Getting Started

🚧 Portal docs are evolving — more APIs and guides coming soon.

Welcome to LDX hub

LDX hub is a document AI gateway — built on 5 years of production infrastructure and 100+ integrated AI vendors. Originally developed at Kawamura International, a Tokyo-based language services company with 40 years of enterprise expertise.

The APIs in this portal are ready-to-use endpoints that wrap the core LDX hub engine. No infrastructure setup required — bring your API key and start processing.

Try it in 60 seconds

Get a free API key, then run two curl commands — the second pipes the first's job_id and waits for the result.

1. Get your API key — Sign up free and grab your API key from the dashboard. No credit card required, 25,000 credits included.

2. Submit and fetch — extract name, email, and intent from a message:

Requires jq for parsing JSON in the shell. Install via your package manager (brew, winget, apt, etc.) — or just copy the job_id manually from the response.

Code
# Submit the job and capture the job_id
JOB_ID=$(curl -s -X POST https://gw.ldxhub.io/structflow/jobs \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "google/gemini-3.5-flash",
    "system_prompt": "Extract the customer name, email, and intent from the message.",
    "example_output": {"name": "John Doe", "email": "[email protected]", "intent": "quote_request"},
    "inputs": [
      {"id": "1", "data": {"message": "Hi, I am Sarah Chen ([email protected]). We need a quote for 50 seats."}}
    ]
  }' | jq -r .job_id)

# Fetch the result — the server holds the connection until the job completes (up to 10s)
curl "https://gw.ldxhub.io/structflow/jobs/$JOB_ID?wait=10" \
  -H "Authorization: Bearer YOUR_API_KEY"

Returns clean, structured JSON:


Code
{
  "status": "completed",
  "results": [
    {
      "id": "1",
      "status": "succeeded",
      "output": {
        "name": "Sarah Chen",
        "email": "[email protected]",
        "intent": "Request a quote for 50 seats"
      }
    }
  ]
}

That's it. Two calls, piped — submit, then wait. The wait=10 parameter holds the connection open for up to 10 seconds, so the result returns as soon as the job is done. For longer-running jobs, just call the same GET again — each call holds for another 10 seconds. Now try it with your own data, your own schema, your own scale.

Built for scale, by design

That same endpoint accepts thousands of inputs in a single call. Drop in 10,000 records — StructFlow runs them in parallel server-side and returns results when the job completes.

Code
curl -X POST https://gw.ldxhub.io/structflow/jobs \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "google/gemini-3.5-flash",
    "system_prompt": "Extract the customer name, email, and intent from the message.",
    "example_output": {"name": "John Doe", "email": "[email protected]", "intent": "quote_request"},
    "inputs": [
      {"id": "1", "data": {"message": "Hi, I am Sarah Chen ([email protected]). We need a quote for 50 seats."}},
      {"id": "2", "data": {"message": "Hey — Mike from BetaCorp here, [email protected]. Can you send pricing?"}},
      {"id": "3", "data": {"message": "Need to renew our contract. — Lisa Park, [email protected]"}}
    ]
  }'

For larger workloads, upload a JSONL file and pass file_id instead of inputs. No rate limit juggling, no client-side concurrency, no retries to write yourself. The async-first design is what makes this scale possible — every endpoint in LDX hub works the same way.

What You Can Do Here

Service	What it does
StructFlow	Unstructured text → structured JSON
RefineLoop	Machine translation → refined translation (XLIFF)
RenderOCR	PDF / images → editable Office files (with OCR)
CastDoc	Text-based PDF → editable Office files (no OCR)
ExtractDoc	Documents → plain text (preprocessing for AI pipelines)

StructFlow

Turn unstructured text into structured data. At scale.

Free-form text — medical records, contracts, reviews, HR notes — is everywhere. StructFlow takes that text, applies your schema and instructions, and returns clean, validated JSON. Fast. In parallel. With output structure guaranteed by Structured Outputs technology.

Works with any major AI engine (Claude, Gemini, GPT, Amazon Nova, Grok, and more)
Define your output schema from a single sample JSON line
Built for batch: drop a JSONL file, get a JSONL file back
5 years of production-hardened parallel processing under the hood

→ Learn more about StructFlow

RefineLoop

Machine translation quality, refined until it converges.

RefineLoop takes MT output in XLIFF format and runs it through an AI review loop — checking for mistranslations, omissions, and additions across three axes. It keeps revising until the AI agrees with itself. That's the convergence.

Drops into any existing translation pipeline as a single XLIFF step
Compatible with XTM, memoQ, Trados, and other CAT tools
Revision history recorded in alt-trans tags — fully auditable
Powered by the same parallel processing engine as StructFlow

→ Learn more about RefineLoop

RenderOCR

Scanned documents, converted to editable Office files — with layout intact.

PDFs and images sitting in your archive aren't searchable, editable, or pipeline-ready. RenderOCR runs high-fidelity OCR across your documents and returns Word, Excel, or PowerPoint files that preserve the original layout and formatting — not just raw text dumps.

Supports PDF, TIFF, JPEG, PNG, and BMP as input
Output to DOCX, XLSX, or PPTX — your choice
120+ languages supported, including Japanese, Chinese, Korean, Arabic, and more
Powered by KI OCR, a battle-tested enterprise OCR engine

CastDoc

PDF files, converted to editable Office formats — without OCR.

Already have a text-based PDF? CastDoc converts it directly to Word, Excel, or PowerPoint while preserving the original layout and formatting — no optical recognition required. Faster and more accurate than OCR for born-digital documents.

Input: text-based PDF (not scanned)
Output to DOCX, XLSX, or PPTX — your choice
Powered by KI Cast
Ideal for contracts, reports, and any PDF created from digital sources

ExtractDoc

Documents to plain text — fast, deterministic, and pipeline-ready.

Need just the text from a document? ExtractDoc pulls plain text from PDFs and Office files in reading order, with no AI overhead and no layout assumptions. Designed as the entry point for StructFlow and other downstream AI pipelines.

Supports PDF, DOCX, XLSX, and PPTX as input
Output as plain text or as JSONL — directly compatible with StructFlow's file_id input
No AI billing, no language settings, no parameters to tune
Built to chain: pair with StructFlow for extraction, RefineLoop for translation review

Getting Started

Sign up free to get your API key instantly — no credit card required, 25,000 credits included. Then head to the API Reference to explore all available endpoints, request/response formats, and authentication details.

Credits & Pricing

LDX hub uses a credit-based billing system. Credits are consumed based on the engine you choose and the volume of data processed.

→ Credits & Pricing

Use Anywhere

LDX hub works as a backend for your existing tools:

Dify — LDX hub plugin brings StructFlow and RefineLoop into your Dify workflows
n8n — n8n-nodes-ldxhub exposes all 5 services in n8n automations
Claude Desktop / MCP-compatible AI — see MCP Setup below
Direct API — start with the curl examples above

Use with AI Assistants (MCP)

LDX hub supports the Model Context Protocol (MCP), allowing you to use StructFlow, RefineLoop, RenderOCR, CastDoc, and ExtractDoc directly from AI assistants like Claude Desktop.

→ MCP Setup Guide

Last modified on May 28, 2026

Credits & Pricing

Getting Started

🚧 Portal docs are evolving — more APIs and guides coming soon.

Welcome to LDX hub

The APIs in this portal are ready-to-use endpoints that wrap the core LDX hub engine. No infrastructure setup required — bring your API key and start processing.

Try it in 60 seconds

Get a free API key, then run two curl commands — the second pipes the first's job_id and waits for the result.

1. Get your API key — Sign up free and grab your API key from the dashboard. No credit card required, 25,000 credits included.

2. Submit and fetch — extract name, email, and intent from a message:

Requires jq for parsing JSON in the shell. Install via your package manager (brew, winget, apt, etc.) — or just copy the job_id manually from the response.

Code
# Submit the job and capture the job_id
JOB_ID=$(curl -s -X POST https://gw.ldxhub.io/structflow/jobs \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "google/gemini-3.5-flash",
    "system_prompt": "Extract the customer name, email, and intent from the message.",
    "example_output": {"name": "John Doe", "email": "[email protected]", "intent": "quote_request"},
    "inputs": [
      {"id": "1", "data": {"message": "Hi, I am Sarah Chen ([email protected]). We need a quote for 50 seats."}}
    ]
  }' | jq -r .job_id)

# Fetch the result — the server holds the connection until the job completes (up to 10s)
curl "https://gw.ldxhub.io/structflow/jobs/$JOB_ID?wait=10" \
  -H "Authorization: Bearer YOUR_API_KEY"

Returns clean, structured JSON:


Code
{
  "status": "completed",
  "results": [
    {
      "id": "1",
      "status": "succeeded",
      "output": {
        "name": "Sarah Chen",
        "email": "[email protected]",
        "intent": "Request a quote for 50 seats"
      }
    }
  ]
}

Built for scale, by design

That same endpoint accepts thousands of inputs in a single call. Drop in 10,000 records — StructFlow runs them in parallel server-side and returns results when the job completes.

Code
curl -X POST https://gw.ldxhub.io/structflow/jobs \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "google/gemini-3.5-flash",
    "system_prompt": "Extract the customer name, email, and intent from the message.",
    "example_output": {"name": "John Doe", "email": "[email protected]", "intent": "quote_request"},
    "inputs": [
      {"id": "1", "data": {"message": "Hi, I am Sarah Chen ([email protected]). We need a quote for 50 seats."}},
      {"id": "2", "data": {"message": "Hey — Mike from BetaCorp here, [email protected]. Can you send pricing?"}},
      {"id": "3", "data": {"message": "Need to renew our contract. — Lisa Park, [email protected]"}}
    ]
  }'

What You Can Do Here

Service	What it does
StructFlow	Unstructured text → structured JSON
RefineLoop	Machine translation → refined translation (XLIFF)
RenderOCR	PDF / images → editable Office files (with OCR)
CastDoc	Text-based PDF → editable Office files (no OCR)
ExtractDoc	Documents → plain text (preprocessing for AI pipelines)

StructFlow

Turn unstructured text into structured data. At scale.

Works with any major AI engine (Claude, Gemini, GPT, Amazon Nova, Grok, and more)
Define your output schema from a single sample JSON line
Built for batch: drop a JSONL file, get a JSONL file back
5 years of production-hardened parallel processing under the hood

→ Learn more about StructFlow

RefineLoop

Machine translation quality, refined until it converges.

Drops into any existing translation pipeline as a single XLIFF step
Compatible with XTM, memoQ, Trados, and other CAT tools
Revision history recorded in alt-trans tags — fully auditable
Powered by the same parallel processing engine as StructFlow

→ Learn more about RefineLoop

RenderOCR

Scanned documents, converted to editable Office files — with layout intact.

Supports PDF, TIFF, JPEG, PNG, and BMP as input
Output to DOCX, XLSX, or PPTX — your choice
120+ languages supported, including Japanese, Chinese, Korean, Arabic, and more
Powered by KI OCR, a battle-tested enterprise OCR engine

CastDoc

PDF files, converted to editable Office formats — without OCR.

Input: text-based PDF (not scanned)
Output to DOCX, XLSX, or PPTX — your choice
Powered by KI Cast
Ideal for contracts, reports, and any PDF created from digital sources

ExtractDoc

Documents to plain text — fast, deterministic, and pipeline-ready.

Supports PDF, DOCX, XLSX, and PPTX as input
Output as plain text or as JSONL — directly compatible with StructFlow's file_id input
No AI billing, no language settings, no parameters to tune
Built to chain: pair with StructFlow for extraction, RefineLoop for translation review

Getting Started

Credits & Pricing

LDX hub uses a credit-based billing system. Credits are consumed based on the engine you choose and the volume of data processed.

→ Credits & Pricing

Use Anywhere

LDX hub works as a backend for your existing tools:

Dify — LDX hub plugin brings StructFlow and RefineLoop into your Dify workflows
n8n — n8n-nodes-ldxhub exposes all 5 services in n8n automations
Claude Desktop / MCP-compatible AI — see MCP Setup below
Direct API — start with the curl examples above

Use with AI Assistants (MCP)

LDX hub supports the Model Context Protocol (MCP), allowing you to use StructFlow, RefineLoop, RenderOCR, CastDoc, and ExtractDoc directly from AI assistants like Claude Desktop.

→ MCP Setup Guide

Last modified on May 28, 2026

Credits & Pricing