Query official GSA lodging and M&IE per diem rates by city, state, ZIP code, county, and effective date using a normalized REST API built for travel, payroll, ERP, and government contractor workflows.
Data sourced from public U.S. Government per diem and allowance tables. Not affiliated with the U.S. Government or GSA.
The GSA Per Diem API from Allowances API gives developers structured JSON access to CONUS per diem rates used for federal travel reimbursement. Instead of manually downloading tables or reconciling inconsistent public datasets, you can query rates directly by location and date.
Look up active lodging and M&IE rates for CONUS destinations.
Retrieve rates by effective date for audits and past travel claims.
Query by city, state, ZIP code, county, or other supported geography.
Use consistent API responses across GSA, DTMO, and DSSR data sources.
Designed for teams that need repeatable rate lookups, audit trails, and clean API responses inside operational systems.
Support compliant travel reimbursement, invoicing, and DCAA-ready documentation.
Add reliable rate logic to internal tools, approvals, expense reports, and exports.
Query current and historical rates by destination, date, and supported geography.
Fetch GSA CONUS per diem data using a simple REST request.
curl -H "X-API-Key: YOUR_API_KEY" \"https://api.allowancesapi.com/v1/gsa/perdiem/state/NY?city=Albany""source": "GSA","city": "Albany","state": "NY","lodging": 114,"meals_and_incidentals": 68,"effective_date": "2026-01-01"The official GSA Per Diem API is useful when your application only needs CONUS lodging and M&IE rates. Production travel, payroll, ERP, and compliance systems often need more: OCONUS rates, foreign allowances, effective-date lookups, normalized JSON, official-source verification, and support across GSA, DTMO, and DSSR data.
Good for direct lookups of GSA lodging and M&IE rates within the continental U.S.
Adds DSSR, DTMO, OCONUS coverage, historical date logic, normalized responses, verification links, and commercial support.
| Feature | Official GSA Per Diem API | Allowances API |
|---|---|---|
| Foreign and Non-Foreign OCONUS per diem support | ||
|
Foreign allowances beyond per diem
COLA, hardship, LQA, danger pay, education allowances
|
||
| Effective-date lookup by calendar date | ||
| Verification URL back to official source | ||
| Normalized JSON across allowance sources | ||
| Location search for OCONUS destinations | ||
|
Additional GSA lookup helpers
States, counties, destinations, ZIP and ZIP+4 helpers
|
Core endpoints | |
| Standardized API errors with request IDs | ||
| Commercial support for production applications |
Use the official GSA API when you only need raw CONUS per diem data. Use Allowances API when your application needs GSA plus DSSR, DTMO, OCONUS coverage, historical dates, normalized responses, and audit-friendly source verification.
Use Allowances API wherever your application needs accurate per diem rates for reimbursement, compliance, pricing, or reporting.
Calculate reimbursable lodging and M&IE amounts for federal travel or government contractor expense claims.
Preserve historical rate lookups for prior travel dates, invoices, approvals, and audit documentation.
Add per diem lookup logic to ERPNext, NetSuite, Deltek, Microsoft Dynamics, custom finance tools, or internal systems.
Answers to common developer and compliance questions.
Yes. Allowances API provides a developer-friendly GSA per diem API for querying CONUS lodging and M&IE rates in normalized JSON format.
Yes. The API supports location-based GSA rate lookups, including ZIP code, city, state, county, and effective-date workflows depending on the endpoint.
Yes. The API returns GSA lodging rates and meals and incidental expense rates so your application can calculate reimbursable per diem amounts.
Yes. Historical lookups are useful when calculating reimbursements for past travel dates, validating invoices, or supporting DCAA and internal audit reviews.
No. Allowances API is not affiliated with GSA or any U.S. Government agency. Data is sourced from official public per diem and allowance tables.
GSA rates cover CONUS travel. DTMO and DSSR sources are commonly used for Non-Foreign OCONUS and Foreign OCONUS as well as overseas allowance workflows. Allowances API helps normalize these sources behind a consistent API.
Start querying current and historical CONUS lodging and M&IE rates with a normalized API built for production finance, travel, and compliance systems.
Data sourced from official public per diem and allowances tables. Not affiliated with any government agency.