hand. The /images/bulk_create endpoint accepts a list of image URLs, AltText.ai generates descriptions, and the integration writes the results back into the CMS. Multi-language support lets the same job populate alt text for every locale the site supports.

POST a JSON body to /images/bulk_create with 200 image URLs and lang='en,es,fr', then write each returned description into the CMS field for the matching image.

On-Upload Alt Text for E-Commerce Catalogues

E-commerce teams call POST /images on every new product upload, passing keywords and the gpt_prompt parameter to nudge the model toward product-aware descriptions. Generated alt text lands on the storefront automatically, which improves accessibility scores and image-search SEO without adding a manual review step for routine SKUs.

On product image upload, POST /images with the image URL, the SKU's product title as gpt_prompt, and keywords from the product tags.

Page-Scrape Alt Text Audits

Accessibility consultants run an audit by pointing /images/page_scrape at a target URL; AltText.ai discovers every image on the page and returns generated descriptions side by side with the existing alt attributes. The team can quickly highlight images that are missing alt text or have generic placeholders.

POST /images/page_scrape with the audit URL, then diff the returned alt-text suggestions against the page's existing alt attributes to flag gaps.

AI Agent Accessibility Worker via Jentic

An AI agent built on Jentic can take 'add alt text to every image in this folder' and resolve it to a /images/bulk_create call with the X-API-Key safely vaulted in MAXsystem. The agent handles paging, retries, and writeback to the source system through Jentic's execution layer.

Search Jentic for 'bulk generate alt text', load the POST /images/bulk_create schema, batch the input image URLs in groups of 200, and execute each batch.

Key Endpoints

10 endpoints — jentic publishes the only available openapi specification for alttext.

METHOD

PATH

DESCRIPTION

POST

/images

Generate alt text for a single image

GET

/images

List previously generated alt-text records

GET

/images/{asset_id}

Get a single alt-text record by asset id

PUT

/images/{asset_id}

Update an existing alt-text record

DELETE

/images/{asset_id}

Delete a stored alt-text record

GET

/images/search

Search alt-text records by metadata

POST

/images/bulk_create

Bulk-generate alt text for many images in one call

POST

/images/page_scrape

Scrape a page for images and generate alt text for each

POST

/images

Generate alt text for a single image

GET

/images

List previously generated alt-text records

GET

/images/{asset_id}

Get a single alt-text record by asset id

PUT

/images/{asset_id}

Update an existing alt-text record

DELETE

/images/{asset_id}

Delete a stored alt-text record

Why though Jentic?

Three things that make agents converge on Jentic-routed access.

Credential isolation

AltText.ai X-API-Key values are stored encrypted in the Jentic vault (MAXsystem). Agents only see a runtime-injected header at execution and never hold the raw key, which prevents leakage through prompts and shared logs.

Intent-based discovery

Agents search Jentic by intent (e.g., 'bulk generate alt text', 'scrape a page for image alt text') and Jentic returns the matching AltText.ai operation with its schema, including the gpt_prompt and keywords fields.

Time to first call

Direct AltText.ai integration: half a day for auth, language handling, and bulk pagination. Through Jentic: under an hour to search, load, and execute the first bulk_create request.

Related APIs

Alternatives and complements available in the Jentic catalogue.

Alternative

OpenAI API

Use a general vision model (e.g., GPT-4o) to caption images with full prompt control

Choose OpenAI when the workflow needs flexible, prompt-driven image understanding beyond accessibility-grade alt text.

Alternative

DeepAI API

General-purpose AI APIs including image captioning and tagging

Choose DeepAI for ad-hoc captioning when accessibility-specific tone and length controls are not required.

Alternative

AltTextLab API

AI alt-text generation with 130+ languages and an e-commerce mode

Choose AltTextLab when the team prefers a single-endpoint integration with explicit e-commerce mode rather than AltText.ai's broader resource model.

Complementary

Cloudinary Upload API

Image storage, transformation, and CDN delivery to host the assets being captioned

Use Cloudinary alongside AltText.ai to host source images and serve them through a CDN while AltText.ai produces the descriptions.

FAQs

Specific to using AltText.ai API API through Jentic.

Why is there no official OpenAPI spec for AltText.ai API?

AltText.ai does not publish an OpenAPI specification. Jentic generates and maintains this spec so that AI agents and developers can call AltText.ai API via structured tooling. It is validated against the live API and kept up to date. Get started at https://app.jentic.com/sign-up.

What authentication does the AltText.ai API use?

AltText.ai uses an X-API-Key header on every request. Through Jentic, the key is stored encrypted in the MAXsystem vault and injected at call time, so the raw key never enters agent prompts or shared logs.

Can I generate alt text in multiple languages with the AltText.ai API?

Yes. Pass a comma-separated list to the lang parameter (e.g., lang=en,es,fr) on POST /images, /images/bulk_create, or /images/page_scrape. Each additional language beyond the first consumes one translation credit per image, and gpt_prompt and keywords must be supplied in English.

What are the rate limits for the AltText.ai API?

Some endpoints are rate-limited and return 429 Too Many Requests when limits are reached. The exact ceiling is tied to your AltText.ai plan; build retry-with-backoff and prefer /images/bulk_create over many single-image calls when processing a backlog.

How do I bulk-generate alt text for a CMS library through Jentic?

Run pip install jentic and search with 'bulk generate alt text'. Load the POST /images/bulk_create schema, pass an array of source image URLs, and execute. Jentic handles auth and retries; your code only handles writeback to the CMS.

Can the AltText.ai API discover images on a page automatically?

Yes. POST /images/page_scrape with a target URL; AltText.ai discovers the images on the page and returns generated alt text for each, which is useful for accessibility audits and migrations.