Overview
A service account is an identity owned by your organization, not by a person. Its API keys let integrations, such as an OpenTelemetry collector, send traces to Fiddler. A personal API key acts as the person who created it, so it breaks or changes behavior when that person leaves or changes roles. Service account keys belong to the organization and carry only the permissions you grant. Use a service account when a workload, not a person, needs to send traces to Fiddler. Use a personal API key for your own scripts and notebooks. Fiddler service accounts are separate from cloud-provider service accounts, such as the Google Cloud service account you use for the LLM Gateway.Key Facts
These facts apply to service accounts created with Entire Org, the only choice available today.- A key from an Entire Org service account can send traces to every GenAI application in your organization. You can’t limit a key to one application.
- Fiddler shows the full key once. Anyone who has it can send trace data until you disable or revoke it.
- An Entire Org key can’t read your monitored data or change settings, and the LLM Gateway rejects it.
- Fiddler doesn’t send expiration emails, so an expired key stops ingestion without an email warning.
Prerequisites
- You are an Org Admin. Only Org Admins can create and manage service accounts.
- Fiddler has enabled service accounts for your Fiddler environment. Because this is a private preview, talk to your Fiddler contact before you move a production workload onto it.
- You are using the new Fiddler UI. To open it, add
preview.to the start of your Fiddler address, as described in the New Fiddler UI quick start.
How Service Accounts Work
Capabilities
In the create dialog, Capabilities has two parts. The Entire Org or Specific Projects choice sets where the service account applies. The capability checkboxes, such astraces:ingest, set what it can do.
Entire Org is the only choice available today, and Specific Projects shows as coming soon.
A capability is something a service account is allowed to do.
A service account can’t send traces until you grant it the traces:ingest capability, and its keys can use only the capabilities it has.
traces:ingest is the only capability today.
API Keys
Each service account can have 10 API keys by default.Create a Service Account
Open Service Accounts

The Service Accounts page lists every service account in your organization.
Open the Create Dialog
Name the Service Account
otel-collector-prod.
Names start with a letter and can contain letters, digits, spaces, hyphens, and underscores (up to 128 characters).
Optionally, add a Description, such as the team that owns the integration.Grant a Capability
traces:ingest.
Entire Org with traces:ingest: the resulting keys can send traces to every application in your organization.
Create
<workload>-<environment>.
Create an API Key
Open the Service Account

The detail page shows each key's status, Key Suffix, and expiration. Keys that expire within 30 days show Expiring Soon.
Name the Key
Choose an Expiration

The Create API Key dialog with a name and an expiration selected.
Copy the Key

Copy the key now. Fiddler can't show it again.
Send Traces with a Service Account Key
Use the complete key, starting withfks_, in place of the access token in the OpenTelemetry quick start:
fiddler-application-id header.
The key doesn’t choose the application.
To send to several applications with one key, see multi-application trace routing.
To confirm that it works, send a test trace and check that it appears in the application in Fiddler.
If it doesn’t, see Troubleshooting.
Manage Service Accounts
Changes usually apply on the next request. Allow up to 5 minutes for a disable or revoke to take full effect. With multi-application trace routing, allow up to 10 minutes by default.Rotate an API Key
Rotate keys before they expire, or on a regular schedule.Create a New Key
Update Your Integration
Disable the Old Key
Revoke the Old Key
revoke, and click Revoke API Key.Respond to a Leaked Key
Add thefks_ prefix to your secret-scanning rules to catch leaks early.
A leaked key can read server information (version, feature flags, organization name) and list your organization’s application IDs, but it can’t read your monitored data.
If a key might have leaked, act right away:
- Disable the exposed key. If you don’t know which key leaked, disable the service account instead.
- Create a new key and put it in your integration. A new key doesn’t work while its service account is disabled.
- If you disabled the service account, first disable every older key on it. Enabling a service account restores every key that isn’t disabled on its own, including the leaked one. Then enable the service account.
- Revoke the exposed key.
- Review recent traces in your applications for data you didn’t send.
Change a Service Account
Open the service account and click Edit. You can change the name, the description, and the capabilities, then click Save. A capability change applies to all of the service account’s keys. A service account with no capabilities can’t send traces.Disable or Enable a Service Account
You can’t delete a service account. To stop one, disable it: all of its keys stop working. Enabling it again restores the keys that are still active and unexpired. Use the service account’s row menu on the Service Accounts page, or the button on its detail page. Select Disable or Enable, then confirm.Change a Key’s Status
Use the ⋯ menu on the key’s row.Limitations
- Entire Org is the only choice. Limiting a service account to specific projects isn’t available yet.
traces:ingestis the only capability.- Service account keys can’t call the REST API or the Fiddler Python client, except to connect and send traces.
- A service account key can only send traces. SDK features that call other Fiddler APIs, such as
normalize_multimodal=Truein the Fiddler OpenTelemetry SDK, are rejected with 403 Forbidden, and the SDK keeps the content inline.
Troubleshooting
Related Resources
- OpenTelemetry Quick Start - Send your first trace
- Multi-Application Trace Routing - Send to several applications with one key
- API Keys - Manage your personal API keys
- Role-Based Access Control - Understand user roles and permissions
- Feature Maturity Definitions - What private preview means