> ## Documentation Index > Fetch the complete documentation index at: https://docs.useselo.xyz/llms.txt > Use this file to discover all available pages before exploring further. # Verify an authorization > Selo fetches `/.well-known/selo-verification.txt` with `GET` (10 second timeout, at most 4096 bytes, redirects followed only within the same origin, at most 3) and looks for a line equal to `expectedContent`. On success the authorization becomes `VERIFIED` for 24 hours. Calling it again on a verified authorization returns it unchanged without fetching. No request body. ## OpenAPI ````yaml /openapi.json post /v1/authorizations/{authorizationId}/verify openapi: 3.1.0 info: title: Selo API version: 1.0.0 summary: CI for x402. It pays your endpoint before your users do. description: >- Selo is a release gate for paid x402 APIs on Algorand. You authorize your endpoint, run a free preflight, then pay Selo 1.00 USDC over x402. Only after that payment settles does Selo pay your endpoint as a real x402 client, run five release checks and return a deterministic PASS, FAIL or INCONCLUSIVE verdict with an Ed25519-signed attestation. There are no API keys. Access to a target is granted per target by authorization; the only paid route is `POST /v1/release-test`, paid with x402. Bodies are JSON, at most 64 KiB. contact: name: Selo url: https://useselo.xyz servers: - url: https://api.useselo.xyz description: Production, Algorand Mainnet security: [] tags: - name: Authorizations description: Prove you control the target before Selo sends it anything. - name: Preflight description: Check for free that a target can be tested and is within budget. - name: Release tests description: The paid x402 route that runs the release checks. - name: Reports description: Private, token-addressed reports of finished release tests. - name: Attestation keys description: Public keys that verify signed verdicts. - name: Discovery description: Machine-readable descriptions of Selo. - name: Health description: Liveness. paths: /v1/authorizations/{authorizationId}/verify: post: tags: - Authorizations summary: Verify an authorization description: >- Selo fetches `/.well-known/selo-verification.txt` with `GET` (10 second timeout, at most 4096 bytes, redirects followed only within the same origin, at most 3) and looks for a line equal to `expectedContent`. On success the authorization becomes `VERIFIED` for 24 hours. Calling it again on a verified authorization returns it unchanged without fetching. No request body. operationId: verifyAuthorization parameters: - name: authorizationId in: path required: true description: >- Authorization ID returned by `POST /v1/authorizations`. A value that is not a well-formed ID returns 404. schema: type: string pattern: ^auth_[0-9A-HJKMNP-TV-Z]{26}$ example: auth_… responses: '200': description: The authorization is verified. content: application/json: schema: $ref: '#/components/schemas/Authorization' examples: verified: summary: Verified value: authorizationId: auth_… status: VERIFIED origin: https://api.example.com routePath: /v1/orders method: POST type: well_known_file verifiedAt: '2026-10-26T12:00:00.000Z' expiresAt: '2026-10-27T12:00:00.000Z' '404': description: No authorization with this ID. content: application/json: schema: $ref: '#/components/schemas/ApiError' examples: NOT_FOUND: summary: Unknown ID value: error: NOT_FOUND message: Authorization auth_… does not exist '409': description: >- The token was not found, or the authorization can no longer be verified. content: application/json: schema: $ref: '#/components/schemas/ApiError' examples: VERIFICATION_FAILED: summary: Token missing value: error: VERIFICATION_FAILED message: >- https://api.example.com/.well-known/selo-verification.txt does not contain the expected selo-verification line CHALLENGE_EXPIRED: summary: Challenge older than one hour value: error: CHALLENGE_EXPIRED message: The verification challenge expired; create a new one AUTHORIZATION_EXPIRED: summary: Verified authorization lapsed value: error: AUTHORIZATION_EXPIRED message: The authorization expired; create a new one AUTHORIZATION_REVOKED: summary: Revoked value: error: AUTHORIZATION_REVOKED message: Authorization auth_… was revoked '422': description: >- Selo refused to fetch the verification file. `error` is the block reason: `TARGET_URL_INVALID`, `TARGET_NOT_HTTPS`, `TARGET_ADDRESS_BLOCKED` (the name resolves to a non-public address), `ORIGIN_NOT_ALLOWED` (a redirect left the origin) or `TOO_MANY_REDIRECTS`. content: application/json: schema: $ref: '#/components/schemas/ApiError' examples: TARGET_ADDRESS_BLOCKED: summary: Resolves to a private address value: error: TARGET_ADDRESS_BLOCKED message: >- Selo refused to fetch https://api.example.com/.well-known/selo-verification.txt ORIGIN_NOT_ALLOWED: summary: Redirect to another origin value: error: ORIGIN_NOT_ALLOWED message: >- Selo refused to fetch https://api.example.com/.well-known/selo-verification.txt '500': $ref: '#/components/responses/InternalError' '502': description: >- The verification file could not be fetched (timeout or network error). content: application/json: schema: $ref: '#/components/schemas/ApiError' examples: VERIFICATION_UNREACHABLE: summary: Unreachable value: error: VERIFICATION_UNREACHABLE message: >- Could not reach https://api.example.com/.well-known/selo-verification.txt components: schemas: Authorization: type: object description: >- Current state of an authorization. Reading it moves a lapsed `PENDING` or `VERIFIED` authorization to `EXPIRED`. required: - authorizationId - status - origin - routePath - method - type - verifiedAt - expiresAt properties: authorizationId: type: string description: '`auth_` plus 26 Crockford base32 characters.' status: $ref: '#/components/schemas/AuthorizationStatus' origin: type: string routePath: type: string method: $ref: '#/components/schemas/HttpMethod' type: $ref: '#/components/schemas/AuthorizationType' verifiedAt: type: - string - 'null' format: date-time description: When Selo verified the token, or `null` while pending. expiresAt: type: string format: date-time description: >- While `PENDING`, when the challenge closes (one hour after creation). Once `VERIFIED`, when the authorization lapses (24 hours after verification). ApiError: type: object description: Error body returned by every failing request. required: - error - message properties: error: type: string description: Stable machine-readable error code, for example `VALIDATION_FAILED`. message: type: string description: Human-readable explanation. Do not parse it. AuthorizationStatus: type: string enum: - PENDING - VERIFIED - EXPIRED - REVOKED description: >- `PENDING`: challenge issued, not yet verified. `VERIFIED`: Selo found the token and may test the target until `expiresAt`. `EXPIRED`: the challenge or the authorization lapsed. `REVOKED`: the authorization was withdrawn. HttpMethod: type: string enum: - GET - POST description: HTTP method Selo uses to call the target. AuthorizationType: type: string enum: - well_known_file - manual_owner_consent description: >- `well_known_file`: verified through `/.well-known/selo-verification.txt` on the target origin. `manual_owner_consent`: an explicit consent recorded by the Selo operator. responses: InternalError: description: Unexpected server error. content: application/json: schema: $ref: '#/components/schemas/ApiError' examples: INTERNAL: summary: Unexpected server error value: error: INTERNAL message: Internal server error ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.