feat(rails): add ACH_SAME_DAY payment rail by jacklatourette · Pull Request #931 · lightsparkdev/grid-api

jacklatourette · 2026-09-10T00:21:34Z

What

Adds ACH_SAME_DAY to the PaymentRail enum alongside the existing ACH, and to the
paymentRails array on UsdAccountInfo.

Why

Grid exposes one ACH rail today. Every ACH payout it originates already settles same
day, because the sponsor bank's default service level is same-day and nothing in the
request path ever asks for a different one. A platform therefore cannot choose
standard ACH, and the two speeds cannot be priced apart.

Splitting the rail gives platforms an explicit choice, and gives each speed its own
RailFeeConfig.

The `paymentRails` array is the part that matters at runtime

The top-level enum alone is not enough. The generated client validates an account's
paymentRails against the array on UsdAccountInfo, so advertising the rail on a USD
account without that entry makes GET /customers/external-accounts/{id} return 500
— verified against a live account.

UsdAccountInfo is composed by PaymentUsdAccountInfo and UsdExternalAccountInfo, so
the single entry covers all three generated models.

What this means for integrators

ACH_SAME_DAY requests same-business-day settlement and is priced separately. It is
capped at $1,000,000 per entry by the NACHA same-day limit, rising to $10,000,000
on 2027-09-17. A payout above the cap is rejected, not slowed — send it over ACH
instead. Refusing lets the customer choose the slower rail rather than being quietly
given something they did not ask for, and stating the figure lets them check the
amount before they are refused.
The prose docs said the opposite. send-payment.mdx, snippets/sending/accounts.mdx
and the changelog all still described the downgrade — the changelog explicitly said an
over-cap payout "is not rejected". All three now match the spec.
ACH will settle on the standard next-business-day schedule. Until an announced
date it continues to settle same-business-day on production platforms, and already
settles next-business-day on sandbox platforms. The descriptions say so explicitly
rather than claiming next-day everywhere, because that would be wrong for every
production customer until the cutover.
RailFeeConfig accepts ACH_SAME_DAY. The two are separate rails, so price each one
with its own config.

The change is additive to both enums. No existing field changes shape.

Docs

The pages that enumerate rails now list it: the US row of the country support table, the
paymentRail tip on both sending pages, and the rail-fee limits on the fees page. The
changelog gets a September 2026 entry.

Sequencing

Backend support lands separately in webdev under AT-6555, which regenerates its vendored
client from this branch. Until that ships, a request naming ACH_SAME_DAY is declined by
the backend, so hold this if you would rather the docs never advertise a rail the API
does not yet accept.

Verification

Rebased onto current main (was 45 behind). One conflict, in the changelog, where both
sides added September entries; both kept.
make build rebundles cleanly; openapi.yaml and mintlify/openapi.yaml are in sync.
make lint-openapi exits 0: 866 problems, 0 errors (174 warnings, 692 infos, all
pre-existing and unrelated — the 2 redocly warnings are paths-kebab-case).
make lint-markdown cannot run locally: package.json has no lint:markdown script.
CI's "Lint Code & Documentation" job covers it.

🤖 Generated with Claude Code

https://claude.ai/code/session_01RUF3krYG9C9hShf4iS5Sug

vercel · 2026-09-10T00:21:36Z

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mintlify · 2026-09-10T00:21:37Z

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Project	Status	Preview	Updated
Grid	🟢 Ready	View Preview	Sep 22, 2026, 11:52 PM

jacklatourette · 2026-09-10T00:21:51Z

feat(rails): add ACH_SAME_DAY payment rail #931 👈 (View in Graphite)
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github-actions · 2026-09-10T00:22:17Z

✱ Stainless preview builds for grid

This PR will update the grid SDKs with the following commit messages.

cli

chore(internal): regenerate SDK with no functional changes

go

feat(api): add ACH_SAME_DAY payment rail across transactions/transfers/config

kotlin

feat(api): add ACH_SAME_DAY payment rail enum value across config and transaction models

openapi

feat(api): add ACH_SAME_DAY payment rail option

php

feat(api): add ACH_SAME_DAY to payment rail enums

python

feat(api): add ACH_SAME_DAY rail type to transfers and config

ruby

feat(api): add ACH_SAME_DAY payment rail option

typescript

feat(api): add ACH_SAME_DAY rail to config/accounts/transactions/transfers

Edit this comment to update them. They will appear in their respective SDK's changelogs.

✅ grid-typescript studio · code · diff

Your SDK build had at least one "error" diagnostic, but this did not represent a regression.
generate ❗ → build ⏭️ → lint ⏭️ → test ⏭️

✅ grid-cli studio · code · diff

Your SDK build had at least one "error" diagnostic, but this did not represent a regression.
generate ❗ → build ⏭️ → lint ⏭️ → test ⏭️

✅ grid-openapi studio · code · diff

Your SDK build had at least one "error" diagnostic, but this did not represent a regression.
generate ❗

✅ grid-kotlin studio · code · diff

Your SDK build had at least one "error" diagnostic, but this did not represent a regression.
generate ❗ → build ⏭️ (prev: build ✅) → lint ⏭️ (prev: lint ✅) → test ⏭️ (prev: test ❗)

✅ grid-ruby studio · code · diff

Your SDK build had at least one "error" diagnostic, but this did not represent a regression.
generate ❗ → build ⏭️ → lint ⏭️ → test ⏭️

✅ grid-go studio · code · diff

Your SDK build had at least one "error" diagnostic, but this did not represent a regression.
generate ❗ → build ⏭️ → lint ⏭️ → test ⏭️
go get github.com/stainless-sdks/grid-go@76ee63e9b3faf0809cd2965fc6692a414ffb8bf5

✅ grid-python studio · code · diff

Your SDK build had at least one "error" diagnostic, but this did not represent a regression.
generate ❗ → build ⏭️ → lint ⏭️ → test ⏭️

✅ grid-php studio · code · diff

Your SDK build had at least one "error" diagnostic, but this did not represent a regression.
generate ❗ → lint ⏭️ → test ⏭️

This comment is auto-generated by GitHub Actions and is automatically kept up to date as you push.
If you push custom code to the preview branch, re-run this workflow to update the comment.
Last updated: 2026-09-22 23:55:33 UTC

greptile-apps · 2026-09-10T00:23:35Z

Confidence Score: 5/5

The PR appears safe to merge, with the source and generated contract views aligned and no actionable contract defect identified.

Summary

Keeps the modular schema and both generated OpenAPI bundles aligned.
Allows separate fee configurations for standard and same-day ACH.
Documents the distinction between next-business-day ACH and requested same-business-day settlement.

_{Reviews (1) · Last reviewed commit: "feat(rails): add ACH_SAME_DAY payment ra..."}

Grid exposes one ACH rail today, so a platform cannot choose between standard and same-day settlement and the two cannot be priced apart. Add ACH_SAME_DAY alongside ACH in PaymentRail, and to the paymentRails array on UsdAccountInfo. The array is the one that matters at runtime: the generated client validates paymentRails against it, so advertising the rail on a USD account without this entry makes GET /customers/external-accounts/{id} return 500. UsdAccountInfo is composed by PaymentUsdAccountInfo and UsdExternalAccountInfo, so the single entry covers all three generated models. Describe the rails as they will actually behave on release. ACH keeps settling same-business-day on production platforms until an announced date, and already settles next-business-day on sandbox, so the description says so rather than claiming next-day everywhere. An over-cap same-day request settles on the standard schedule and is priced accordingly; it is not rejected. RailFeeConfig accepts the new rail, and its description now says the two are separate rails that each need their own fee config. The docs pages that enumerate rails list the new one: the US row of the country support table, the paymentRail tip on the sending pages, the rail-fee limits on the fees page, and a changelog entry. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01RUF3krYG9C9hShf4iS5Sug

The description said an over-limit payout 'settles on the standard schedule and is priced accordingly'. Grid now refuses it instead, so a customer who named the fast rail chooses the slower one themselves rather than being moved to it silently. Plain ACH is never refused by this limit. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01RUF3krYG9C9hShf4iS5Sug

… is refused The prose still described the downgrade the spec had already dropped, and the changelog said an over-cap payout "is not rejected" — the inverse of what the API does. None of it named the limit, so an integrator could only discover it by being refused. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

mintlify Bot deployed to staging - mintlify September 10, 2026 00:22 View deployment

jacklatourette force-pushed the AT-6555-add-ach-same-day-payment-rail branch from 38e2c6c to 71fa3d2 Compare September 10, 2026 17:57

github-actions Bot added the breaking-change Introduces a breaking change to the OpenAPI spec label Sep 10, 2026

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jacklatourette force-pushed the AT-6555-add-ach-same-day-payment-rail branch from 71fa3d2 to 8e4ddb9 Compare September 15, 2026 23:12

github-actions Bot removed the breaking-change Introduces a breaking change to the OpenAPI spec label Sep 15, 2026

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jacklatourette force-pushed the AT-6555-add-ach-same-day-payment-rail branch from 8e4ddb9 to 4741fd0 Compare September 17, 2026 20:34

mintlify Bot deployed to staging - mintlify September 17, 2026 20:36 View deployment

jacklatourette force-pushed the AT-6555-add-ach-same-day-payment-rail branch from 4741fd0 to 90faaf4 Compare September 17, 2026 22:17

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jacklatourette force-pushed the AT-6555-add-ach-same-day-payment-rail branch from 5a3b0cf to d4f0f2f Compare September 18, 2026 21:14

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jacklatourette force-pushed the AT-6555-add-ach-same-day-payment-rail branch from d4f0f2f to 6ce9f23 Compare September 21, 2026 23:29

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jacklatourette and others added 3 commits September 22, 2026 16:51

jacklatourette force-pushed the AT-6555-add-ach-same-day-payment-rail branch from 4e7e563 to b55ce40 Compare September 22, 2026 23:52

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jacklatourette requested a review from gcamata September 22, 2026 23:56

bsiaotickchong approved these changes Sep 23, 2026

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feat(rails): add ACH_SAME_DAY payment rail - #931

feat(rails): add ACH_SAME_DAY payment rail#931
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jacklatourette commented Sep 10, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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What

Why

The paymentRails array is the part that matters at runtime

What this means for integrators

Docs

Sequencing

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jacklatourette commented Sep 10, 2026 •

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The `paymentRails` array is the part that matters at runtime

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