generated: '2026-07-27'
method: searched
source: >-
  Interface Specification for OASIS v3.04
  (https://www.caiso.com/documents/oasisapispecification.pdf), OASIS FAQ
  (https://www.caiso.com/documents/oasis-frequently-asked-questions.pdf), CAISO API Terms
  of Use, and live request/response capture on 2026-07-27
description: >-
  CAISO's two public interfaces are both read-only HTTP GET surfaces with no request body,
  no authentication and no JSON anywhere. The OASIS Download API is a servlet-style query
  interface: one of two servlets (SingleZip, GroupZip) plus a query string naming a report
  and a UTC datetime window, answered with a zip archive containing CIM XML or CSV. The
  Today's Outlook feeds are static-path CSV files regenerated on a five-minute cadence.
  Neither surface uses REST resource paths, content negotiation, cursors, envelopes,
  request ids or conditional requests. Everything below is what CAISO actually publishes
  or what was observed on the wire.
authentication:
  style: none
  detail: Anonymous GET. See authentication/caiso-authentication.yml.
protocol:
  transport: HTTPS (http redirects 302 to https at the BigIP edge)
  methods:
  - GET
  request_body: none
  content_types_returned:
  - application/x-zip-compressed
  - text/csv
  content_negotiation: >-
    None. Format is selected by the resultformat query parameter on OASIS
    (5 = CIM XML, 6 = CSV); Today's Outlook is CSV only.
addressing:
  oasis:
    base: https://oasis.caiso.com/oasisapi
    style: servlet + query string (not REST resource paths)
    operations:
    - servlet: SingleZip
      shape: >-
        /SingleZip?queryname=<REPORT>&startdatetime=<yyyymmddTHH:MM-0000>&enddatetime=<yyyymmddTHH:MM-0000>&version=<n>&resultformat=<5|6>&<report-specific filters>
      note: One report, caller-selected filters.
    - servlet: GroupZip
      shape: /GroupZip?groupid=<GROUP>&startdatetime=<yyyymmddTHH:MM-0000>&version=<n>&resultformat=<5|6>
      note: >-
        A bundle of SingleZips for a whole trade day. opr_hr is required for HASP and RTM
        groups. Use this instead of looping SingleZip when all nodes are needed.
    legacy_form: >-
      The v3.04 specification documents startdate/enddate in yyyymmdd form and the
      /mrtu-oasis context path; the current live context path is /oasisapi and the FAQ's
      current examples use startdatetime/enddatetime with an explicit GMT offset.
  todays_outlook:
    base: https://www.caiso.com/outlook
    style: static file paths
    operations:
    - shape: /current/{report}.csv
      note: Current operating day at five-minute resolution.
    - shape: /history/{YYYYMMDD}/{report}.csv
      note: A past operating day.
    reports:
    - fuelsource
    - demand
    - netdemand
    - co2
parameters:
  common:
  - name: queryname
    where: query
    required: true
    applies_to: SingleZip
    description: Report code. See vocabulary/caiso-oasis-query-names.yml.
  - name: groupid
    where: query
    required: true
    applies_to: GroupZip
    description: Report-group code (for example DAM_LMP_GRP, HASP_LMP_GRP, DA_GROUP).
  - name: startdatetime
    where: query
    required: true
    format: yyyymmddTHH:MM-0000
    description: Inclusive window start, expressed in GMT.
  - name: enddatetime
    where: query
    required: true
    format: yyyymmddTHH:MM-0000
    description: Window end, expressed in GMT.
  - name: version
    where: query
    required: true
    description: >-
      Report schema revision. It is per-report, not global — CAISO's own FAQ examples use
      version=1 (SLD_FCST, SLD_REN_FCST, AS_RESULTS), version=2 (PRC_INTVL_LMP,
      PRC_RTPD_LMP) and version=12 (PRC_LMP).
  - name: resultformat
    where: query
    required: false
    default: 5
    enum:
    - '5'
    - '6'
    description: 5 returns CIM XML, 6 returns CSV. Omitting it yields XML.
  - name: market_run_id
    where: query
    required: conditional
    description: >-
      Market or process the report is drawn from. Values are report-specific; the FAQ
      names 2DA, 7DA, DAM, ACTUAL, RTM for the demand forecast and DAM, ACTUAL, HASP, RTD,
      RTPD for the renewables forecast.
  - name: node
    where: query
    required: conditional
    description: >-
      One or more PNode/APNode names, comma-separated, for the LMP reports.
  - name: grp_type
    where: query
    required: conditional
    description: >-
      Set to ALL (or ALL_APNODES) instead of node to retrieve every node. When retrieving
      ALL, only one hour (interval reports) or one trade date (hourly reports) may be
      requested at a time.
  - name: opr_hr
    where: query
    required: conditional
    applies_to: GroupZip (HASP and RTM groups)
    format: HH
timezone:
  api: GMT
  note: >-
    "REMINDER: The API uses GMT for its Time Zone" (OASIS FAQ, Question Eleven). A
    California trade day therefore starts at T07:00-0000 in winter and T07:00-0000 is the
    offset CAISO's own published examples use. Today's Outlook CSVs are stamped in local
    Pacific clock time in the first column.
response:
  packaging: >-
    Every OASIS response, success or failure, is a zip archive delivered with
    Content-Disposition: inline and a generated filename.
  filename_convention:
    singlezip: startdate_enddate_ReportName_MktRunID_Stamp.zip
    groupzip: startdate_startdate_GroupID_N_xml.zip (or _csv.zip)
    observed: 20260720_20260721_SLD_FCST_DAM_20260727_14_19_18_v1.zip
  xml_schemas:
  - oasisReport.xsd
  - oasisBid.xsd
  - oasiscbBid.xsd
  - oasisMaster.xsd
  xml_note: >-
    Payload XML is CIM-derived and declares the namespace
    http://www.caiso.com/soa/OASISReport_v1.xsd; the XSDs themselves are distributed
    through the access-gated developer site and are not served at that URL.
  disclaimer_block: >-
    Every payload embeds a DISCLAIMER_ITEM stating the contents are subject to change
    without notice.
pagination:
  style: none
  detail: >-
    There is no cursor, offset, page or link header. Volume is controlled by narrowing the
    datetime window and the node/filter set. The 31-day cap (error 1004) and the
    one-hour/one-trade-date cap on all-node pulls are the real windowing constraints.
idempotency:
  mechanism: none
  detail: >-
    No idempotency key exists and none is needed — the entire public surface is read-only
    HTTP GET with no write operations. Repeating a request re-runs the report; for
    "current interval" reports (PRC_CURR_LMP, the Today's Outlook feeds) the same URL
    returns newer data as the operating day advances.
  safe_methods_only: true
caching:
  detail: >-
    GroupZip files are cached server-side — the spec notes cached group files remain
    available roughly one week back from the system date, and a group download already in
    progress returns error 1015 rather than rebuilding.
  http_caching: >-
    No ETag, Last-Modified or Cache-Control conventions are documented, and none were
    observed on the OASIS responses.
tracing:
  request_id: none
  detail: >-
    No request-id or correlation header is returned. The only per-response identifier is
    the timestamp embedded in the generated zip filename and the MessageHeader/TimeDate
    element in the XML payload.
versioning:
  scheme: per-report query parameter (version=<n>)
  api_version: none at the path level (the /oasisapi context path is unversioned)
  detail: >-
    Report schema revisions are selected per request. CAISO's API Terms of Use state that
    "CAISO will occasionally make changes to its API, including backwards incompatible
    changes" and direct callers to register at developer.caiso.com for specifications and
    scheduled modifications. See lifecycle/caiso-lifecycle.yml.
errors:
  in_band: true
  detail: >-
    Application errors return HTTP 200 with an ERROR block (ERR_CODE, ERR_DESC) inside the
    zipped XML. Only the edge throttle uses a real HTTP status (429). Full catalog in
    errors/caiso-error-codes.yml.
rate_limiting:
  detail: >-
    HTTP 429 with an HTML body instructing a five-second retry, enforced at the BigIP
    edge; no rate-limit headers. See rate-limits/caiso-rate-limits.yml.
undocumented_surface:
  note: >-
    CAISO's own API Terms of Use state that "parts of the CAISO API are undocumented,
    including certain methods, events, and properties" and that undocumented behaviour may
    change without notice. Build only against documented query names.
cross_links:
  authentication: authentication/caiso-authentication.yml
  errors: errors/caiso-error-codes.yml
  lifecycle: lifecycle/caiso-lifecycle.yml
  rate_limits: rate-limits/caiso-rate-limits.yml
  vocabulary: vocabulary/caiso-oasis-query-names.yml
  examples: examples/caiso-oasis-examples.yml