# Fileverity API docs > Developer documentation for the Fileverity API: check images, documents and plain text for AI generation, tampering and AI-written passages. Every page is also available as Markdown at the same path plus .md. ## At a glance - Base URL: `https://api.fileverity.com/v1` (HTTPS only, JSON). - Authentication: a bearer API key in the `Authorization` header. Live keys start with `fv_live_`; test keys start with `fv_test_`, return fixed sample results and are never charged. - Image check: model `fvimg-2` (FVIMG V2), US$1.99 per image. Upload with `POST /files`, then `POST /analyses`. - Document check: model `fvdoc-3` (FVDOC V3), US$5.99 per document. Upload with `POST /files`, then `POST /analyses`. - Text check: model `fvdoc-3-text` (FVDOC V3 Text), US$0.14 per 1,000 characters, at least 100 words. One synchronous call to `POST /text/detections`. The API is prepaid, with no subscription: add funds to your workspace balance from US$19. Your first workspace starts with 5 free image or document checks and 5,000 free text characters. Failed checks are not charged. The balance stays valid for 12 months after your latest top-up, and top-ups are non-refundable except where required by law or stated in your agreement. Uploaded files are deleted when the analysis starts, and at the latest after 24 hours. Text you send is not stored. Results are kept for 7 days. ## Start - [Overview](https://fileverity.com/en/docs.md): The Fileverity API checks images, documents and plain text for AI generation, tampering and AI-written passages. Base URL, models, conventions and where to start. - [Quickstart](https://fileverity.com/en/docs/quickstart.md): Create a workspace, make an API key and run your first text and image checks with cURL, JavaScript fetch or Python requests. - [Authentication and keys](https://fileverity.com/en/docs/authentication.md): Authenticate with bearer API keys. Live and test keys, what test mode returns, revoking a key and setting a monthly spend limit per key. ## Guides - [Text detections](https://fileverity.com/en/docs/text-detections.md): Classify plain text as AI-written, mixed or human-written with POST /text/detections. Request and response fields, segment offsets, limits and billing. - [Files](https://fileverity.com/en/docs/files.md): Upload images and documents to Fileverity: multipart for files up to 4 MB, pre-signed upload for files up to 50 MB. File object, limits and retention. - [Analyses](https://fileverity.com/en/docs/analyses.md): Create image and document analyses, wait for the result with Prefer: wait or poll, cancel, download the PDF report and read the report object and verification page. - [Webhooks](https://fileverity.com/en/docs/webhooks.md): Receive analysis.completed, analysis.failed and balance.low events. Standard Webhooks signature verification in JavaScript and Python, retries, auto-disable and the test event. - [Idempotency](https://fileverity.com/en/docs/idempotency.md): Send an Idempotency-Key on POST requests so a retried request never runs, or bills, a check twice. Behavior, replays and conflicts. - [Sample code](https://fileverity.com/en/docs/sample-code.md): Complete Node.js and Python programs for the Fileverity API: check an image, check a large PDF, detect AI-written text and verify webhook signatures. - [Document checks in an intake workflow](https://fileverity.com/en/docs/intake-workflow.md): Add document checks to an intake flow: upload, receive the webhook, route by risk level, queue human review, store the report ID and verify it later. - [Errors](https://fileverity.com/en/docs/errors.md): The Fileverity API error format, HTTP statuses and the complete table of error codes, with guidance on which errors to retry. - [Rate limits and headers](https://fileverity.com/en/docs/rate-limits.md): Request rate limits per API key, the rate-limit response headers, retry-after on 429 and 503 and the other headers the Fileverity API sets. - [Pricing and billing](https://fileverity.com/en/docs/pricing.md): Fileverity API models, prices and limits, the prepaid balance, its validity and refunds, the free start, spend limits, auto-recharge and low-balance alerts. - [Data retention and security](https://fileverity.com/en/docs/security.md): What the Fileverity API stores and for how long: uploaded files, results, text, request logs and webhook deliveries, and how keys and endpoints are protected. ## Reference - [API reference](https://fileverity.com/en/docs/api-reference.md): Every Fileverity API endpoint with parameters, request and response schemas, error codes and examples, generated from the OpenAPI 3.1 specification. - [Changelog](https://fileverity.com/en/docs/changelog.md): Changes to the Fileverity API. Version 1 launched in November 2026. ## Machine-readable - [OpenAPI 3.1 specification](https://api.fileverity.com/v1/openapi.json): the source of the API reference. - [All docs pages in one file](https://fileverity.com/en/docs/llms-full.txt): every page above, concatenated as Markdown.