Google IAM Service Account Credentials API
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For Agents
Mint short-lived OAuth access tokens, ID tokens, signed JWTs, or signed blobs in the identity of a Google Cloud service account, without distributing private keys.
Use for: Mint a short-lived access token for a service account, Generate an ID token for service-to-service authentication, Sign a JWT as a Google Cloud service account, Sign a binary blob without exposing the service account key
Not supported: Does not create service accounts, manage IAM bindings, or rotate keys — use for minting short-lived credentials for existing service accounts only.
The IAM Service Account Credentials API mints short-lived credentials for Google Cloud service accounts. A caller with iam.serviceAccountTokenCreator on a target service account can request a 1-hour OAuth 2.0 access token, an OpenID Connect ID token, a signed JWT, or a signed binary blob, all issued in the target service account's identity. This is the standard mechanism for service-account impersonation, workload identity federation, and key-less signing on Google Cloud, replacing the practice of distributing long-lived service-account JSON keys.
Install Jentic One Beta
Connect the IAM Service Account Credentials API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the IAM Service Account Credentials 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 IAM Service Account Credentials API.
Generate a 1-hour OAuth 2.0 access token in the identity of a target service account
Mint an OpenID Connect ID token with a custom audience for service-to-service authentication
Sign a binary blob using the target service account's private key without exposing the key
Sign a JWT payload as the target service account for use with Google or third-party services
List allowed locations for a service account to support residency-aware credential issuance
Use Cases
Patterns agents use IAM Service Account Credentials API for, with concrete tasks.
★ Key-less Service Account Impersonation
Platform teams remove long-lived service-account JSON keys by giving callers iam.serviceAccountTokenCreator on a target service account and using POST :generateAccessToken to mint a 1-hour OAuth token at call time. The caller uses the token for the immediate Google API call, then discards it. This dramatically reduces the blast radius of credential leaks compared with distributing JSON keys.
Call POST /v1/projects/-/serviceAccounts/etl-runner@my-project.iam.gserviceaccount.com:generateAccessToken with a 1-hour lifetime and the cloud-platform scope, and return the resulting accessToken.
ID Token for Cloud Run-to-Cloud Run Auth
When one Cloud Run service calls another, it mints an OIDC ID token via :generateIdToken with the target service URL as audience and presents it on the outbound request. The receiving service validates the token's audience and issuer. This pattern works identically across Cloud Run, Cloud Functions, and IAP-protected backends.
Call POST /v1/projects/-/serviceAccounts/svc@p.iam.gserviceaccount.com:generateIdToken with audience https://api.example.run.app and includeEmail true, and return the idToken.
Signed JWT for Third-Party Services
Integrations that need to authenticate to a third-party service via signed JWT (e.g. AWS STS AssumeRoleWithWebIdentity, third-party APIs that accept Google service-account tokens) use :signJwt to sign a payload with the service account's private key. The API never returns the key, only the signed JWT, which is rotated automatically by Google.
Call POST /v1/projects/-/serviceAccounts/federated@p.iam.gserviceaccount.com:signJwt with a payload containing iss, sub, aud, and exp, and return the signedJwt.
AI Agent Just-in-Time Credentials
An AI agent acting on Google Cloud uses Jentic to call :generateAccessToken whenever it needs to access a downstream Google API. The agent never holds a long-lived service-account key; instead, it requests a 1-hour token in the identity of the right service account for the task. Jentic enforces who the agent is allowed to impersonate via vault scoping.
On behalf of agent role data-reader, call :generateAccessToken on bigquery-reader@p.iam.gserviceaccount.com with the bigquery.readonly scope and a 30-minute lifetime, then use that token to call BigQuery.
Key Endpoints
5 endpoints — the iam service account credentials api mints short-lived credentials for google cloud service accounts.
METHOD
PATH
DESCRIPTION
POST
/v1/{+name}:generateAccessToken
Mint a short-lived OAuth 2.0 access token in the identity of the service account
POST
/v1/{+name}:generateIdToken
Mint an OpenID Connect ID token with a custom audience
POST
/v1/{+name}:signBlob
Sign a binary blob using the service account's private key
POST
/v1/{+name}:signJwt
Sign a JWT payload as the service account
GET
/v1/{+name}/allowedLocations
List allowed locations for the service account
POST
/v1/{+name}:generateAccessToken
Mint a short-lived OAuth 2.0 access token in the identity of the service account
POST
/v1/{+name}:generateIdToken
Mint an OpenID Connect ID token with a custom audience
POST
/v1/{+name}:signBlob
Sign a binary blob using the service account's private key
POST
/v1/{+name}:signJwt
Sign a JWT payload as the service account
GET
/v1/{+name}/allowedLocations
List allowed locations for the service account
Why Jentic?
Three things that make agents converge on Jentic-routed access.
Credential isolation
The calling principal's OAuth credential lives in the Jentic vault. IAM Credentials calls mint short-lived target-service-account tokens at execution, so neither the caller's credentials nor the target service account's private key reach the agent runtime.
Intent-based discovery
Agents search 'mint service account access token' or 'sign jwt as service account' and Jentic returns the matching operation with its full request body schema, so the agent picks the right :generate* method without reading docs.
Time to first call
Direct integration: 0.5-1 day to wire IAM roles, OAuth client, and impersonation logic. Through Jentic: under 30 minutes — search, load, execute the right :generate* call.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using IAM Service Account Credentials API through Jentic.
What authentication does the IAM Credentials API use?
Google OAuth 2.0 with the cloud-platform scope. The calling principal must hold iam.serviceAccountTokenCreator on the target service account. Through Jentic the calling credential is stored encrypted and exchanged for a scoped access token at call time.
Can I generate a token without a service-account JSON key?
Yes. POST /v1/{+name}:generateAccessToken returns a 1-hour OAuth token issued in the target service account's identity, given that the caller has iam.serviceAccountTokenCreator. This is the recommended replacement for downloaded JSON keys.
What are the rate limits for the IAM Credentials API?
Google enforces per-project quotas on credential-generation endpoints. generateAccessToken and generateIdToken default to thousands of QPS but vary by region; signJwt and signBlob have separate quotas. Exact values are visible in Cloud Console quotas for the IAM Credentials API.
How do I impersonate a service account for one API call through Jentic?
Search Jentic with 'mint service account access token', load the POST /v1/{+name}:generateAccessToken operation, and execute with name set to projects/-/serviceAccounts/{email} and a body specifying scope and lifetime. Jentic returns an access token the agent can use immediately.
What is the difference between generateAccessToken and generateIdToken?
generateAccessToken returns an OAuth 2.0 access token used as the Authorization bearer to call Google APIs. generateIdToken returns an OIDC ID token used to authenticate to receivers like Cloud Run, Cloud Functions, or IAP, where the audience claim is checked against the target service URL.
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