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File Infrastructure That Holds at Any Scale

Reliable uploads on every network, at every volume. Filestack delivers clean files to your users on WiFi, LTE, and degraded connections alike.

99.9%
Upload success rate
100K+
Applications powered
Global
CDN via Fastly
Trusted by teams at
SendGrid logo with stylized gray text and overlapping square shapes on the left.
LinkedIn logo followed by the word SlideShare in gray text on a light background.
The word teachable is written in all lowercase, sans-serif letters with a colon between teach and able, in a light purple color on a light background.
A gray Airtable logo featuring a geometric cube design to the left of the word Airtable in bold, modern font.
5 guarantees
  • 99.99% upload success rate
  • Fastly global CDN on every delivered file
  • 20+ upload sources behind one endpoint
  • SOC 2 Type II compliance, with encryption in transit and at rest
  • Every device and every network condition, including 2G

What Reliable File Infrastructure Protects

Three things your team is otherwise spending.

01

Senior Engineer Hours Back on Product Work

Large-file timeouts, mobile network drops, format edge cases. Filestack owns those, so your engineers stay on the roadmap.

02

Users Who Finish the Action They Came For

Upload friction is silent churn, and it peaks at the moment a user has committed. The transfer stays alive through it.

03

Months of Build Time, Available on Day One

Resumable uploads, multi-source ingestion, CDN delivery, format handling. Each a multi-month build, all four working on day one.

Built for the Conditions Your Users Actually Experience

The Content Ingestion Network handles reliability at every layer, from the upload handshake to the edge.

Resumable Upload

Parts that already landed are retained, so the transfer continues from where it stopped rather than starting over.

transferchunked multipart, concurrent parts
retryFsRetryConfig
abortcancel tokens
on failureupload.error, body + headers + code
reportingSentry, with diagnostic tags

Filestack Upload →

Content Ingestion Network

Routed to the Nearest Healthy Node

The closest ingestion point for each upload, with the Picker on top pulling from 20+ cloud sources.

Scale Elastic Processing

Capacity scales to absorb the spike, so a release ships on your schedule rather than your capacity planning.

Global CDN Delivery

Fastly serves from the nearest edge, with responsive variants through auto_image.

Automatic Failover

Traffic reroutes to a healthy node in milliseconds. The client keeps its connection.

Redundant Storage

Geographic redundancy, so files survive a single-region event.

Watch the Network Absorb Real World Conditions

Pick a scenario and see how Filestack keeps the upload alive.

Resumable Upload Over a Dropping 3G Link

The connection drops at 60%. Every chunk already received is retained, the transfer continues from where it stopped, and your application receives one clean file.

How uploading works
How a resumed transfer works · illustration
Delivered before the drop Connection lost Delivered after resume
example filelaunch-clip.mp4 · 24.0 MB
network3G, weak
progress at drop60%
bytes re-sent0
files your app received1, complete

An Ingestion Node Degrades Mid-Traffic

A degrading node leaves rotation in milliseconds and in-flight uploads reroute to the next healthy one, with the client untouched.

Content Ingestion Network
01
Upload
Client sends a chunk
02
Reroute
Degraded node dropped
03
Ingest
Next healthy node
04
Store
Geographic redundancy

The reroute is the only step that changed. Your application receives the same handle either way.

Ten Times Normal Volume, Absorbed

Capacity scales with the incoming volume and returns on its own once the spike passes. Uploads keep completing on the first attempt through the peak.

Plans and volume
How a volume spike is absorbed · illustration
00:0006:0012:0018:00Now

Illustrative, not a measured trace. The bars in full orange are the spike hours: no throttling and no queue backlog through the peak.

Performance That Holds Under Pressure

Sized for the peak rather than the average, in every layer the file passes through.

  • Resumable uploads on any network. The transfer picks up exactly where it left off.
  • Elastic scale for traffic spikes. Ten times normal volume, absorbed at full speed.
  • Fastly CDN edge delivery. Served from the node closest to each user, in every market.
  • Mobile-first reliability. Uploads complete on the user’s first attempt.
Delivery path · what you do not have to run
CDNFastly, Anycast routing
EdgeGlobal points of presence
Origins to keep in sync1
Per-region deployments0
Sizes served from one handleEvery one you ask for

Anycast routing sends each request to the nearest point of presence, so one origin serves every market.

“Surgery Supporters record quick videos on their phones to send encouragement to patients. The platform needed guaranteed delivery across all network conditions and devices to preserve these meaningful moments.“
Steve Birnhak, COO, Ready Set Recover

What Teams Gained by Moving to Filestack

Healthcare · mobile

Ready Set Recover

100%
Mobile upload success in beta

A supporter video that misses the operation cannot be sent again. They reached patients on whatever network the supporters were on.

Read the case study →

Ed-tech · scale

Teachable

1,000
Videos uploaded per day by teachers

More than 125,000 videos to date, absorbed without a dedicated infrastructure team or a custom upload pipeline.

Read the case study →

Marketplace · CTO

Grailed

Removed
The largest bottleneck in the app

In the CTO’s own description, the largest bottleneck in the entire application. Handing it off returned the team to the product.

Read the case study →

The Mechanisms, Written Out

For the engineers who have to defend the decision internally.

Development

Handling Large Files in Mobile Upload on Slow Connections

3G, tower handoffs, backgrounded apps. Chunked transfer and resumable mechanics, and what the CIN absorbs. Read the article →

CDN

File Delivery 101 for Faster CDN Downloads at Scale

How edge caching works, why origin-served files fall apart under load, and what points of presence buy you. Read the article →

Production

File Upload API Patterns for Production-Ready Apps

Auth flows under load, webhook delivery guarantees, resumable edge cases, and architecting for scale early. Read the article →

Frequently Asked Questions

What happens to an upload when the connection drops?

The upload is chunked, so parts that already reached an ingestion node are retained. When the connection returns, the transfer resumes from the last completed part. The user sees a progress bar that pauses and continues, and your application receives one clean file.

What is the Content Ingestion Network?

The Content Ingestion Network, or CIN, is the routing layer between the uploading device and storage. It sends each upload to the nearest healthy ingestion point and reroutes if one degrades, while the client keeps its connection.

Do I need to do anything to handle a traffic spike?

Nothing. Filestack scales ingestion and processing capacity automatically, so a launch or a viral moment that multiplies your normal upload volume is absorbed without provisioning work, queue tuning, or throttling on your side.

Which CDN delivers the files?

Files are delivered through Fastly, which uses Anycast routing across a global network of points of presence. The same handle serves every region and every size, so there is one origin to maintain.

How long would this take to build in house?

Resumable uploads, multi-source ingestion, geographic redundancy, and CDN delivery are each multi-month builds, and keeping them working across every device and network is permanent maintenance rather than a one-time project.