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Head to head · Secrets store · October 2026 research run

Phase vs Pulumi ESC

Pulumi ESC scores 71.1 (BB) on agent readiness against Phase's 68 (B), and leads in 3 of 7 scored categories. Phase leads on reliability and transparency & trust. Both do secrets store.

PhasePhi Security Inc. · HTTP API B68/100#194 of 722 Pulumi ESCPulumi Corporation · HTTP API BB71.1/100#120 of 722

Which one, for what

Phase B

Good for Small teams that want an open-source secrets manager hosted in the EU or self-hosted, with coding agents kept away from values through the CLI.

Ahead on

  • Reliability, 91 against 60
  • Transparency & trust, 73 against 65

Also in its favour

  • Open source

Watch for

No OpenAPI document was found. The REST reference is prose with examples, covering 47 operations

Pulumi ESC BB

Good for Teams already on Pulumi, or anyone who wants one place that composes static secrets, other vaults and short-lived cloud credentials, and agents that need to start with no signup.

Ahead on

  • Schema & documentation, 82 against 58
  • Agent ergonomics, 75 against 56
  • Payments & pricing, 55 against 25

Also in its favour

  • Agent-ready, a grade of BB or better
  • Free to start without a card

Watch for

Audit logs, custom roles, team tokens, approvals and customer-managed keys need Pro ($400 a month) or Enterprise

Score by category

CategoryWeight this runPhasePulumi ESCEdge
Reliability16%209160Phase +31
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.25882Pulumi ESC +24
Agent ergonomics13%16.25675Pulumi ESC +19
Security & auth14%17.58379Phase +4
Payments & pricing10%12.52555Pulumi ESC +30
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88382Phase +1
Transparency & trust7%8.87365Phase +8
Negative events≤1500
Total68 · B71.1 · BB

Facts side by side

FactPhasePulumi ESC
KindHTTP APIHTTP API
VendorPhi Security Inc.Pulumi Corporation
Hosted endpointhttps://api.phase.devhttps://api.pulumi.com
TransportsHTTPHTTP
AuthOAuth or keyOAuth or key
PricingFreemiumFreemium
x402nono
LicenceMIT outside the ee/ directories, which are under the proprietary Phase Console Enterprise licenceProprietary service under Pulumi's Terms & Conditions. The Pulumi CLI, the ESC evaluator and the ESC SDKs are Apache-2.0
Read-only variant documentednoyes
llms.txtyesyes
Last release2026-10-042026-10-07
Terms last updated2025-10-06no date given
Privacy policy last updated2026-03-11no date given
Customer content may train modelsnot found in the textnot found in the text
Terms restrict automated accessyesnot found in the text
Terms restrict benchmarkingyesnot found in the text
Terms or service can change without noticenot found in the textyes
Arbitration or class-action waivernot found in the textnot found in the text
Popularity928 stars, 2.5k npm/wk, 235 PyPI/wk21k npm/wk, 54k PyPI/wk

Verdicts

Phase

Service account tokens can be minted with an expiry over the API, every secret read is logged, and the CLI redacts values when it detects an AI agent. No OpenAPI document or pagination was found in the reviewed documentation, and the Free plan keeps audit logs for 24 hours.

Pulumi ESC

An agent can start without a signup, because the Pulumi CLI creates a free ephemeral account that includes ESC, and the REST API has a public OpenAPI document. Audit logs, custom roles and approvals need the Pro edition at $400 a month, and no API rate limit was found in the reviewed documentation.

Before you call either

Phase

  1. Enable server-side encryption on the app before calling /v1/secrets. Without it the REST API cannot read or write that app's secrets
  2. Send Authorization: Bearer ServiceAccount <token> for a service account and Bearer User <token> for a personal access token. The token type is part of the header
  3. Stay under 120 requests a minute per account on Free and 240 on Pro, and wait the seconds in the retry-after header on a 429
  4. Treat a 409 on POST /v1/secrets as the key already existing at that path, and use PUT to change it. Rotating secrets reject PUT and DELETE
  5. Have a person run phase ai enable and choose masked values. The CLI blocks an agent from running phase ai enable or phase ai disable itself

Pulumi ESC

  1. Use pulumi env, not esc. The standalone CLI stopped at v0.26.0 and gets no security fixes
  2. Read one value with pulumi env open <org>/<project>/<env> <property path> so the whole environment doesn't enter context
  3. Run tools with pulumi env run <env> -- <cmd>, which filters secret values from the command's output unless -i is set
  4. Set PULUMI_ACCESS_TOKEN for the SDKs. From 0.14.0 they no longer read the CLI login on disk
  5. Send Authorization: token <token> and Accept: application/vnd.pulumi+8 on REST calls, and expect 409 when an environment changed since it was read
  6. Relay the claim link an agent account prints. The account goes read-only after 72 hours and locks after 30 days unclaimed

Questions

Which is better for AI agents, Phase or Pulumi ESC?

Pulumi ESC scores 71.1 (BB) on agent readiness against Phase's 68 (B), and leads in 3 of 7 scored categories. Phase leads on reliability and transparency & trust.

Do Phase and Pulumi ESC need an API key?

Both take an API key or an OAuth sign-in.

Can an agent call Phase and Pulumi ESC without installing anything?

Yes. Phase has a hosted endpoint at https://api.phase.dev and Pulumi ESC at https://api.pulumi.com.

Are Phase and Pulumi ESC open source?

Phase is open source (MIT outside the `ee/` directories, which are under the proprietary Phase Console Enterprise licence). No open-source release is listed for Pulumi ESC.

Other comparisons with Phase or Pulumi ESC

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