Filestack API
★ Only Publicly Available OpenAPI DocumentMediaImage ProcessingapiKey9 EndpointsREST
For Agents
Upload, transform, and deliver files via Filestack's nine endpoints across upload, processing, and CDN hosts using a query-string API key.
Use for: Upload a file to Filestack from a user-supplied URL, Transform a Filestack image to a 600x400 thumbnail, Retrieve metadata for a Filestack file by handle, Delete a Filestack file by handle
Not supported: Does not handle persistent DAM cataloguing, video conferencing, or e-signature workflows - use for upload, transform, and delivery of files only.
Jentic publishes the only available OpenAPI specification for Filestack API, keeping it validated and agent-ready. The Filestack API is a file-handling platform spanning upload (multipart and URL-based), metadata, transformations, and CDN delivery across five hostnames - the File API, Upload API, CDN, Processing API, and Cloud API. Authentication is by query-string API key, with optional security policy and signature parameters for signed URLs. Filestack is used by product teams that need to embed reliable upload widgets and on-the-fly image processing without operating their own ingestion pipeline.
Install Jentic One Beta
Connect the Filestack API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Filestack 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.
1
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 | sh2
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 instanceJentic 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 Filestack API.
Upload files via single-shot POST /store/{storeLocation} or chunked multipart endpoints
Run on-the-fly image transformations via the processing host with chained transform tokens
Fetch file binaries and metadata by handle for downstream rendering or analysis
Generate signed URLs using Filestack security policies and HMAC-SHA256 signatures
Delete a file by handle when content is retired from a product or campaign
Initiate a multipart upload session for large files and resume on failure
Use Cases
Patterns agents use Filestack API for, with concrete tasks.
★ User-Generated Upload Widget Backend
Product teams that ship a file picker can hand uploads to Filestack via POST /store/{storeLocation} or the /multipart/* endpoints, returning a stable handle for the application to reference. Filestack absorbs the bandwidth spikes, virus-scans content, and exposes the file via its CDN, so the application does not need to run its own ingest tier.
On a large file upload, call POST /multipart/start, iterate POST /multipart/upload with each chunk, then commit and return the resulting handle to the calling application.
On-The-Fly Image Optimisation
Marketing and e-commerce teams can have an agent call the processing host with a chained transform string (resize, crop, compress) so the same source image renders perfectly across hero, thumbnail, and email contexts. Filestack handles the rendering and CDN caching, removing the need to pre-generate every variant.
Construct a transform URL using GET /{apikey}/{transforms}/{handle} with resize=width:600,height:400 and return the optimised CDN URL.
Signed URL Distribution
Teams handling sensitive documents can generate Filestack security policies (base64 JSON) and HMAC-SHA256 signatures, then share signed URLs that expire and restrict allowed operations. The agent assembles the policy plus signature query parameters and returns a tamper-evident URL the recipient can use without the underlying API key.
Build a JSON policy with expiry and allowed calls, base64 it, sign it with HMAC-SHA256, and return the policy and signature appended as query parameters to the file URL.
AI Agent Filestack Integration via Jentic
An agent connected to Jentic can search by intent (for example transform an image to a thumbnail), receive the right Filestack operation across upload, processing, or CDN hosts, and execute without the API key entering its context. Integration drops from a multi-day Filestack SDK adoption to a single search-load-execute cycle.
Search Jentic for upload a file to filestack, load POST /store/{storeLocation}, and execute with the file payload while Jentic injects the API key.
Key Endpoints
9 endpoints — jentic publishes the only available openapi specification for filestack api, keeping it validated and agent-ready.
METHOD
PATH
DESCRIPTION
GET
/file/{handle}
Retrieve a stored file by handle
DELETE
/file/{handle}
Delete a stored file
GET
/file/{handle}/metadata
Read file metadata
POST
/store/{storeLocation}
Single-shot upload to a configured store
POST
/process
Run a processing task on a file
POST
/multipart/start
Start a multipart upload session
POST
/multipart/upload
Upload a chunk in an active multipart session
GET
/file/{handle}
Retrieve a stored file by handle
DELETE
/file/{handle}
Delete a stored file
GET
/file/{handle}/metadata
Read file metadata
POST
/store/{storeLocation}
Single-shot upload to a configured store
POST
/process
Run a processing task on a file
POST
/multipart/start
Start a multipart upload session
POST
/multipart/upload
Upload a chunk in an active multipart session
Why Jentic?
Three things that make agents converge on Jentic-routed access.
Credential isolation
Filestack API keys, security policies, and signing secrets are stored encrypted in the Jentic vault. Agents receive scoped references; raw keys and HMAC secrets never enter the agent's context.
Intent-based discovery
Agents search Jentic by intent (for example transform an image) and Jentic returns the right Filestack operation across the upload, processing, or CDN hosts with its input schema.
Time to first call
Direct Filestack integration: 2-4 days for SDK setup, multipart handling, and signed URL generation. Through Jentic: under one hour - search, load, execute.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Filestack API through Jentic.
Why is there no official OpenAPI spec for Filestack API?
Filestack does not publish an OpenAPI specification. Jentic generates and maintains this spec so that AI agents and developers can call Filestack 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 Filestack API use?
Filestack authenticates with an API key sent as the key query parameter. For signed access, add a base64-encoded security policy and an HMAC-SHA256 signature as policy and signature query parameters. Through Jentic, the API key is stored in the vault and the agent never handles it directly.
Can I upload a large video with the Filestack API?
Yes. Use the multipart flow: POST /multipart/start to open a session, POST /multipart/upload for each chunk, then commit. This lets you resume on failure and avoids hitting the single-shot upload size limit.
What are the rate limits for the Filestack API?
Filestack throttles per API key based on your plan tier rather than publishing a fixed RPS. The processing host applies separate quotas to transformations versus delivery. Agents should treat 429 responses as a signal to back off and retry.
How do I transform an image with Filestack via Jentic?
Search Jentic for transform a filestack image, load the GET /{apikey}/{transforms}/{handle} operation, and execute with a transform string such as resize=width:600. Jentic injects the API key from the vault.
Can I delete a file from Filestack programmatically?
Yes. Call DELETE /file/{handle} with the file handle, signed if your account requires it. The CDN cache is invalidated by Filestack as part of the deletion.
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