Google IAM Service Account Credentials API
Browse all Google APIs35
AI ReadinessNon-Ready (F)35/100
Official vendor OpenAPI document · agent-readyIdentity AuthAuthenticationoauth25 EndpointsREST
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://jentic.com/install.sh?src=apis&api=%2Fapis%2Fgoogleapis.com%2Fiam-credentials" | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fgoogleapis.com%2Fiam-credentials" | 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
Jentic AI Readiness Score
This API is usable in Jentic One now. Its AI-readiness score against Jentic's framework shows where it stands today and where improvements would make it even easier for agents to use.
I
IAM Service Account Credentials API
- Non-Ready (F)35/100
72
Foundational Compliance56
Developer Experience & Jentic Compatibility13
AI-Readiness & Agent Experience94
Agent Usability63
Security60
AI DiscoverabilityPowered by JenticScoring Framework 1.0.0 | Scoring Engine 0.4.0
Show dimension breakdown
72
Foundational Compliance
Base layer of spec validity and structural soundness.
Grade: A-Signals: 4
88%
Lint Results
Aggregated quality score from linter diagnostics, weighted by severity.
100%
Resolution Completeness
Percentage of `$ref` references that resolve successfully.
0%
Specification Validity
Checks whether the API description parses successfully and conforms to its declared specification (e.g., OpenAPI).
100%
Structural Integrity
Structural correctness score based on schema issues using logarithmic dampening.
56
Developer Experience & Jentic Compatibility
Clarity, completeness, and ingestion readiness for developers and tooling.
Grade: CSignals: 4
0%
Example Density
How richly the API is illustrated with examples.
100%
Example Validity
Percentage of examples that conform to their schemas.
25%
Response Coverage
Percentage of operations with complete response definitions (success, client error, server error).
100%
Tooling Readiness
Health of API ingestion, bundling, and resolution within Jentic pipelines.
13
AI-Readiness & Agent Experience
Semantic breadth, depth, and agent comprehension for AI systems.
Grade: FSignals: 4
54%
Description Coverage
Coverage of descriptions across API elements.
0%
Error Standardization
Coverage of RFC 9457 Problem Details for error responses.
0%
OperationId Quality
Coverage, uniqueness, and casing consistency of operationIds for AI inference.
0%
Summary Coverage
Coverage of summaries across operations/tags/info.
94
Agent Usability
Functional utility, complexity comfort, and AI orchestration readiness.
Grade: A+Signals: 1
94%
Complexity Comfort
Agent comfort level based on API operational and structural complexity.
63
Security
Trust, risk posture, and security compliance.
Grade: B-Signals: 1
62%
Authentication Strength
Average quality of security schemes based on authentication method strength (weakest link for OAuth2).
60
AI Discoverability
Findability, semantic richness, and reasoning readiness.
Grade: B-Signals: 1
60%
Descriptive Richness
Clarity and depth of descriptions across API elements.
Score it yourself
Every API in the directory is allowlisted, so you can re-score it with no key required.
npx @jentic/api-scorecard-cli score <openapi-url>Why Jentic?
What agents get from Jentic-routed access to this vendor.
Setup
Wiring the IAM Service Account Credentials API by hand means configuring the caller's OAuth2, refreshing tokens, and building the impersonation request for each target service account yourself. Through Jentic you install once, import the IAM Service Account Credentials API from the API Directory, store the credential once, and your agent calls it.
Permission scoping
The target service account travels in the URL path (/v1/{name}:generateAccessToken), so a rule can pin your agent to one service account: it mints tokens or signatures for that account and nothing else. You choose the operations it may call, so if you allow only generateAccessToken the agent cannot signBlob or signJwt unless you add them.
Credential isolation
Your calling principal's credential is stored once, encrypted, by your own Jentic One instance and injected at execution time as a short-lived token. Neither the caller's credential nor any target service account's private key enters the agent's prompt, logs, or context.
Intent-based discovery
Agents search Jentic by intent such as 'mint service account access token' or 'sign a jwt as a service account', and Jentic returns the matching operation with its request body schema so the agent picks the right method without browsing the reference docs.
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.
Can I limit what my agent is allowed to do with the Google IAM Credentials API?
Yes. Because you run Jentic One yourself, your own rules decide which operations and credentials the agent may use. The target service account travels in the URL path of each call, so you can pin the agent to a single account and let it mint tokens or signatures only for that one. You also choose the operations it may call, so if you allow only generateAccessToken the agent cannot reach signBlob, signJwt, or generateIdToken unless you add them.
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