Timezone Offset At Instant

time.timezone_offset_at

ProductionBounded custom (Class B)Deterministicstrictinstantv1.0.0

No network

Overview

You send an RFC 3339 instant with an offset or Z, and an IANA zone. We return the offset in force at that instant, the offset in seconds, whether daylight saving applied, and a display abbreviation. Legacy three-letter zone names such as CST are refused. This is not a local-time disambiguator and not a lookup from a city name. The answer depends on the bundled IANA tzdb version, reported in _meta.

Offset arithmetic that ignores DST and historical LMT minutes is how stored instants get displayed an hour off. Reading the zone rules at the instant is the contract.

Reliability

Same instant, same zone, same tzdb version, same answer. Abbreviation is display metadata and must not be sent back as zoneId. TIMEZONE_UNKNOWN — trigger: zoneId is not a resolvable IANA region id, including CST-style abbreviations and raw offsets; retryable: no; next: send America/New_York or UTC. DATETIME_FORMAT_INVALID — trigger: instant is not RFC 3339 with an offset or Z; retryable: no; next: send 2026-01-15T17:00:00Z rather than a zone-less local time.

Context footprint

One instant and one zone in. A successful call costs 1 execution credit.

When to use it

When you already have an instant and need the offset that one IANA zone used then.

When you have a zone-less local wall time, or you need to convert between two zones.

Scope

Note

Returns the UTC offset of one IANA zone at one RFC 3339 instant.

Non-goals

Does not disambiguate a zone-less local time (use time.resolve_local_datetime)
Does not infer a zone from a city, country, or phone prefix

Properties

IdempotentRetry safeStreaming supportedFile input supportedRequires external service

Capabilities

analysis

Cost & billing

Flat rate per invocation

MetercallsBillable onsuccessCost per call1 credit

File handling

Accepts file_refProduces file_refMax input2 KB

How we handle your data

Sensitive input, safe output

What this means

This skill may receive sensitive content, but it does not target sensitive data and returns only a structured non-sensitive result.

Squillify guarantees

Runs inside Squillify
This skill runs inside Squillify.
Payloads are not sent to an external service by this skill.
Squillify does not permanently store submitted payloads.
Telemetry records metadata only, not submitted content.
Submitted payloads are not used for training.
Submitted payloads are not reviewed by humans.
This skill does not target sensitive data.
The response does not contain submitted content.

Your responsibility

Squillify does not determine whether submitted content is sensitive. Your application is responsible for deciding what data it is allowed to submit. Your application is responsible for securing the response.

Read the Microskill Data Handling Policy

Input schema

Field	Type	Required	Description
instant	string	Yes	RFC 3339 date-time with offset or Z.
zoneId	string	Yes	IANA region zone or UTC.

Output schema

Field	Type	Required	Description
instant	string	Yes	Instant normalized to UTC.
zoneId	string	Yes	Canonical IANA zone.
offset	string	Yes	UTC offset as ±HH:MM[:SS].
offsetSeconds	integer	Yes	The same UTC offset expressed as a signed count of seconds, including LMT seconds.
daylightSaving	boolean	Yes	Whether daylight saving applied.
abbreviation	string	Yes	Display abbreviation.
_meta	object	Yes	Closed applied tzdb receipt naming the IANA tzdbVersion used.

API contract

POST /v1/execute

curl

curl -sS -X POST "$BASE/v1/execute" -H "Authorization: Bearer $KEY" -H 'Content-Type: application/json' -d '{"skillKey":"time.timezone_offset_at","input":{"instant":"2026-01-15T17:00:00Z","zoneId":"America/New_York"}}'

Integrations

TypeScript SDK

import { Squillify } from "@squillify/sdk";

const sq = new Squillify({ apiKey: process.env.SQUILLIFY_API_KEY });

const { output } = await sq.execute("time.timezone_offset_at", {"zoneId":"America/New_York","instant":"2026-01-15T17:00:00Z"});

Errors

Code	HTTP	Retryable	Description
VALIDATION_ERROR	400	No	The request payload failed schema validation.
UNAUTHORIZED	401	No	Missing or invalid API key.
SKILL_NOT_ACCESSIBLE	403	No	The API key is not granted access to this skill.
SKILL_NOT_AVAILABLE_FOR_PLAN	403	No	This skill is not included in your current plan.
PLAN_ELIGIBILITY_UNAVAILABLE	503	Yes	Plan eligibility could not be decided. Retry after backoff.
SKILL_NOT_FOUND	404	No	The requested skill or version does not exist.
TENANT_RATE_LIMITED	429	Yes	Request rate limit exceeded. Retry after backoff.
QUOTA_EXCEEDED	429	Yes	Plan quota exhausted. Retryable once the quota period resets.
EXECUTION_TIMEOUT	504	Yes	Execution exceeded the allowed time budget.
TIMEZONE_UNKNOWN	400	No	The request payload failed this skill's input validation.
DATETIME_FORMAT_INVALID	400	No	The request payload failed this skill's input validation.

Other limits

Limit	Value
Recommended inline bytes	32 KiB

Limitations

Does not disambiguate a zone-less local time (use time.resolve_local_datetime)
Does not infer a zone from a city, country, or phone prefix
Converting a local wall time between two zones (use time.convert_timezone)
Resolving 02:30 on a fall-back night (use time.resolve_local_datetime)

How to call

POST /v1/execute (requires authentication)

Request bodyjson

{
  "skillKey": "time.timezone_offset_at",
  "input": {
    "zoneId": "America/New_York",
    "instant": "2026-01-15T17:00:00Z"
  }
}

Examples

New York standard time in January

Inputjson

{
  "zoneId": "America/New_York",
  "instant": "2026-01-15T17:00:00Z"
}

Expected outputjson

{
  "_meta": {
    "tzdbVersion": "2026b"
  },
  "abbreviation": "EST",
  "instant": "2026-01-15T17:00:00Z",
  "offsetSeconds": -18000,
  "offset": "-05:00",
  "daylightSaving": false,
  "zoneId": "America/New_York"
}

Tip

America/New_York is EST −05:00 in mid-January

New York daylight time in July