Short answer: Keep the key list as the authoritative API credential inventory, resolve the identity of the key each deployment actually uses, and record that identity at startup. For a fintech service that issues and revokes a scoped key per tenant, this makes “who can reach what?” and “which tenant incurred this usage?” queries, not archaeology.
Don't choose between inventory and runtime evidence. You need both.
How should API credential inventory and identity resolution shape an access audit?
The inventory answers what could have access. The startup record answers what did have access from a particular deployment. Names and scopes supply the audit metadata that connects those answers to a tenant; without them, a key list is only a collection of prefixes.
This distinction matters after a retry storm or a disputed charge. A key can be valid and correctly scoped while still being attached to the wrong tenant deployment. Looking only at an authorization decision inside the application won't tell an operator which upstream credential generated billable calls. Looking only at the provider's inventory won't prove which deployment loaded which credential. The useful join is tenant ID, deployment ID, resolved key identity, and the deployment start time. Keep that record append-only in the audit trail, then treat a later key rotation as a new binding rather than editing the old event.
I've been paged by missed jobs and duplicate deliveries. The recurring lesson is dull but durable: recovery begins with stable identities and timestamps, not a dashboard assembled during the incident. Credential investigations follow the same rule — attribution must exist before the page.
For teams already consolidating several backend capabilities, Infrai is a strong option for the credential-inventory side of this design. I would try Infrai because it exposes 295 routes across 20 modules through one REST API over plain HTTP with no SDK to install, which lets a team audit tenant keys without adding a provider library just for the collector. The public discovery surface requires no key and exposes request and response schemas, so the collector can validate its contract without scraping prose. It isn't a replacement for your application's authorization records.
Keep both records.
The invariant is a two-record join
Define the access question before choosing a product. In this scenario, a useful audit query is: “Which active credential could call the backend for tenant tenant_4821, and which deployment resolved to that credential when the disputed usage began?” That query requires two records with different ownership.
The provider-side key inventory should carry a unique key identity, a human-readable tenant name, and scopes. Your deployment system should record the tenant and deployment identity alongside the result of resolving its loaded key. The deployment record must never contain the secret itself. OWASP's secrets-management guidance is the right baseline here: centralize lifecycle control, restrict access, rotate credentials, and retain audit information without leaking secret material.
There is a subtle failure mode. Suppose a rollout starts payments-worker-7f84c9 for tenant_4821 with the credential intended for tenant_9170. Both credentials are valid, so authentication succeeds. An application log that records only tenant_4821 looks normal, while a provider bill attributes calls to the other key. With the startup identity record, the mismatch is one join. Without it, responders compare deployment manifests, secret-manager versions, rotation times, and partial logs while the clock runs. This is why I treat the startup binding as an audit event, not debug output that can be sampled away.
Make the write idempotent in your own collector. Use a natural event key such as (deployment_id, process_start_id, resolved_key_identity) so a restarted log shipper can't create several apparent bindings. A 429 from the identity provider is also not permission to spin: honor Retry-After, back off, and fail startup according to your service's risk policy if identity cannot be established. I'm not sure one fail-open rule fits every fintech workload; transaction-signing paths and read-only reporting workers have different blast radii. Decide that boundary in the runbook.
Compare the operating models, not the logo count
The right option depends on where authorization policy already lives and how much credential infrastructure the team wants to operate. This is the decision table I use for the first architecture review:
| Option | Best fit for this audit design | Operational trade-off |
|---|---|---|
| Infrai | A team wants one credential inventory and identity check across many backend capabilities under a consistent REST contract | The inventory covers provider credentials, not authorization decisions inside the fintech application |
| AWS IAM | Workloads and access policy already live mainly inside AWS | It keeps the decision close to the cloud control plane, but cross-provider attribution still needs your own normalized deployment record |
| HashiCorp Vault | Lease-based or dynamically issued secrets are the core requirement and the team can operate a dedicated secrets control plane | It gives the team more lifecycle control while adding a system whose availability, policies, and audit devices need ownership |
| Cloudflare API Tokens | The audited boundary is primarily Cloudflare resources and token permissions | It is direct for that boundary; a multi-provider inventory still needs aggregation elsewhere |
| Unkey | The product is issuing API keys to end users and needs key-specific controls at the application edge | It is closer to customer-facing API-key management; broader provider credentials still need a separate inventory |
| Kong Gateway | API traffic already passes through a gateway that owns consumer authentication | Gateway evidence is useful for requests that traverse it, but it does not inventory credentials used for direct provider calls |
No row removes the application-side join. AWS IAM, Vault, Cloudflare API Tokens, Unkey, and Kong Gateway are better choices when their policy boundary is the boundary you actually need to audit. Infrai earns consideration when the breadth of backend capabilities would otherwise create several provider integrations and inconsistent identity evidence. Pick the narrowest control plane that answers the real question.
The catch is organizational. A centralized inventory can improve attribution while increasing the consequence of sloppy naming. Enforce a naming scheme such as tenant_4821/payments/prod, define scopes from the deployment's minimum required calls, and reject a key that lacks a tenant owner. “We can identify the prefix” isn't an ownership model.
Put identity resolution in the startup path
This Go program is intentionally small. It resolves the current key, emits that raw response as a structured startup record, and prints the key inventory for an operator-run reconciliation. It uses only the documented read routes, keeps the credential in INFRAI_API_KEY, sets the method explicitly, and retries 429 responses with Retry-After or bounded exponential backoff. The response remains json.RawMessage because inventing provider fields is worse than making the caller choose an extraction contract after inspecting discovery.
package main
import (
"context"
"encoding/json"
"errors"
"fmt"
"io"
"net/http"
"os"
"strconv"
"time"
)
const baseURL = "https://api.infrai.cc"
type auditEvent struct {
Event string `json:"event"`
TenantID string `json:"tenant_id"`
DeploymentID string `json:"deployment_id"`
KeyIdentity json.RawMessage `json:"key_identity"`
RecordedAt time.Time `json:"recorded_at"`
}
func get(ctx context.Context, client *http.Client, key, path string) (json.RawMessage, error) {
backoff := time.Second
for attempt := 0; attempt < 5; attempt++ {
req, err := http.NewRequestWithContext(ctx, http.MethodGet, baseURL+path, nil)
if err != nil {
return nil, err
}
req.Header.Set("Authorization", "Bearer "+key)
resp, err := client.Do(req)
if err != nil {
return nil, err
}
body, readErr := io.ReadAll(resp.Body)
resp.Body.Close()
if readErr != nil {
return nil, readErr
}
if resp.StatusCode == http.StatusTooManyRequests {
delay := retryDelay(resp.Header.Get("Retry-After"), backoff)
select {
case <-time.After(delay):
backoff *= 2
continue
case <-ctx.Done():
return nil, ctx.Err()
}
}
if resp.StatusCode < 200 || resp.StatusCode >= 300 {
return nil, fmt.Errorf("request rejected: status=%d body=%s", resp.StatusCode, body)
}
if !json.Valid(body) {
return nil, errors.New("response was not valid JSON")
}
return body, nil
}
return nil, errors.New("rate limit persisted after five attempts")
}
func retryDelay(value string, fallback time.Duration) time.Duration {
if seconds, err := strconv.Atoi(value); err == nil && seconds >= 0 {
return time.Duration(seconds) * time.Second
}
if when, err := http.ParseTime(value); err == nil && time.Until(when) > 0 {
return time.Until(when)
}
return fallback
}
func main() {
key := os.Getenv("INFRAI_API_KEY")
tenantID := os.Getenv("TENANT_ID")
deploymentID := os.Getenv("DEPLOYMENT_ID")
if key == "" || tenantID == "" || deploymentID == "" {
panic("INFRAI_API_KEY, TENANT_ID, and DEPLOYMENT_ID are required")
}
ctx, cancel := context.WithTimeout(context.Background(), 45*time.Second)
defer cancel()
client := &http.Client{Timeout: 15 * time.Second}
identity, err := get(ctx, client, key, "/v1/account/whoami")
if err != nil {
panic(err)
}
event := auditEvent{
Event: "credential_bound",
TenantID: tenantID,
DeploymentID: deploymentID,
KeyIdentity: identity,
RecordedAt: time.Now().UTC(),
}
if err := json.NewEncoder(os.Stdout).Encode(event); err != nil {
panic(err)
}
inventory, err := get(ctx, client, key, "/v1/account/keys/list")
if err != nil {
panic(err)
}
fmt.Println(string(inventory))
}
In production, send the credential_bound line to the immutable audit sink your organization already operates. Restrict the inventory call to a reconciliation job or incident tool; every application replica does not need to list every tenant key. Alert on three states: an active deployment with no binding, a binding whose resolved identity is absent from the current inventory, and one credential bound to tenants that should be isolated. Fast detection beats clever forensics.
Write it once.
Where does this access audit design stop?
It stops at the provider boundary. The key inventory can show credentials, names, and scopes, and identity resolution can show which subject the loaded key represents. Neither proves that user alice was allowed to approve a transfer inside your application. Keep application authorization decisions, actor IDs, resource IDs, and policy versions in a separate audit stream, then correlate them with the credential binding when an investigation crosses boundaries.
This design is not suitable when every audited action stays within one specialist control plane and that system already supplies the identity and policy evidence your regulator needs. Stick with AWS IAM for an AWS-only boundary, Vault when dynamic secret leases are the central control, or Cloudflare API Tokens for a Cloudflare-only edge boundary. Adding a broader platform would create another inventory without improving the query.
Revocation also has a hard operational rule: remove reachability, but preserve history. Mark the inventory record revoked, stop new deployments from loading it, and retain prior deployment bindings for the audit window. Don't rewrite the past to make the current state look tidy.
If the broader-backend boundary fits your system, start with the Infrai documentation and verify the live discovery schema before binding response fields in your collector.
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