AltTextLab API

Name: AltTextLab API
Brand: AltTextLab API
Availability: InStock

★ Only Publicly Available OpenAPI DocumentAI/MLVisionapiKey1 EndpointsREST

For Agents

Generate AI alt text for an image through a single x-api-key endpoint with 130+ language support and e-commerce mode. Useful for agents adding accessibility-grade descriptions to web, e-commerce, and email images.

Install Jentic One Beta

Connect the AltTextLab API to your agent

Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the AltTextLab API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.

Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.

Step 1: Jentic One Host machine

# On the machine that will host your Jentic One instance:
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh

Step 2: Agent machine

# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh
jentic register       # connects your agent to your Jentic One instance

Jentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.

Capabilities

What an agent can do with AltTextLab API.

Generate alt text for an image by URL via POST /alt-text/generate

Request alt text in any of 130+ supported languages on a per-call basis

Use e-commerce mode to generate product-aware descriptions for storefront imagery

GET STARTED

Start building with AltTextLab API

Explore with Jentic

View OpenAPI Document

Use Cases

Patterns agents use AltTextLab API for, with concrete tasks.

★ On-Upload Alt Text for E-Commerce Catalogues

E-commerce teams call POST /alt-text/generate on every product image upload, optionally enabling e-commerce mode so the description leans into product attributes rather than generic visual cues. The single-endpoint design makes the integration trivial: one HTTP client and one header.

POST /alt-text/generate with the product image URL, lang='en', and e-commerce mode enabled, then write the returned alt text into the storefront's image record.

Multi-Language Localisation

Multinational sites get alt text per locale by calling the endpoint once per language. AltTextLab supports more than 130 languages, so the same workflow that populates English alt text can produce localised descriptions for the same image without a separate translation tool.

Loop over the site's locale list and call POST /alt-text/generate for each language, storing each result on the image record under that locale's column.

Accessibility Backfill Project

Accessibility teams running a backfill on an existing image library iterate through the asset list and call /alt-text/generate per image. Because every call is independent, the workflow parallelises easily and resumes cleanly after interruptions; the single-endpoint surface keeps the worker code small.

Iterate over the image inventory and call POST /alt-text/generate for any image that has no alt attribute, writing the response back to the asset record.

AI Agent Image Captioner via Jentic

An AI agent built on Jentic can take 'caption this image for our blog post in English and Spanish' and resolve it to two POST /alt-text/generate calls with the x-api-key safely vaulted in your Jentic One instance. Jentic returns the schema directly so the agent doesn't need to know the request body shape in advance.

Search Jentic for 'generate alt text for an image', load the POST /alt-text/generate schema, and execute it twice with lang='en' and lang='es' for the same image URL.

Key Endpoints

1 endpoints — jentic publishes the only available openapi specification for alttextlab api, keeping it validated and agent-ready.

METHOD

PATH

DESCRIPTION

POST

/alt-text/generate

Generate alt text for an image, with optional language and e-commerce mode

POST

/alt-text/generate

Generate alt text for an image, with optional language and e-commerce mode

Why Jentic?

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

Credential isolation

Your AltTextLab API key is stored once, encrypted, by your own Jentic One instance and injected at execution time. It never enters the agent's prompt, logs, or context.

Intent-based discovery

Agents search Jentic by intent such as 'generate alt text from an image URL', and Jentic returns the matching AltTextLab operation with its input schema so the agent calls the right endpoint without browsing the reference docs.

Time to first call

FAQs

Specific to using AltTextLab API through Jentic.

Why is there no official OpenAPI spec for AltTextLab API?

AltTextLab does not publish an OpenAPI specification. Jentic generates and maintains this spec so that AI agents and developers can call AltTextLab API via structured tooling. It is validated against the live API and kept up to date. Get started with Jentic One, the self-hosted execution layer.

What authentication does the AltTextLab API use?

AltTextLab uses an x-api-key header on every request. Through Jentic, the key stays encrypted in your Jentic One instance and the header is injected at call time, so the raw key never enters agent prompts.

Can I generate alt text in multiple languages with the AltTextLab API?

Yes. AltTextLab supports more than 130 languages. Pass the desired language code on POST /alt-text/generate to get the description in that locale, and call the endpoint again for each additional language you need.

What are the rate limits for the AltTextLab API?

Specific limits are not documented in the spec. Treat the endpoint as account-throttled and add retry-with-backoff for 429 responses; for backfill jobs of more than a few thousand images, contact AltTextLab to size the workload against your plan.

How do I generate alt text for a product image through Jentic?

Run pip install jentic and search with 'generate alt text for an image'. Load the POST /alt-text/generate schema, pass the image URL with e-commerce mode enabled, and execute. Jentic injects the x-api-key header from the vault.

Does the AltTextLab API have an e-commerce mode?

Yes. AltTextLab exposes an e-commerce mode that biases the description toward product attributes - colour, shape, fit, and visible branding - which is useful for storefront imagery where generic 'a man stands in a room' style alt text is unhelpful.

Can I limit what my agent is allowed to do with the AltTextLab API?

Yes. Because you run Jentic One yourself, your own rules decide which operations and credentials the agent may use. The AltTextLab API exposes a single POST /alt-text/generate operation, with the image target passed in the request body rather than a path resource, so you can restrict the agent to that one operation and no other. You decide whether the agent may call it at all, and there are no additional operations to grant.