Company: FSLY
Filing Date: 2025-08-06
Form Type: S-8
Source: 0001517413-25-000222
Chunk: 0

Company: Fastly, Inc.
Filing Date: 2025-08-06
Form: S-8
Chunk 0
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<div align='center'>As filed with the U.S. Securities and Exchange Commission on August 6, 2025</div>

#### Registration No. 333-

### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION

#### Washington, D.C. 20549

#### FORM S-8

### REGISTRATION STATEMENT

#### UNDER

#### THE SECURITIES ACT OF 1933

#### Fastly, Inc.
<div align='center'>(Exact name of Registrant as specified in its charter)</div>

| Delaware                        |     | 27-5411834         |
| (State or other jurisdiction of 
 Incorporation or organization)  |     | -I.R.S. Employer   
 Identification No. |

#### 475 Brannan Street, Suite 300

#### San Francisco, CA 94107
<div align='center'>(844) 432-7859

(Address of principal executive offices) (Zip code)

Fastly, Inc. 2025 Employment Inducement Incentive Plan

(Full title of the plan)</div>

#### Tara Seracka

#### Chief Legal Officer

#### Fastly, Inc.

#### 475 Brannan Street, Suite 300

#### San Francisco, CA 94107
<div align='center'>(844) 432-7859

(Name and address of agent for service) (Telephone number, including area code, of agent for service)

Copies to:</div>

| Seth Gottlieb                
 Latham & Watkins LLP         
 140 Scott Drive              
 Menlo Park, California 94025 
 (650) 328-4600               |

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,”

“accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

| Large accelerated filer |     | ☒ |     | Accelerated filer         |     | ☐ |
| Non-accelerated filer   |     | ☐ |     | Smaller reporting company |     | ☐ |
|                         |     |   |     | Emerging growth company   |     | ☐ |

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended