WebCite API

API documentation for WebCite public API endpoints. Use these endpoints to verify claims, search for sources, and manage citations.

Overview

Base URL

text

https://devapi.webcite.co/api

Authentication

All endpoints require authentication using an API key. Include your API key in the request headers.

bash

x-api-key: your-api-key-here

You can create and manage API keys from the API Keys page.

Credit System

WebCite uses a credit-based billing system. Each API operation consumes credits from your monthly allocation. Credits are charged per claim, not per citation - each API call verifies 1 claim and returns multiple citations.

Credit Costs

Citation search costs 2 credits. Full verification (default) costs 4 credits total.

Operation	Credits	Description
`Citation/Search`	2	Search web sources for a claim. Returns multiple citations.
`Stance Analysis`	1	Analyze if citations support or contradict the claim. Optional
`Verdict`	1	Generate overall verification verdict. Optional
Full Verification	4	Citation + Stance + Verdict (default)

Saving Credits

Control which operations run to reduce credit usage.

json

// Citation only (2 credits){  "prompt": "Your claim here",  "include_stance": false,  "include_verdict": false} // Citation + Stance (3 credits){  "prompt": "Your claim here",  "include_verdict": false} // Full verification (3 credits) - default{  "prompt": "Your claim here"}

Plans

Plan	Credits/Month	Price
Free	100	$0
Builder	500	$20
Enterprise	Custom	Custom

Checking Your Credits

GET/v1/payment/subscription/credits

json

{  "credits": {    "used": 12,    "remaining": 88,    "total": 100  },  "usage_breakdown": {    "citations": 8,    "stances": 3,    "verdicts": 1  },  "allow_overage": true,  "billing_period_start": "2026-01-01T00:00:00.000Z",  "billing_period_end": "2026-01-31T23:59:59.000Z"}

Overage Billing Settings

Paid plans (Builder/Enterprise) can toggle overage billing on or off.

Get Current Setting

GET/v1/payment/subscription/overage-setting

json

{  "allow_overage": true,  "plan_type": "builder",  "can_toggle": true}

Toggle Overage Billing

PUT/v1/payment/subscription/overage-setting

json

// Request{ "allow_overage": false } // Response{  "allow_overage": false,  "message": "Overage billing disabled. Requests will be blocked when credits are exhausted."}

When overage is disabled, API requests return 400 error when credits are exhausted. When enabled, overages are billed at $0.03/credit.

Credit Usage in Responses

Credit usage is included in stream metadata events.

json

// Metadata event in stream response{  "type": "metadata",  "data": {    "thread_id": "...",    "citation_id": "...",    "creditUsage": {      "credits_used": 3,      "credits_remaining": 47    }  }}

Important Notes

Credits are charged per claim, not per citation
Each API call verifies 1 claim and returns multiple citations
All citations for a claim are covered by the credit cost
Credits reset at the start of each billing period

Verify Claim

Verify a factual claim against authoritative sources. Returns sources with stance analysis and an overall verdict.

POST/api/v1/verify

Request

curl

curl -X POST 'https://devapi.webcite.co/api/api/v1/verify' \  -H 'Content-Type: application/json' \  -H 'x-api-key: YOUR_API_KEY' \  -d '{    "claim": "The Eiffel Tower is 330 meters tall",    "include_stance": true,    "include_verdict": true  }'

Parameters

Parameter	Type	Description
`claim`required	string	The factual claim to verify
`thread_id`optional	string	Thread ID to continue a conversation
`include_stance`optional	boolean	Include stance analysis for each source (supports/contradicts/neutral). Adds 1 credit. Default: `true`
`include_verdict`optional	boolean	Generate an overall verdict with confidence score. Adds 1 credit. Default: `true`
`decompose_claim`optional	boolean	Break complex claims into atomic sub-claims and verify each independently. Default: `false`

Response

json

{  "citations": [    {      "title": "TypeScript Official Documentation",      "url": "https://www.typescriptlang.org/docs/",      "snippet": "TypeScript is a strongly typed programming language...",      "id": "1",      "author": "typescriptlang",      "status": "verified",      "source_type": "Article"    }  ],  "totalResults": 5,  "thread_id": "123e4567-e89b-12d3-a456-426614174000"}

Streaming Verification (SSE)

Stream verification results in real-time using Server-Sent Events. Citations are streamed as they are processed, followed by groups, verdict, and metadata.

POST/api/v1/verify/stream

Event Types

citationIndividual citations as they are processed

groupsCitation groups by domain (if useEnhancedAnalysis)

verdictOverall verdict result (if useEnhancedAnalysis)

decompositionClaim broken into sub-claims (if useClaimDecomposition)

sub-claim-startStarting verification of a sub-claim

sub-claim-resultResult for a sub-claim verification

metadataThread ID, citation ID, totals, processing time

doneStream complete

errorError occurred (if applicable)

JavaScript Example

javascript

const response = await fetch('https://devapi.webcite.co/api/api/v1/verify/stream', {  method: 'POST',  headers: {    'Content-Type': 'application/json',    'x-api-key': 'YOUR_API_KEY'  },  body: JSON.stringify({ claim: 'The Eiffel Tower is 330 meters tall' })}); const reader = response.body.getReader();const decoder = new TextDecoder(); while (true) {  const { done, value } = await reader.read();  if (done) break;   const chunk = decoder.decode(value);  const lines = chunk.split('\n').filter(line => line.startsWith('data: '));   for (const line of lines) {    const event = JSON.parse(line.slice(6));     switch (event.type) {      case 'citation':        console.log('New citation:', event.data);

Search Sources

Search for authoritative sources related to a query. Returns raw citations without stance analysis or verdict. Use this for cheaper, faster searches when you don't need verification.

POST/api/v1/sources/search

Credits: 2 (search only, no analysis)

Request

curl

curl -X POST 'https://devapi.webcite.co/api/api/v1/sources/search' \  -H 'Content-Type: application/json' \  -H 'x-api-key: YOUR_API_KEY' \  -d '{    "query": "climate change effects on coral reefs",    "limit": 10  }'

Parameters

Parameter Type Description

Parameter	Type	Description
`query`required	string	Search query to find sources for
`limit`optional	number	Maximum number of sources to return (1-20) Default: `10`

queryrequired

string

Search query to find sources for

limitoptional

number

Maximum number of sources to return (1-20)

Default: 10

Enhanced Analysis

When useEnhancedAnalysis: true is set, the API returns additional fields that help you understand whether sources support or contradict the claim, and an overall verdict.

Enhanced Citation Fields

Each citation object includes these additional optional fields when enhanced analysis is enabled.

json

{  "title": "Example Source",  "url": "https://example.com/article",  "snippet": "The research confirms that...",  "credibility_score": 92,   // Enhanced Analysis Fields  "stance": "supports",  "stance_confidence": 88,  "stance_explanation": "Source directly confirms the claim with data.",  "highlight_terms": ["research confirms", "data shows"],  "source_metadata": {    "domain": "example.gov",    "domain_category": "government",    "is_primary_source": true,    "is_fact_check_site": false  }}

Verdict Object

The response includes an overall verdict summarizing how all citations relate to the claim.

json

{  "verdict": {    "claim": "AI is transforming healthcare",    "result": "supported",    "confidence": 85,    "summary": "Based on 4 authoritative sources, the claim is well-supported.",    "stance_breakdown": {      "supports": 3,      "partially_supports": 1,      "contradicts": 0,      "neutral": 1    },    "key_findings": [      {        "finding": "AI diagnostic tools show 95% accuracy",        "citation_ids": ["1", "3"],        "confidence": 92      }    ],    "corrections": [],

Usage Notes

Enhanced analysis adds processing time and token usage
All enhanced fields are optional and only present when useEnhancedAnalysis: true
If enhanced analysis fails, the API returns basic response

Claim Decomposition

Optional feature. When verifying complex claims containing multiple facts, set useClaimDecomposition: true to automatically break the claim into atomic sub-claims and verify each independently. This provides more accurate verification and identifies exactly which parts of a claim are true or false. Default is false (standard single-claim verification).

Example Request

Complex claim with multiple verifiable facts

json

{  "prompt": "Tesla is the best-selling EV company founded by Elon Musk",  "useEnhancedAnalysis": true,  "useClaimDecomposition": true}

Decomposition Event

First event showing how the claim was broken down

json

{  "type": "decomposition",  "data": {    "original_claim": "Tesla is the best-selling EV company founded by Elon Musk",    "sub_claims": [      {        "id": "sub-1",        "claim": "Tesla is the best-selling EV company",        "status": "pending"      },      {        "id": "sub-2",        "claim": "Elon Musk founded Tesla",        "status": "pending"      }    ],    "decomposition_reasoning": "The claim contains two distinct verifiable facts..."  }}

Sub-Claim Result Event

Result for each verified sub-claim

json

{  "type": "sub-claim-result",  "data": {    "sub_claim_id": "sub-2",    "claim": "Elon Musk founded Tesla",    "result": "contradicted",    "confidence": 68,    "summary": "5 of 8 sources contradict this claim.",    "citation_count": 8,    "supporting_count": 0,    "contradicting_count": 5,    "top_citations": [      {        "id": "1",        "title": "wikipedia.org",        "url": "https://en.wikipedia.org/wiki/Tesla,_Inc.",        "stance": "contradicts",        "credibility_score": 69      }    ]  }}

Overall Verdict with Corrections

Final verdict showing which sub-claims were verified or contradicted

json

{  "type": "verdict",  "data": {    "claim": "Tesla is the best-selling EV company founded by Elon Musk",    "result": "partially_false",    "confidence": 75,    "summary": "Analyzed 2 sub-claims: 1 verified, 1 contradicted.",    "stance_breakdown": {      "supports": 1,      "partially_supports": 0,      "contradicts": 1,      "neutral": 0    },    "corrections": [      {        "claimed": "Elon Musk founded Tesla",        "actual": "Evidence contradicts this claim",        "citation_ids": ["1", "2"]      }    ]  }}

When to Use Claim Decomposition

Claims containing multiple facts (e.g., "X was founded by Y in Z")
Statements with conjunctions (and, but, while, because)
Complex assertions that need granular verification
When you need to know exactly which parts are true vs false

Unified Response Structure

All responses use a unified tree structure with claim_groups as the single source of truth. Each claim contains its citations, domain groups, and verdict - no duplication.

Unified Tree Structure

Both single-claim and multi-claim queries use the same structure. Verdicts stream in parallel as each claim's citations complete.

json

{  "claim_groups": [    {      "claim_id": "claim-1",      "claim_index": 1,      "claim": "Tesla was founded by Elon Musk",      "stance_summary": "contradicted",      "citation_count": 5,      "citations": [        {          "id": "1",          "title": "Wikipedia - Tesla, Inc.",          "url": "https://en.wikipedia.org/wiki/Tesla,_Inc.",          "snippet": "Tesla was founded by Martin Eberhard and Marc Tarpenning...",          "stance": "contradicts",          "credibility_score": 85        }      ],      "domain_groups": [        {          "group_id": "group-wikipedia-org",          "domain": "wikipedia.org",          "domain_category": "encyclopedia",          "group_stance": "contradicts",          "citation_ids": ["1"],          "primary_citation_id": "1"        }      ],      "verdict": {        "claim": "Tesla was founded by Elon Musk",        "result": "contradicted",        "confidence": 85,        "summary": "Tesla was founded by Eberhard and Tarpenning, not Musk.",        "stance_breakdown": {          "supports": 0,          "partially_supports": 1,          "contradicts": 4,          "neutral": 0        }      }    }  ],  "totalResults": 5,  "thread_id": "123e4567-e89b-12d3-a456-426614174000",  "generated_prompts": []

Key Benefits

No duplication: Citations only appear in their claim_group
Parallel verdicts: Each claim's verdict streams as its citations complete
Single tree: claim_groups → citations + domain_groups + verdict
Consistent structure: Same format for single and multi-claim queries

Legacy Fields (Deprecated)

For backward compatibility, top-level fields are still included but deprecated.

citations → Use claim_groups[n].citations

verdict → Use claim_groups[n].verdict

citation_groups → Use claim_groups[n].domain_groups

List Citations

Retrieves a paginated list of citations generated by the authenticated user.

GET/api/v1/citations

Parameters

Parameter	Type	Description
`page`optional	number	Page number (starts from 1) Default: `1`
`limit`optional	number	Number of items per page (max 100) Default: `20`
`thread_id`optional	string	Filter citations by thread ID
`fields`optional	enum	Field set: minimal, basic, detailed, with_relations, all Default: `basic`

Response

json

{  "statusCode": 200,  "message": "Citations fetched successfully",  "data": [    {      "id": "123e4567-e89b-12d3-a456-426614174000",      "thread_id": "thread-123",      "citation": "[{\"title\":\"Example\",\"url\":\"https://example.com\"}]",      "prompt": "Latest trends in AI",      "is_active": true,      "created_at": "2024-01-01T00:00:00.000Z"    }  ],  "pagination": {    "total": 100,    "page": 1,    "limit": 20,    "totalPages": 5,    "hasNextPage": true,    "hasPreviousPage": false

Get Citation by ID

Retrieves a specific citation by its ID for the authenticated user.

GET/api/v1/citations/:id

Path Parameters

Parameter	Type	Description
`id`required	string	The unique identifier of the citation

Response

json

{  "statusCode": 200,  "message": "Citation fetched successfully",  "data": {    "prompt": "Latest trends in AI",    "citation": "[{\"title\":\"Example\",\"url\":\"https://example.com\"}]"  }}

Error Response (404)

json

{  "statusCode": 404,  "message": "Citation not found or does not belong to the user"}

Upload File

Uploads a file to storage and creates an asset record. Files are automatically sanitized and made publicly accessible.

POST/api/v1/upload

Content-Type: multipart/form-data

Request

bash

curl -X POST 'https://devapi.webcite.co/api/api/v1/upload' \  -H 'x-api-key: YOUR_API_KEY' \  -F 'file=@/path/to/your/file.pdf'

Response

json

{  "statusCode": 200,  "message": "File uploaded successfully",  "data": {    "asset_id": "123e4567-e89b-12d3-a456-426614174000",    "asset_url": "https://storage.googleapis.com/bucket-name/path/to/file.pdf"  }}

Data Structures

Citation Object

json

{  // Required fields  "title": "TypeScript Official Documentation",  "url": "https://www.typescriptlang.org/docs/",  "snippet": "TypeScript is a strongly typed programming language...",  "id": "1",  "author": "typescriptlang",  "status": "verified",  "credibility_score": 95,   // Optional fields  "source_type": "Article",  "publication_year": 2024,   // Enhanced Analysis fields (only with useEnhancedAnalysis: true)  "stance": "supports",  "stance_confidence": 90,  "stance_explanation": "Source directly confirms the claim"}

source_type can be: Government Document, Dataset, Journal, Report, Trusted Media, Article, Reddit, Social Media

stance can be: supports, contradicts, partially_supports, neutral, inconclusive

Pagination Object

json

{  "total": 100,  "page": 1,  "limit": 20,  "totalPages": 5,  "hasNextPage": true,  "hasPreviousPage": false}

Integrations

WebCite integrates with popular AI platforms and automation tools. Use these integrations to add fact-verification to your workflows.

ClaudeMCP Server

Connect WebCite to Claude Desktop or Claude Code via Model Context Protocol (MCP).

Install via npm

bash

npm install -g webcite-mcp-server

View on npm: webcite-mcp-server

Claude Desktop Configuration

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

json

{  "mcpServers": {    "webcite": {      "command": "npx",      "args": ["-y", "webcite-mcp-server"],      "env": {        "WEBCITE_API_KEY": "wc_your_api_key_here"      }    }  }}

Claude Code

bash

claude mcp add webcite -- npx -y webcite-mcp-serverexport WEBCITE_API_KEY=wc_your_api_key_here

Available Tools

verify_claimFull verification with stance analysis and verdict

2-4 credits

search_sourcesSearch for authoritative sources (citations only)

2 credits

list_citationsList your past verification results

0 credits

get_citationGet details of a specific verification

0 credits

Example Usage

In Claude, say: "Use WebCite to verify: The Eiffel Tower is 330 meters tall"

ChatGPTGPT Actions

Add WebCite fact-checking to any ChatGPT Plus GPT using OpenAI Actions.

Setup Instructions

Go to ChatGPT → Explore GPTs → Create
In the "Configure" tab, scroll to "Actions"
Click "Create new action"
Import the OpenAPI schema below
Add your WebCite API key as authentication

OpenAPI Schema URL

text

https://api.webcite.co/openapi/gpt-actions.yaml

Authentication

In the Actions configuration, set:

Authentication type: API Key
Auth Type: Custom
Custom Header Name: x-api-key

Example Usage

Ask your GPT: "Fact check this: Electric vehicles produce more CO2 than gas cars"

ZapierZapier Integration

Automate fact-checking in your workflows with 6000+ app integrations.

Available Actions

Verify ClaimWhen triggered

Full verification with sources and verdict

Search SourcesWhen triggered

Find authoritative sources for a topic

Batch VerifyWhen triggered

Verify multiple claims from a spreadsheet row

Example Workflows

Slack channel → WebCite verify → Post result back
Google Sheet row → Batch verify claims → Update sheet
Email received → Extract claims → Verify → Reply

Unlock Full Integration Access

Free plan includes 100 credits/month. Upgrade to Builder for 500 credits and higher rate limits.

Rate Limits

API rate limits vary by plan. Exceeding limits returns a 429 error with retry information.

Rate Limits by Plan

Plan	Requests/Min	Requests/Day	Concurrent
Free	10	100	2
Builder	30	1,000	5
Enterprise	100+	Custom	Custom

Rate Limit Headers

All API responses include rate limit information in headers.

text

X-RateLimit-Limit: 30X-RateLimit-Remaining: 28X-RateLimit-Reset: 1706659200X-Credits-Used: 4X-Credits-Remaining: 496

429 Rate Limit Error

When rate limit is exceeded, the API returns a 429 status with retry information.

json

{  "statusCode": 429,  "message": "Rate limit exceeded. Please wait 45 seconds.",  "error": "Too Many Requests",  "retryAfter": 45}

Best Practices

Implement exponential backoff when receiving 429 errors
Use batch_verify for multiple claims instead of individual calls
Cache verification results to avoid redundant API calls
Monitor X-RateLimit-Remaining to proactively manage usage

Need Higher Limits?

Enterprise plans include custom rate limits, dedicated support, and SLA guarantees.

For more information, visit WebCite