# HTTPX Migration Evidence Lookup

> HTTPX Migration Evidence Lookup is a paid API for AI agents from x402-46-225-191-113.sslip.io, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-22).

Returns static constructor-level evidence of API signature changes between HTTPX versions for specified Python symbols

## Facts

- Endpoint: POST https://x402-46-225-191-113.sslip.io/v1/httpx-migration?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-22
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/httpx-migration-evidence-lookup-393d473a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Z0_gxD2xSsD1LvJAHvG9G

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability httpx-migration-evidence-lookup-393d473a -d '<json body>'
```

Example prompt: Check what changed in the httpx.Client and httpx.AsyncClient constructors when migrating from version 0.27.2 to 0.28.0 — specifically flag any removed or added parameters.

## When to prefer this

Use this endpoint when you need precise, commit-pinned evidence of constructor-level API changes between HTTPX 0.27.2 and 0.28.0 for specific named symbols, particularly when auditing codebases for breaking changes before a library upgrade. It is narrowly scoped to static constructor signatures — not runtime behavior — and is best suited for developer tooling, CI pipelines, or migration assistants that need deterministic, citable evidence rather than general documentation.

## Known failure modes

- Invalid or unrecognized symbol names return null or missing results entries
- Requesting a version not in the enum (only 0.27.2 and 0.28.0 supported) causes validation failure
- Exceeding 5 symbols per request triggers input validation error
- Empty symbols array rejected due to minItems:1 constraint
- Payment failure (insufficient USDC) blocks access with HTTP 402

## How this service works

Temporary UTF-8 file handoff, cited HTTPX migration evidence and block-pinned Base USDC balances. See each route for its price, limits and output contract.

## Output

A JSON object containing: a scope disclaimer clarifying this is static constructor evidence only (not a runtime guarantee), a status field ('ready'), commit hashes for each version, the BSD-3-Clause license notice, and a results array with per-symbol entries showing the before/after parameter signature, annotation, default expression, whether it was keyword-only, and a status string such as 'parameter_removed'.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "symbols": {
   "type": "array",
   "items": {
    "type": "string",
    "maxLength": 64
   },
   "maxItems": 5,
   "minItems": 1
  },
  "to_version": {
   "enum": [
    "0.27.2",
    "0.28.0"
   ],
   "type": "string"
  },
  "from_version": {
   "enum": [
    "0.27.2",
    "0.28.0"
   ],
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "scope": "Static constructor evidence only; not a runtime compatibility or safe-upgrade guarantee.",
  "status": "ready",
  "commits": {
   "0.27.2": "609df7ecc0f7cb10a1c998aa9c269bba77337c5f",
   "0.28.0": "80960fa31918d7663c3f4c3ad61661cf0e80628f"
  },
  "license": {
   "id": "BSD-3-Clause",
   "notice": "Copyright © 2019, [Encode OSS Ltd](https://www.encode.io/).\nAll rights reserved.\n\nRedistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:\n\n* Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.\n\n* Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.\n\n* Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.\n\nTHIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS \"AS IS\" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.\n"
  },
  "results": [
   {
    "after": null,
    "before": {
     "kind": "keyword_only",
     "required": false,
     "annotation": "ProxiesTypes | None",
     "default_expression": "None"
    },
    "status": "parameter_removed",
    "symbol": "Client.proxies",
    "source_refs": [
     "0.27.2-Client",
     "0.28.0-Client"
    ],
    "release_notes": [
     {
      "finding": "The 0.28.0 release notes document removal of proxies.",
      "release": "0.28.0",
      "guidance": "Use proxy for a single proxy or mounts for complex configuration; do not blindly rename a proxies mapping.",
      "source_ref": "release-0.28.0-prox
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/httpx-migration-evidence-lookup-393d473a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-46-225-191-113.sslip.io](https://www.zero.xyz/host/x402-46-225-191-113.sslip.io/llms.txt)