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fiat-onramp-cost: Meld adapter verified live (POST + JSON body, BASIC base64(key), Meld-Version header) #2409

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Merged
Flotapponnier merged 1 commit into from
Sep 16, 2026
Merged

fiat-onramp-cost: Meld adapter verified live (POST + JSON body, BASIC base64(key), Meld-Version header) #2409

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18 changes: 11 additions & 7 deletions harnesses/fiat-onramp-cost/CHECKLIST.md
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Original file line number Diff line number Diff line change
Expand Up @@ -66,13 +66,17 @@ Rule from the spec: never invent an endpoint or parameter. Everything below is e

| Item | Status |
|---|---|
| Base hosts `api.meld.io` / `api-sb.meld.io` | VERIFIED in docs |
| Auth `Authorization: BASIC <base64(key:)>` | UNVERIFIED (docs describe BASIC auth with the API key; exact encoding not exercised) |
| Quote path `/payments/crypto/quote` | UNVERIFIED (the reference page returned 404 on 2026-09-10; a search summary names `/payments/virtual-account/quote` for the virtual-account flavour) |
| Params `countryCode`, `sourceCurrencyCode`, `destinationCurrencyCode`, `paymentMethodType`, `sourceAmount` | UNVERIFIED |
| Response `quotes[]{serviceProvider, sourceAmount, destinationAmount, exchangeRate, totalFee, networkFee, transactionFee, partnerFee}` | UNVERIFIED |
| Currency codes `USDC_BASE`, `USDC_ARBITRUM` | UNVERIFIED |
| Live call | UNVERIFIED, no key |
| Base hosts `api.meld.io` / `api-sb.meld.io` | VERIFIED live 2026-09-16 (sandbox key: 200 on `api-sb`, 403 on `api`) |
| Auth `Authorization: BASIC base64(<key>)` | VERIFIED live 2026-09-16. The dashboard key is already `<id>:<secret>`; `base64(key + ":")` gives 403. Adapter fixed. |
| Method / path `POST /payments/crypto/quote` (JSON body) | VERIFIED live 2026-09-16. GET gives 405 METHOD_NOT_ALLOWED. Adapter fixed (was GET with query params). |
| Header `Meld-Version: 2025-03-04` | VERIFIED live (accepted; sent to pin the shape) |
| Body `countryCode`, `sourceCurrencyCode`, `sourceAmount` (number), `destinationCurrencyCode`, `paymentMethodType` | VERIFIED live |
| Response `quotes[]{serviceProvider, sourceAmount, destinationAmount, exchangeRate, totalFee, networkFee, transactionFee, partnerFee (null), paymentMethodType, customerScore, ...}` | VERIFIED live; `partnerFee` is null, parsed as pointer. `testdata` not stored: sandbox numbers are synthetic. |
| Currency codes `BTC`, `ETH`, `USDC_BASE` | VERIFIED live (sandbox lists BANXA only) |
| Errors | VERIFIED: 400 `INVALID_AMOUNT_TOO_HIGH` ("maximum allowed 95.00 EUR for BANXA" on SEPA in sandbox), 408 `QUOTE_TIMEOUT` when a member is slow. 400/404 map to `ErrNoQuote`. |
| Full harness cycle | VERIFIED 2026-09-16 with `MELD_SANDBOX=true`: 6 quotes, labels `via="meld"`, `provider="banxa"`, `cohort="aggregator"`. |
| Sandbox pricing | NOT USABLE for published numbers: BTC quoted at 90,274 EUR vs 65,676 Kraken mid (+3,749 bps), ETH +3,981 bps. Production key required before Meld enters the bench. |
| Production key | PENDING (asked Meld on 2026-09-15; the key received on 2026-09-16 is sandbox-scoped) |

## Excluded from v1 and why

Expand Down
90 changes: 59 additions & 31 deletions harnesses/fiat-onramp-cost/cmd/script/meld.go
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Expand Up @@ -4,19 +4,28 @@ import (
"context"
"encoding/base64"
"encoding/json"
"net/url"
"strings"
"time"
)

// Meld, aggregator. GET {base}/payments/crypto/quote
// Doc: docs.meld.io (fetched 2026-09-10; the reference page for this
// endpoint returned 404 on the path I tried, and the search summary names
// /payments/virtual-account/quote for the virtual-account flavour). Path
// and auth scheme (BASIC with the API key) are UNVERIFIED against live,
// see CHECKLIST.md. countryCode=FR is a documented parameter:
// country_source="param". One quote per member onramp; each becomes a
// sample with via="meld", cohort="aggregator".
// Meld, aggregator. POST {base}/payments/crypto/quote with a JSON body.
// Verified live against api-sb.meld.io on 2026-09-16 (see CHECKLIST.md):
// - Authorization: BASIC base64(<api key>). The key from the dashboard is
// already "<id>:<secret>"; appending ":" before encoding gives 403, and
// GET gives 405 (POST only).
// - Meld-Version: 2025-03-04 pins the response shape.
// - Body: countryCode, sourceCurrencyCode, sourceAmount (number),
// destinationCurrencyCode (network-qualified: BTC, ETH, USDC_BASE),
// paymentMethodType (CREDIT_DEBIT_CARD, SEPA).
// - Response: {quotes:[{serviceProvider, sourceAmount, destinationAmount,
// exchangeRate, totalFee, networkFee, transactionFee, partnerFee|null,
// paymentMethodType, ...}]}; errors are {code, message} with a 4xx
// (INVALID_AMOUNT_TOO_HIGH, QUOTE_TIMEOUT on 408).
// countryCode=FR is a body parameter: country_source="param". One quote per
// member onramp; each becomes a sample with via="meld", cohort="aggregator".
// Sandbox keys work only on api-sb.meld.io and return synthetic rates (BTC
// quoted 37% above spot on 2026-09-16), so MELD_SANDBOX=true is for wiring
// tests, never for published numbers.

type meldAdapter struct {
key string
Expand All @@ -34,28 +43,37 @@ func (m *meldAdapter) base() string {
return baseFor("meld", "https://api.meld.io")
}

// Destination currency codes: Meld qualifies by network in the code
// (UNVERIFIED exact strings).
// Destination currency codes: Meld qualifies by network in the code.
var meldCrypto = map[string]string{
"btc/bitcoin": "BTC", "eth/ethereum": "ETH",
"usdc/base": "USDC_BASE", "usdc/arbitrum": "USDC_ARBITRUM",
}
var meldMethod = map[string]string{"card": "CREDIT_DEBIT_CARD", "sepa": "SEPA"}

type meldQuote struct {
ServiceProvider string `json:"serviceProvider"`
SourceAmount float64 `json:"sourceAmount"`
DestinationAmount float64 `json:"destinationAmount"`
ExchangeRate float64 `json:"exchangeRate"`
TotalFee float64 `json:"totalFee"`
NetworkFee float64 `json:"networkFee"`
TransactionFee float64 `json:"transactionFee"`
PartnerFee float64 `json:"partnerFee"`
PaymentMethodType string `json:"paymentMethodType"`
ServiceProvider string `json:"serviceProvider"`
SourceAmount float64 `json:"sourceAmount"`
DestinationAmount float64 `json:"destinationAmount"`
ExchangeRate float64 `json:"exchangeRate"`
TotalFee float64 `json:"totalFee"`
NetworkFee float64 `json:"networkFee"`
TransactionFee float64 `json:"transactionFee"`
PartnerFee *float64 `json:"partnerFee"` // null when the partner adds no markup
PaymentMethodType string `json:"paymentMethodType"`
}

type meldResp struct {
Quotes []meldQuote `json:"quotes"`
Quotes []meldQuote `json:"quotes"`
Code string `json:"code"` // set on error bodies
Message string `json:"message"` // set on error bodies
}

type meldReq struct {
CountryCode string `json:"countryCode"`
SourceCurrencyCode string `json:"sourceCurrencyCode"`
SourceAmount float64 `json:"sourceAmount"`
DestinationCurrencyCode string `json:"destinationCurrencyCode"`
PaymentMethodType string `json:"paymentMethodType"`
}

var meldProviderSlug = map[string]string{
Expand All @@ -74,18 +92,21 @@ func (m *meldAdapter) Quote(ctx context.Context, req QuoteRequest) ([]Normalized
if !ok {
return nil, 0, ErrNoQuote
}
q := url.Values{}
q.Set("countryCode", PersonaCountry)
q.Set("sourceCurrencyCode", "EUR")
q.Set("destinationCurrencyCode", dest)
q.Set("paymentMethodType", method)
q.Set("sourceAmount", trimFloat(req.Notional))
u := m.base() + "/payments/crypto/quote?" + q.Encode()
auth := "BASIC " + base64.StdEncoding.EncodeToString([]byte(m.key+":"))
res, err := doJSON(ctx, "GET", u, map[string]string{"Authorization": auth}, nil)
body, _ := json.Marshal(meldReq{
CountryCode: PersonaCountry, SourceCurrencyCode: "EUR", SourceAmount: req.Notional,
DestinationCurrencyCode: dest, PaymentMethodType: method,
})
u := m.base() + "/payments/crypto/quote"
auth := "BASIC " + base64.StdEncoding.EncodeToString([]byte(m.key))
res, err := doJSON(ctx, "POST", u, map[string]string{"Authorization": auth, "Meld-Version": "2025-03-04"}, body)
if err != nil {
return nil, res.Latency, err
}
if res.Status == 400 || res.Status == 404 {
// INVALID_AMOUNT_TOO_HIGH, no provider for the cell, unsupported
// currency: a cell the aggregator cannot serve, not an outage.
return nil, res.Latency, ErrNoQuote
}
if res.Status != 200 {
return nil, res.Latency, statusErr("meld", res)
}
Expand Down Expand Up @@ -117,7 +138,7 @@ func (m *meldAdapter) Quote(ctx context.Context, req QuoteRequest) ([]Normalized
Asset: req.Asset.Asset, Network: req.Network, PaymentMethod: req.PaymentMethod,
Notional: req.Notional, CountrySource: "param",
FiatIn: fiatIn, CryptoOut: mq.DestinationAmount,
FeeProvider: mq.TransactionFee, FeeNetwork: mq.NetworkFee, FeePartner: mq.PartnerFee,
FeeProvider: mq.TransactionFee, FeeNetwork: mq.NetworkFee, FeePartner: derefFloat(mq.PartnerFee),
ProviderMarketRate: mq.ExchangeRate, RawJSONHash: h,
})
}
Expand All @@ -128,3 +149,10 @@ func (m *meldAdapter) Quote(ctx context.Context, req QuoteRequest) ([]Normalized
}

func (m *meldAdapter) CountrySource() string { return "param" }

func derefFloat(p *float64) float64 {
if p == nil {
return 0
}
return *p
}
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