Shadow vs Palo Alto AI Access Security — open-source alternative for AI APIs
Palo Alto Networks AI Access Security, delivered through Prisma Access and Prisma Browser, discovers which AI apps employees use and applies data controls that block or allow prompts. Shadow is an open-source privacy layer that swaps sensitive values in AI API requests for realistic, reversible fakes and restores them in the response. Palo Alto governs AI use across a managed fleet; Shadow keeps the content of developer, agent and service traffic private without stopping the work.
At a glance
Section titled “At a glance”| Shadow | Palo Alto AI Access Security / Prisma Browser | |
|---|---|---|
| Open source / licence | Yes, Apache-2.0 | No, commercial |
| Deployment | Endpoint HTTPS proxy, gateway (/gw/<provider>/), Rust library | SASE (Prisma Access) and Prisma Browser |
| Protection method | Reversible realistic fakes from a persona; typed tokens for reports; optional redaction | Block or allow per policy; redaction mentioned only in a community blog |
| Restores responses | Yes, automatically | Not documented |
| Streaming | Yes, SSE and NDJSON with split-fake reassembly | Not documented for transformation |
| Tool calls | Yes, arguments restored locally; intent-aware for provider-hosted tools | Not documented |
| Files | DOCX, XLSX, PPTX masked in place; PDF to text; CSV, JSON, HTML | Not documented in the sources checked |
| Self-hosted | Yes, single binary, no account | No, cloud service and managed browser |
| Price model | Free | Licence bundle |
What Palo Alto does well
Section titled “What Palo Alto does well”- AI app discovery and risk scoring. Security teams get an inventory of AI apps in use, with risk attributes, so they can sanction some and restrict others.
- Enterprise browser control. Prisma Browser enforces data controls at the point where people type and paste, including on unmanaged or contractor devices that use the browser.
- Consistent enterprise DLP. The same DLP engine and data profiles used across Palo Alto’s platform apply to AI prompts.
- Central policy, logging and SOC integration. Decisions are logged and can feed the security operations stack, which helps with investigations and audit evidence.
- A broader AI security roadmap. Palo Alto announced an agreement to acquire Portkey to build the Prisma AIRS AI Gateway, which signals investment in API-level AI traffic as well as browser use.
Where Shadow is different
Section titled “Where Shadow is different”Translate instead of block
Section titled “Translate instead of block”Blocking a prompt stops a leak and stops the work. Shadow sends the request with every sensitive value it detects replaced by a realistic fake from a persistent persona: Acme GmbH becomes Zhilan Technology Co., Ltd., an IBAN keeps a valid checksum. The model answers normally and Shadow restores the real values.
Can Palo Alto restore values in streams and tool calls?
Section titled “Can Palo Alto restore values in streams and tool calls?”Public documentation does not describe that. Shadow restores fakes in SSE and NDJSON streams, even when split across events, and restores tool-call arguments on your machine so agents act on real values.
Intent-aware policy
Section titled “Intent-aware policy”Shadow treats an agent action, a bulk report, a code question and a conversation differently, using fakes, typed tokens like [PERSON_0007], kept recipients and provider-hosted action targets, or redaction. See intent-aware policy.
Files inside requests
Section titled “Files inside requests”Shadow masks DOCX, XLSX and PPTX uploads in place and turns PDFs into masked text. See file masking.
Open source, local, free
Section titled “Open source, local, free”No account and no telemetry. Detection runs locally, so plaintext prompts are not sent to a security cloud for inspection.
When should you choose Palo Alto?
Section titled “When should you choose Palo Alto?”- You already run Prisma Access or Strata and want AI controls in the same platform.
- You need discovery and governance of AI apps across a managed fleet.
- Your main concern is employees and contractors using AI in the browser.
- You need central reporting and SOC workflows.
When should you choose Shadow?
Section titled “When should you choose Shadow?”- You need to protect API calls to supported AI providers from developer tools, agents, CI runners and services.
- People must keep using AI with sensitive data, and answers must come back with real values.
- You need streaming, tool-call and Office-file support.
- You want an auditable, self-hosted, open-source control.
Using Palo Alto and Shadow together
Section titled “Using Palo Alto and Shadow together”- Keep Palo Alto for AI app discovery and browser-level controls on managed devices.
- Install Shadow on machines and services that call model APIs, using proxy mode or gateway mode.
- On those machines, exclude the AI API hosts Shadow intercepts from SSL decryption, or route Shadow’s outbound traffic through Prisma Access with
upstream_proxy. - Let Palo Alto decide which AI apps are allowed; let Shadow handle what goes into allowed requests.
How do they compare on accuracy?
Section titled “How do they compare on accuracy?”Palo Alto does not publish PII detection benchmarks on public datasets. Shadow’s benchmark publishes its datasets, label mappings and code.
Sources
Section titled “Sources”- Prisma Browser: GenAI prompt data controls
- Palo Alto Networks AI Access Security
- Report on the Portkey acquisition announcement
- Shadow vs Portkey
Last reviewed: 2026-10-31. Palo Alto Networks, Prisma and AI Access Security are trademarks of their owner; this comparison is based on public documentation as of the review date.
Frequently asked questions
Is Shadow a free alternative to Palo Alto AI Access Security?
For AI API traffic, partly. Shadow is free and open source and masks prompts with reversible fakes on the machines where it runs. Palo Alto AI Access Security is part of a commercial SASE platform that discovers and controls AI app use across a managed fleet. Shadow does not offer that fleet-wide visibility.
Can Palo Alto redact data in ChatGPT prompts?
Palo Alto's official Prisma Browser documentation describes data controls for GenAI prompts that block or allow. Redaction is described only in a community blog post we found, not in official product documentation, so treat it as unverified.
Does Palo Alto restore values in AI responses?
Reversible pseudonymisation is not documented. Shadow restores its fakes in responses, SSE streams and tool-call arguments locally.
How is Palo Alto AI Access Security priced?
It is sold as part of Palo Alto Networks licence bundles; public list prices are not published. Shadow is free under Apache-2.0.
Is Portkey part of Palo Alto now?
Palo Alto Networks announced an agreement to acquire Portkey in April 2026, positioning it as the Prisma AIRS AI Gateway. The closing date was not confirmed in sources we checked. See the Shadow vs Portkey page.